WO2004010469A2 - Atomic layer deposition of multi-metallic precursors - Google Patents

Atomic layer deposition of multi-metallic precursors Download PDF

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Publication number
WO2004010469A2
WO2004010469A2 PCT/US2003/022236 US0322236W WO2004010469A2 WO 2004010469 A2 WO2004010469 A2 WO 2004010469A2 US 0322236 W US0322236 W US 0322236W WO 2004010469 A2 WO2004010469 A2 WO 2004010469A2
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Prior art keywords
metallic
film
gas
reactant
precursors
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PCT/US2003/022236
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French (fr)
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WO2004010469A3 (en
Inventor
Yoshihide Senzaki
Sang-In Lee
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Aviza Technology, Inc.
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Priority to AU2003267995A priority Critical patent/AU2003267995A1/en
Priority to EP03748943A priority patent/EP1523763A4/en
Priority to JP2004523467A priority patent/JP2005533390A/en
Publication of WO2004010469A2 publication Critical patent/WO2004010469A2/en
Publication of WO2004010469A3 publication Critical patent/WO2004010469A3/en

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    • H—ELECTRICITY
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    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02225—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
    • H01L21/0226—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process
    • H01L21/02263—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase
    • H01L21/02271—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition
    • H01L21/0228—Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process deposition from the gas or vapour phase deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/308—Oxynitrides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/34—Nitrides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/40—Oxides
    • C23C16/401—Oxides containing silicon
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
    • C23C16/455—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
    • C23C16/45523—Pulsed gas flow or change of composition over time
    • C23C16/45525—Atomic layer deposition [ALD]
    • C23C16/45527—Atomic layer deposition [ALD] characterized by the ALD cycle, e.g. different flows or temperatures during half-reactions, unusual pulsing sequence, use of precursor mixtures or auxiliary reactants or activations
    • C23C16/45531—Atomic layer deposition [ALD] characterized by the ALD cycle, e.g. different flows or temperatures during half-reactions, unusual pulsing sequence, use of precursor mixtures or auxiliary reactants or activations specially adapted for making ternary or higher compositions
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
    • C23C16/455—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
    • C23C16/45523—Pulsed gas flow or change of composition over time
    • C23C16/45525—Atomic layer deposition [ALD]
    • C23C16/45553—Atomic layer deposition [ALD] characterized by the use of precursors specially adapted for ALD
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
    • H01L21/02205—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates the layer being characterised by the precursor material for deposition
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
    • H01L21/02205—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates the layer being characterised by the precursor material for deposition
    • H01L21/02208—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates the layer being characterised by the precursor material for deposition the precursor containing a compound comprising Si
    • H01L21/02219—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates the layer being characterised by the precursor material for deposition the precursor containing a compound comprising Si the compound comprising silicon and nitrogen
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268
    • H01L21/283—Deposition of conductive or insulating materials for electrodes conducting electric current
    • H01L21/285—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation
    • H01L21/28506—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers
    • H01L21/28512—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers on semiconductor bodies comprising elements of Group IV of the Periodic System
    • H01L21/28556—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers on semiconductor bodies comprising elements of Group IV of the Periodic System by chemical means, e.g. CVD, LPCVD, PECVD, laser CVD
    • H01L21/28562—Selective deposition
    • H—ELECTRICITY
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    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
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    • H01L21/02123—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon
    • H01L21/02142—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon the material containing silicon and at least one metal element, e.g. metal silicate based insulators or metal silicon oxynitrides
    • H01L21/02148—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon the material containing silicon and at least one metal element, e.g. metal silicate based insulators or metal silicon oxynitrides the material containing hafnium, e.g. HfSiOx or HfSiON
    • H—ELECTRICITY
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    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H01L21/02107—Forming insulating materials on a substrate
    • H01L21/02109—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
    • H01L21/02112—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer
    • H01L21/02123—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon
    • H01L21/02142—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon the material containing silicon and at least one metal element, e.g. metal silicate based insulators or metal silicon oxynitrides
    • H01L21/02153—Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates characterised by the material of the layer the material containing silicon the material containing silicon and at least one metal element, e.g. metal silicate based insulators or metal silicon oxynitrides the material containing titanium, e.g. TiSiOx

Definitions

  • the present invention relates to the field of semiconductors. More specifically, the present invention relates to the atomic layer deposition (ALD) of thin conformal homogeneous multi-metallic films onto semiconductor devices and wafers.
  • ALD atomic layer deposition
  • MOS metal-oxide-silicon
  • Thin multi-metallic films are of increasing interest in the microelectronic industry. For example, hafnium silicate (Hf-Si-O) films are considered a possible alternative gate oxide film to silicon oxide (Si-O) films. Similarly, tantalum silicon nitride (Ta-Si-N) films are reported to have better properties than tantalum nitride (TaN) films as a barrier for copper interconnect.
  • hafnium silicate Hf-Si-O
  • Si-O silicon oxide
  • Ta-Si-N tantalum silicon nitride
  • CVD chemical vapor deposition
  • two or more reactant gases are mixed together in a deposition chamber where the gases either react in the gas phase and precipitate a film onto a substrate's surface or react directly on the substrate's surface.
  • Deposition by CVD occurs for a specified length of time, based on the desired thickness of the deposited film. Since the specified time is a function of the flux of reactants into the chamber, the required time may vary from chamber to chamber. CVD is increasingly unable to meet the requirements for making advanced thin films.
  • CVD requires high processing temperatures and makes inefficient use of reactants. In addition, CVD results in the presence of a relatively high level of impurities in the resultant film. Finally, CVD is limited in its ability to deposit ultra-thin homogeneous conformal films for high k gate dielectrics onto wafers.
  • Atomic layer deposition is an alternative to traditional CVD for depositing thin films, i a conventional ALD deposition cycle, each reactant gas is introduced sequentially into the chamber, so that no gas phase intermixing occurs. A monolayer of a first reactant (i.e., precursor) is physi- or chemisorbed onto the substrate's surface.
  • Excessive first reactant is then evacuated, usually with the aid of an inert purge gas and/or pumping.
  • a second reactant is then introduced to the deposition chamber and reacts with the first reactant to form a mono-layer of the desired film through a self-limiting surface reaction.
  • the self-limiting reaction stops once the initially adsorbed first reactant fully reacts with the second reactant.
  • Excessive second reactant is evacuated usually with the aid of an inert purge gas and/or pumping.
  • a desired film thickness is obtained by repeating the deposition cycle as necessary.
  • the film thickness can be controlled to atomic layer (i.e., angstrom scale) accuracy by counting the number of deposition cycles.
  • ALD has several advantages over traditional CVD.
  • one problem with conventional ALD processes is the low throughput that results from long cycle times.
  • Conventional ALD processes perform a relatively slow "layer- by layer” growth using alternating doses of precursor and reactant. This problem is exacerbated when the deposited film is a multi-metallic film, since multiple precursors are employed.
  • the deposition rate of multi-metallic films is typically less than 1 A per cycle. To be useful in semiconductor manufacturing, an ALD process must demonstrate an acceptable throughput.
  • ALD processes Another difficulty in the production of multi-metallic films using conventional ALD processes is the non-homogeneity of the resultant film. Homogenous films are desired, for example, in MOS device applications.
  • Conventional ALD processes due to the use of alternating doses of chemical sources, form films that are a series of phase separated nano- laminates. Subsequent high temperature annealing is required to inter-diffuse the multiple elements to form a homogeneous composition. Accordingly, there is a significant need in the industry for further developments.
  • the present invention provides new ALD methods for depositing conformal homogeneous multi-metallic films onto substrates.
  • Films that may be deposited by the ALD method of the present invention include metallic alloy films, multi-metallic oxide films, multi-metallic nitride films, and multi-metallic oxynitride films.
  • ALD depositions embraced by the method of the present invention include thermal ALD, photo-assisted ALD, laser assisted ALD, plasma-assisted ALD and radical assisted ALD.
  • a first ALD method for forming a multi-metallic film on a substrate comprises at least one cycle that comprises the step of introducing a multi-metallic molecular precursor gas into a deposition chamber that contains the substrate.
  • the multi-metallic molecular precursor comprises all of the metallic elements necessary to make a homogeneous mono-layer of the film.
  • One example of a multi- metallic molecular precursor is tri-(tert-butoxy)siloxy-tri(tert-butoxy)titanium - (tBuO) 3 Si-O- Ti(OtBu) 3 - which can be used to deposit titanium silicate (Ti-Si-O) films when the subsequent reactant is an oxygen source.
  • the first ALD method includes at least one cycle that comprises the following steps: (i) introducing a multi-metallic molecular precursor gas into a deposition chamber that contains a substrate; (ii) purging the deposition chamber; (iii) introducing one or more reactant gases to the deposition chamber; and (iv) purging the deposition chamber.
  • the multi-metallic molecular precursor is physi-or chemisorbed onto the substrate's surface and the subsequent reactant cleaves any undesirable ligands from the precursor, leaving a mono-layer of the desired multi-metallic film.
  • the reactant can be any oxidizing or reducing agent or mixture thereof and is selected to convert the physi-or chemisorbed precursor into the type of multi-metallic film desired. Each time the cycle is repeated, another mono-layer is added. In this manner, a conformal homogeneous film of the desired thickness and composition can be nano-engineered.
  • a second ALD method for forming a multi-metallic film on a substrate comprising at least one cycle that comprises the step of introducing a mixture of metallic molecular precursor gases into a deposition chamber that contains the substrate.
  • the mixture of precursors comprises all of the metallic elements necessary to make a homogeneous mono-layer of the film.
  • a suitable precursor cocktail is a mixture of the two compounds Hf(NEtMe) 2 and Si(NEtMe) 2 - which can be used to deposit hafnium silicate (Hf-Si-O) films when the subsequent reactant is an oxygen source.
  • the first ALD method comprises at least one cycle that comprises the following steps: (i) introducing a mixture of at least two different metallic molecular precursors to a deposition chamber; (ii) purging the deposition chamber; (iii) introducing a reactant gas to the deposition chamber; and (iv) purging the deposition chamber.
  • the mixture, or cocktail, of metallic molecular precursors is first physi- or chemisorbed onto the substrate's surface and the subsequent reactant cleaves any undesirable ligands from the precursors, leaving a mono-layer of the desired multi-metallic film.
  • the reactant can be any oxidizing or reducing agent or combination thereof and is selected to convert the physi- or chemisorbed precursors into the type of multi-metallic film desired.
  • the cycle is repeated, another mono-layer is added.
  • a conformal homogeneous film of the desired thickness and composition can be nano- engineered.
  • Both methods permit all of the metallic elements necessary to make the multi-metallic film to be supplied in a single dose, or pulse, in each deposition cycle.
  • the inventions provide several benefits. First, the inventions significantly reduce ALD process cycle time and, thereby, increase throughput. Second, the inventions form homogeneous films as- deposited, which eliminates the need for subsequent annealing. Third, the inventions increase efficiency by reducing the number of particles generated in the gas phase during the film deposition process.
  • FIGS. 1A, IB and 1C illustrate schematic diagrams of an ALD systems and method according to various embodiments of the present invention
  • FIGS. 2A, 2B, 2C and 2D also illustrates ALD systems and methods according to additional embodiments of the present invention
  • FIG. 3 illustrates a schematic diagram of an ALD system and method of the present invention.
  • FIG. 4 is a TEM cross section image of a 45 A Hfo. 58 Sio. 2 O film made in accordance with one of the ALD methods of the present invention.
  • Metal is an element selected the following elements in the periodic table: Li; Be; Na; Mg; Al; K; Ca; Sc; Ti; V; Cr; Mn; Fe; Co; Ni; Cu; Zn; Ga; Ge; Rb; Sr; Y ; Zr; Nb; Mo; Tc; Ru; Rh; Pd; Ag; Cd; In; Sn; Sb; Cs; Ba; La; Hf; Ta; W; Re; Os; Ir; Pt; Au Hg; Tl; Pb; Bi; Po; Fr; Ra; Ac; Ce; Pr; Nd; Pm; Sm; Eu; Gd; Tb; Dy; Ho; Er; Tm; Yb; Lu
  • Metalloid as used herein is an element selected from the following elements in the periodic table: B; Si; Ge; As; Sb; Te and At.
  • Metallic indicates the presence of at least one element selected from metals and metalloids as defined above.
  • Multi-metallic indicates the presence of two or more elements selected from metals and metalloids as defined above.
  • Molecular precursor as used herein is a reactant used to introduce atoms or chemical groups onto a substrate to form a film.
  • the molecular precursor is physi- or chemisorbed onto the surface of a substrate and must be modified by a subsequent reactant or reactants to produce the desired film.
  • Metallic molecular precursor as used herein is a molecular precursor that contains at least one element selected from metals and metalloids as defined above.
  • Multi-metallic molecular precursor as used herein is a molecular precursor that contains at least two elements selected from metals and metalloids as defined above.
  • Leaving groups and “ligands,” as used interchangeably herein, refer to atoms or chemical groups in a metallic molecular precursor that are attached, covalently or non- covalently, to the metallic components therein.
  • Haldrogen source means any compound that contains within its structure reactive hydrogen and includes but is not limited to hydrogen gas and the like.
  • Oxygen source means any compound that contains within is structure a reactive oxygen including but not limited to atomic oxygen, oxygen gas, ozone, water, alcohols, hydrogen peroxide and the like.
  • Neitrogen source means any compound that contains within its structure a reactive nitrogen and includes but is not limited to atomic nitrogen, nitrogen gas, ammonia, hydrazine, alkylhydrazine, alkylamine and the like.
  • Multi-metallic film as used herein is any film whose components, not counting any contaminants, includes two or more elements selected from metals and metalloids as defined above.
  • Illustrative multi-metallic films include but are not limited to metallic alloy films, multi-metallic oxide films, multi-metallic nitride films and multi-metallic oxynitride films.
  • Metallic alloy film as used herein is a film formed principally from metal and/or metalloid elements as defined above.
  • Oxide film as used herein is a film formed principally from oxygen and at least one type of metal or metalloid as defined above.
  • Niride film as used herein is a film formed principally from nitrogen and at least one type of metal or metalloid as defined above.
  • Oxynitride film as used herein is a film formed principally from oxygen, nitrogen, and at least one type of metal or metalloid as defined above.
  • a multi-metallic molecular precursor is utilized in an ALD process to deposit conformal homogeneous multi-metallic films onto substrates.
  • a mixture, or cocktail, of two or more metallic molecular precursors is utilized in an ALD process to deposit conformal homogeneous multi-metallic films onto substrates.
  • all of the metallic elements necessary to make the multi-metallic films are introduced in a single dose or pulse in each deposition cycle.
  • the present invention eliminates the need to alternate pulses of two or more metallic precursors and, thereby, increases throughput. Furthermore, the present invention generates a homogeneous film as deposited, thereby eliminating the need to subsequently anneal the film. The invention reduces the particles generated in the gas phase during the film deposition, among other advantages.
  • a first ALD method for forming multi-metallic films on a substrate comprises at least one cycle that comprises the step of introducing a multi-metallic molecular precursor gas into a deposition chamber that contains a substrate.
  • the method for forming multi-metallic films on a substrate comprises at least one cycle that comprises the following steps: (i) introducing a multi-metallic molecular precursor gas into a deposition chamber that contains a substrate; (ii) purging the deposition chamber; (iii) introducing one or more reactant gases to the deposition chamber; and (iv) purging the deposition chamber.
  • the multi-metallic molecular precursor contains, within each molecule, the different metallic elements required to make the desired film.
  • the multi-metallic molecular precursor comprises the following formula: (L' ⁇ GM ⁇ b where M 1 and M 2 are different metallic elements, where each L 1 and L 2 is a leaving group (ligand) and may be the same or different, where a and b are integers less than a valence number for M 1 and M 2 , respectively, and where G is selected from a single bond, double bond, bridging atom and bridging group.
  • M 1 and M 2 can be any metallic element as long as M 1 and M 2 are not identical.
  • Preferred metallic elements for use as M 1 and M 2 include Si, Li, Be, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th.
  • G can be a single bond, double bond, bridging atom or bridging group.
  • R s is selected from hydrogen and C1-C6 alkyls.
  • L 1 and L 2 is selected, independently, from ligands and may be the same or different.
  • Suitable ligands are readily ascertainable by those of ordinary skill in the art and include those ligands known to be useful in precursors for ALD processes. Undesirable ligands are removed during the course of film deposition due to their relatively weak chemical bonds.
  • Preferred ligands include alkyls, alkoxides, halides, hydrides, amides, imides, azides, nitrates, cyclopentadienyls, carbonyls, carboxylates, diketonates, as well as substituted analogs thereof and combinations thereof. It is preferable, but not necessary to use relatively small ligands having, e.g., 1-12 atoms.
  • ligands that contain small relatively small ligands tend to volatilize more readily at lower temperatures than compounds that contain relatively larger ligands.
  • Specific preferred ligands include dimethylamide (-N(CH 3 ) 2 ), diethylamide (- N(CH 2 CH 3 ) 2 ), methylethylamide (-N(CH 3 )(CH 2 CH 3 )) 5 methoxide (-OCH 3 ), ethoxide (- OCH 2 CH 3 ), and butoxide (-O(CH 2 ) 3 CH 3 ).
  • a and b are integers less than a valence number for M 1 and M 2 , respectively.
  • a an b are integers one less than a valence number for M 1 and M 2 , respectively. More preferably, a and b are selected, independently, from 1, 2 and 3.
  • the multi -metallic precursor comprises the following formula:
  • R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are, independently, selected from H, F, C1-C6 alkyls and substituted C1-C6 alkyls, where M is selected from Si, Li, Be, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, hi, Sn, Sb, Te, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th
  • Preferred selections for R 2 , R 3 , R 5 and R 6 are methyl and ethyl.
  • Preferred selections for R 1 and R 4 are methyl, ethyl, propyl, and butyl.
  • Preferred selections for M are Ti, Zr, and Hf and, in such cases, v is selected from the integers 1, 2 and 3.
  • a specific example of a suitable multi-metallic molecular precursor is tri-(tert- butoxy)siloxy-tri(tert-butoxy)titanium ((tBuO) 3 Si-O-Ti(OtBu) 3 ), which can be used to deposit a titanium silicate (Ti-Si-O).
  • FIGS. 1A, IB and IC show various ways in which the multi-metallic molecular precursors can be utilized to deposit a homogeneous conformal film on a substrate.
  • FIGS. 1A, IB and IC show a simplified cross sectional schematic view of an ALD assembly 100.
  • the ALD assembly 100 comprises a deposition chamber 101. Positioned within the deposition chamber 101 is a substrate or wafer 102. It is on the surface of the wafer 102 that a homogenous conformal film 103 of desired thickness will be deposited.
  • Connected to the deposition chamber 101 are one or more supply lines for providing multi-metallic molecular precursor vapor 110, diluent gas 120 and reactant gas 130 to the deposition chamber 101.
  • the substrate 102 can be any material with a metallic or hydrophilic surface which is stable at the processing temperatures employed. Suitable materials will be readily evident to those of ordinary skill in the art.
  • Preferred substrates 102 include silicon wafers.
  • the substrate 102 may be pretreated to instill, remove, or standardize the chemical makeup and/or properties of the substrate's 102 surface.
  • silicon wafers form silicon dioxide on exposed surfaces. Silicon dioxide in small amounts is desirable because it attracts the metal precursor to the surface. However, in large quantities, silicon dioxide is undesirable. This is especially true if the layer being formed is intended to be a substitute for silicon dioxide. Accordingly, silicon dioxide on the surface of silicon wafers is often stripped away, for example, by treatment with hydrogen fluoride (HF) gas prior to film formation.
  • HF hydrogen fluoride
  • the multi-metallic molecular precursor vapor 110 comprises a vaporized compound having the formula (L 1 ) a M 1 GM 2 (L 2 ) b , wherein M 1 , M 2 , G, L 1 , L 2 , a and b are as previously described.
  • the compound is a liquid or solid at room temperature.
  • the compound may be dissolved in a solid.
  • the compound is, or is dissolved in, a liquid.
  • the precursor vapor 110 can be generated by direct vaporization of the solid or liquid compound in a vaporizer, with or without solvent, or by using a bubbler.
  • the diluent gas 120 can be any non-reactive gas or mixture of non-reactive gases, including any noble gas or gases.
  • Typical non-reactive gases include Ar, He, Ne, Xe, and N .
  • the reactant gas 130 can be any reducing agent or oxidizing agent or a mixture thereof.
  • the reactant gas 130 is reducing agent 130' and in FIG. IC the reactant gas 130 is oxidizing agent 130".
  • the reducing agent 130' or oxidizing agent 130" may be a gas or a liquid at room temperature but it is introduced to the deposition chamber 101 as a gas.
  • the nature of the reactant gas 130 is selected based on the nature of the multi- metallic film desired.
  • a multi-metallic film 103 is formed to a desired thickness on wafer 102 under conditions of ALD.
  • the multi-metallic molecular precursor gas 110 reacts with the reactant gas 130 (which may be oxidizer 130' or reducer 130") to form film 103.
  • the deposition chamber 101 is evacuated of gases and the wafer 102 is heated to a set deposition temperature.
  • the deposition temperature can range anywhere from approximately 100 °C to 600 °C, but is preferably from approximately 300 °C to 500 °C.
  • a steady flow of a diluent gas 120 e.g., Ar, He, Ne, Xe, or N 2 , is then introduced.
  • the pressure is raised by the introduction of the diluent gas 120 to a set process pressure, which can range anywhere from approximately 100 mTorr to 10 Torr, but is preferably from approximately 200 mTorr to 1.5 Torr.
  • the ALD cycle begins.
  • a pulse of the multi-metallic molecular precursor vapor 110 is introduced into the deposition chamber 101 by opening appropriate valves.
  • the vapor flow for the precursor gas 110 can range anywhere from approximately 1 seem to 1000 seem, but is preferably in the range of from approximately 5 seem to 100 seem.
  • the precursor vapor 110 can be diluted by diluent gas 120. In such cases, the flow rate for the diluent gas 120 can range anywhere from approximately 100 seem to 1000 seem.
  • the precursor vapor 110 can be generated using a bubbler or by direct vaporization of liquid or solid in a vaporizer.
  • the pulse time for the precursor gas 110 can range anywhere from approximately 0.01 s to 10 s, but is preferably in the range of from approximately 0.05 s to 2 s.
  • the flow of precursor vapor 110 into the chamber is terminated either by directing the flow of precursor vapor 110 into an exhaust line (for direct vaporization of the liquid) or by diverting the flow of precursor vapor 110 around the bubbler.
  • the deposition chamber 101 is purged for an appropriate time.
  • non-reactive gas 120 flows into the chamber 101 through the vapor delivery line.
  • the non-reacting diluent gas 120 can be He, Ne, Ar, Xe, or N 2 .
  • the amount of non-reacting gas 120 utilized in this step is preferably the same as the total flow of precursor gas 110 during the precursor vapor 110 pulse step.
  • the vapor purge time can be from approximately 0.1 s to 10 s but is preferably from approximately 0.5 s to 5 s.
  • the purge can be accomplished by pumping excess precursor gas 110 out of the chamber 101 in addition to, or in lieu of, pulsing non-reacting gas 120 into the chamber 101. Pumping generally entails the use vacuum or low pressure to cause evacuation.
  • a flow of reactant gas 130 is directed into the deposition chamber 101.
  • the reactant gas 130 is chosen depending on the desired material to be deposited and may, for example, be a reducing agent 130' or an oxidizing agent 130".
  • the flow of reactant gas 130 can range from approximately 100 seem to 2000 seem but is preferably in the range approximately 200 seem to 1000 seem.
  • the pulse time for the reactant gas 130 can range anywhere from 0.1 s to 10 s, but is preferably from 0.5 s to 3 s.
  • the chamber 101 is purged using a flow of non-reacting gas 120.
  • the non-reacting gas 120 can be He, Ne, Ar, Xe, or N 2 .
  • the purge flow for the non-reacting gas 120 is preferably the same as the total flow of reactant gas 130 through the reactant delivery line during the pulse of the reactant gas 130.
  • the purge can be accomplished by pumping excess reactant gas 130 out of the chamber 101 in addition to, or in lieu of, pulsing non-reacting gas 120 into the chamber 101.
  • the reactant gas 130 is chosen depending on the desired material to be deposited and may, for example, be a reducing agent 130' or an oxidizing agent 130". This is illustrated in more detail with reference to FIGS. 2A, 2B, 2C and 2D.
  • FIGS. 2A, 2B, 2C and 2D are identical with FIG. 1 with three exceptions.
  • the multi-metallic molecular precursor 210 has the following formula:
  • the reactant gases employed are a hydrogen source 231, an oxygen source 232, a nitrogen source 233 or a combination of a oxygen source 232 and nitrogen source 233, respectively.
  • the films deposited are a metallic alloy film 204, a multi-metallic oxide film 205, a multi-metallic nitride film 206 and a multi-metallic oxynitride film 207, respectively.
  • a metallic alloy film 204 is produced from pulses of precursor 210 and a hydrogen source 231.
  • Suitable hydrogen sources 231 include hydrogen (H 2 ) gas.
  • M 2 in the formula for precursor 210 is silicon, so the resultant film has the formula (M ⁇ Si) where M 1 is as previously defined. For example, if the metallic elements selected for M 1 and M 2 in
  • J5 the formula for precursor 210 are hafnium and silicon, respectively, then a hafnium silicide (Hf-Si) film is deposited. This process should work equally well if the B in the multi- metallic precursor is a covalent bond.
  • a multi-metallic oxide film 205 is produced from pulses of precursor 210 and an oxygen source 232.
  • Suitable oxygen sources 232 include but are not limited to atomic
  • Ozone is a preferred oxygen source due to its ability to react at lower temperatures and minimize the amount of contaminants in the resultant film.
  • Ozone is a preferred oxygen source due to its ability to react at lower temperatures and minimize the amount of contaminants in the resultant film.
  • M 2 in the formula for precursor 210 is silicon, so the resultant film has the formula (M'-Si-O) where M 1 is as previously defined.
  • the metallic elements selected for M 1 and M 2 in the formula for precursor 210 are hafnium and silicon, respectively, then a hafiiium silicate (Hf-Si-O) film is deposited. This method should work equally well if the B in the multi-metallic precursor is a covalent bond.
  • a multi-metallic nitride film 206 is produced from pulses of precursor 210 and a nitrogen source 233.
  • Suitable nitrogen sources include but are not limited to atomic nitrogen (N), nitrogen gas (N 2 ), ammonia (NH 3 ), hydrazine (H 2 NNH ), alkylhydrazine, alkylamine, and mixtures thereof.
  • M 2 in the formula for precursor 210 is silicon, so the resultant film has the formula (M'-Si-N) where M 1 is as previously defined.
  • the metallic elements selected for M 1 and M 2 in the formula for precursor 210 are tantalum and silicon, respectively, then a tantalum silicon nitride (Ta-Si-N) film is deposited.
  • Ta-Si-N tantalum silicon nitride
  • a multi-metallic oxynitride film 207 is produced from pulses of precursor 210, an oxygen source 232 and a nitrogen source 233. Suitable oxygen and nitrogen sources include those discussed above with reference to FIGS. 2B and 2C.
  • M 2 in the formula for precursor 210 is silicon, so the resultant film has the formula (M'-Si-O-N) where M 1 is as previously defined.
  • the metallic elements selected from M 1 and M 2 in the formula for precursor 210 are titanium and silicon, respectively, then a titanium silicon oxynitride (Ti-Si-O-N) film is deposited.
  • the multi-metallic molecular precursors of the instant invention may comprise more than two metallic elements.
  • multi-metallic molecular precursors having three and four metallic elements can be represented by the following respective formulae: and
  • M 1 , M 2 , L 1 , L 2 , a and b are as previously defined, where M 3 and M 4 are metallic elements which may be the same and/or may be identical to either M 1 or M 2 , where L 3 and L 4 are ligands, where c and d are selected from integers less than a valence number for M 3 and M 4 , respectively, and where G 1 , G 2 and G 3 are each, independently, selected from a single bond, double bond, bridging atom and bridging group.
  • M 3 and M 4 are metallic elements which may be the same and/or may be identical to either M 1 or M 2
  • L 3 and L 4 are ligands
  • c and d are selected from integers less than a valence number for M 3 and M 4 , respectively
  • G 1 , G 2 and G 3 are each, independently, selected from a single bond, double bond, bridging atom and bridging group.
  • Multi-metallic molecular precursors can be mixed with other multi-metallic and/or metallic precursors to create homogenous films with controlled ratios of metallic components.
  • a 50:50 mixture of (fBuO) 3 Si-O-Ti(OfBu) 3 and (tBuO) 3 Si-O- Si(OtBu) 3 should yield a homogenous film that contains a 4:1 ratio of silicon to titanium.
  • a 50:50 mixture of a 50:50 (tBuO) 3 Si-O-Ti(OtBu) 3 and (tBuO) 4 Si should yield a homogeneous film that contains a 3:1 ratio of silicon to titanium.
  • the precursors are mixed either in the solvent phase, prior to vaporization, or in the gas phase, after vaporization, and introduced to the deposition chamber simultaneously.
  • the use of similar or identical ligands facilitates the ability to dissolve the different precursors uniformly in a single solvent under similar conditions.
  • the multi-metallic molecular precursors can be utilized in an ALD process that introduce other precursors in separate pulses. This is not a preferred embodiment, as it fails to embrace the full benefit of the invention which permits the precursor introduction to be consolidated into a single step. Nonetheless, the use of multi-metallic molecular precursors in any ALD process will consolidate the number of pulses necessary and further the homogeneity of the resultant film. Accordingly, ALD processes that introduce other precursors in separate pulses are also embraced if they utilize a multi-metallic molecular precursor. Multi-Metallic Molecular Precursor Cocktails
  • a second ALD method for forming a multi- metallic film on a substrate comprises at least one cycle that comprises the step of introducing a mixture of metallic molecular precursor gases into a deposition chamber that contains the substrate.
  • the second ALD method comprises at least one cycle that comprises the following steps: (i) introducing a mixture of at least two different metallic molecular precursors to a deposition chamber; (ii) purging the deposition chamber; (iii) introducing a reactant gas to the deposition chamber; and (iv) purging the deposition chamber.
  • This embodiment of the method is visually illustrated by FIG. 3. In FIG. 3 is identical to FIG.
  • a vapor mixture of metallic precursors 310 is utilized instead of a multi-metallic molecular precursor vapor 110.
  • the steps in the second method are the same as those employed in the first method with the exception that a vapor mixture of metallic precursors 310 is utilized in the first step of the cycle rather than a multi-metallic molecular precursor 110.
  • Each metallic precursor contains, within its molecules, a metallic element required to make the desired film.
  • the metallic precursors in the mixture have the following formulae:
  • M and M are different metallic elements, where each L and L a ligand and may be the same or different and where w and z are integers less than or equal to a valence number for M and M , respectively.
  • M 1 and M 2 can be any metallic element as long as M 1 and M 2 are not identical.
  • Preferred metallic elements for use as M 1 and M 2 include Si, Li, Be, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, TI, Pb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th.
  • each L 1 and L 2 is selected, independently, from ligands and may be the same or different.
  • Suitable ligands are readily ascertainable by those of ordinary skill in the art and include those ligands known to be useful in precursors for ALD processes. Undesirable ligands are removed during the course of film deposition due to their relatively weak chemical bonds.
  • Preferred ligands include but are not limited to a double bonded nitrogen, alkyls, alkoxides, halides, hydrides, amides, imides, azides, nitrates, cyclopentadienyls, carbonyls, carboxylates, diketonates, as well as substituted analogs thereof and combinations thereof. It is preferable, but not necessary to use relatively small ligands having, e.g., 1-12 atoms.
  • ligands that contain small relatively small ligands tend to volatilize more readily at lower temperatures than compounds that contain relatively larger ligands. Furthermore, compounds that contain relatively smaller ligands tend to be more stable.
  • w and z are integers less than or equal to a valence number for M 1 and M 2 , respectively.
  • either at least one of w and z is an integer one less than a valence number for metallic element due to the presence of a double bond between one of the ligands and the metallic element.
  • w and z are integers equal to a valence number for their respective metallic elements.
  • w and z are selected, independently, from 1, 2, 3 and 4.
  • the precursor vapors 310 can be mixed in the deposition zone, or a mixture of precursor gases 310 can be delivered to the deposition zone by direct liquid injection (DLI) of a mixture of precursors in liquid phase.
  • DLI direct liquid injection
  • the liquid precursors are vaporized in a separate vaporization step.
  • the vapor of the individual precursors is mixed in the delivery manifold and deposition chamber 101 during the precursor pulse step, h another embodiment an alternating precursor pulse sequence is used.
  • the diluent gas 120 can be any non-reactive gas or mixture of non-reactive gases, including any noble gas or gases.
  • Typical non-reactive gases include Ar, He, Ne, Xe, and N 2 .
  • the reactant gas 130 can be any reducing agent or oxidizing agent or a mixture thereof.
  • the reactant gas 130 is reducing agent 130' and in FIG. IC the reactant gas 130 is oxidizing agent 130".
  • the reducing agent 130' or oxidizing agent 130" may be a gas or a liquid at room temperature but it is introduced to the deposition chamber 101 as a gas.
  • the nature of the reactant gas 130 is selected based on the nature of the multi- metallic film desired. Suitable reactant gases 130 include hydrogen sources, oxygen sources and or nitrogen sources.
  • the mixture of precursors is a mixture of the two compounds M(NR 8 R 9 ) q and Si(NR I0 R n ) 2 where R 8 , R 9 , R 10 and R 11 are, independently, selected from H, F, C1-C6 alkyls, and substituted C1-C6 alkyls, where M is selected from Si, Li, Be, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, TI, Pb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th, and q is less than or equal to a valence
  • This cocktail is especially useful for depositing a tantalum silicon nitride layer.
  • the precursor cocktail is a mixture of Hf(NR 12 R 13 ) 4 and Si(NR 14 R I5 ) 4 , where R 12 , R 13 , R 14 and R 15 are selected from methyl and ethyl groups.
  • This mixture can be used to deposit a number of different halfnium-silicon films depending on the nature of the reactant utilized. For example, if the reactant is an oxygen source, then the multi-component film will be a hafnium silicate (Hf-Si-O) film. Alternatively, if the reactant is a nitrogen source, a hafnium silicon nitride (Hf-Si-N) film will be formed.
  • the resultant film will be a hafnium oxynitride (Hf-Si-O-N) film.
  • a hafnium silicon alloy (Hf-Si) film will be formed. Suitable oxygen sources, nitrogen sources, and hydrogen sources are identical to those identified previously.
  • the mixture can range anywhere from 10:1 to 1: 10 by volume and the vapor flow rate can range anywhere from approximately 0.01 g/min to 10 g/min.
  • the oxidizer is ozone, which is preferred, the total O 2 /O 3 flow can range anywhere from approximately 100 seem to 1000 seem and the ozone concentration can range anywhere from 1% to 20% by volume.
  • the process pressure can range anywhere from approximately 50 mTorr to 10 Torr and the substrate temperature can range anywhere from approximately 200 °C to 600 °C, with the preferred substrate temperature being from approximately 300 °C to 400 °C.
  • the dilution gas flow rate can range anywhere from approximately 100 seem to 2000 seem, but preferably ranges from approximately 500 seem to 2000 seem.
  • a specific example of a mixture of precursors for deposition of HfSiO films using a cocktail comprising Hf(NR 12 R 13 ) 4 and Si(NR 14 R 15 ) 4 is the case where R 12 and R 14 are methyl and R 13 and R 15 are ethyl.
  • the resulting hafnium and silicon precursors are tetrakis(ethylmethylamino) hafnium (i.e., TEMAHf) and tetrakis(ethylmethylamino) silicon (i.e., TEMASi).
  • TEMAHf tetrakis(ethylmethylamino) hafnium
  • TEMASi tetrakis(ethylmethylamino) silicon
  • Ozone was used as an oxygen source for depositing the metal oxide films.
  • Various precursor mixtures were used, ranging from a 99:1 HfiSi molar ratio mixture to a 1:99 HfiSi molar ratio mixture, hi this example, the liquid flow rate can range from approximately 0.01 to 1 g/min, but the flow rate is preferably in the range approximately 0.02 to 0.1 g/min.
  • the oxygen flow can range from approximately 100 seem to 1000 seem.
  • the deposition temperature can range from approximately 250 °C to 450 °C. Using a flow rate of 0.04 g/min and an oxygen flow of 300 seem with 12% by volume O 3 at temperatures from 300 °C to 450 °C it is possible to obtain HfSiO films with varying composition (see Table 1 below).
  • FIG. 4 A transmission electron microscope cross section image of 45A Hfo. 58 Si 0 . 2 O 2 is shown in FIG. 4 for the HfSiO film deposited at 400°C.
  • a polysilicon cap layer was also deposited followed by a thermal anneal at 700°C for 30 s. The amorphous state of the film was maintained after the anneal with an interfacial oxide layer thickness of approximately 7A.
  • ALD depositions embraced by these methods include thermal ALD, photo-assisted ALD, laser assisted ALD, plasma-assisted ALD and radical assisted ALD.

Abstract

Atomic layer deposition methods for depositing conformal homogeneous multi-component films on substrates are provided. In one method, a pulse of multi-metallic molecular precursor is introduced into a deposition chamber where a substrate is located. The multi-metallic molecular precursor contains the metallic elements necessary to form a mono-layer of the multi-metallic film. In another method, a mixture of two or more metallic precursors is pulsed into a deposition chamber where a substrate is located. The mixture of metallic precursors contains the metallic elements necessary to form a mono-layer of the multi-metallic film. In both methods, subsequent reactants are pulsed into the chamber to convert the precursors into the desired mono-layer. The cycle is repeated as many times as necessary to achieve a film of desired thickness. Illustrative films that may be formed by these processes include metallic alloy films, multi-metallic oxide films, multi-metallic nitride films and multi-metallic oxynitride films. By introducing the multiple metallic components in a single pulse in per cycle, throughput is increased. In addition, by introducing the multiple metallic components in a single pulse, a homogeneous film is formed that does not require subsequent annealing.

Description

MOLECULAR LAYER DEPOSITION OF THIN FILMS WITH MIXED COMPONENTS
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to, and claims priority to, United States Provisional Patent Application No. 60/397,029, entitled Molecular Layer Deposition Of Thin Films With Mixed Components, filed July 18, 2002, the entire disclosure of which is hereby incorporated by reference.
FIELD OF THE INVENTION The present invention relates to the field of semiconductors. More specifically, the present invention relates to the atomic layer deposition (ALD) of thin conformal homogeneous multi-metallic films onto semiconductor devices and wafers.
BACKGROUND OF THE INVENTION
The next generation of semiconductor devices will require thinner dielectric films for metal-oxide-silicon (MOS) transistor gates and capacitor dielectrics. However, as oxides are scaled down, the tunneling leakage current becomes more significant and limits the useful range for gate oxides to a thickness of about 1.8 nm or more. Accordingly, extensive research is being done to identify high-k materials that, when made ultra-thin, provide the dielectric properties of silicon dioxide minus the leakage.
Thin multi-metallic films are of increasing interest in the microelectronic industry. For example, hafnium silicate (Hf-Si-O) films are considered a possible alternative gate oxide film to silicon oxide (Si-O) films. Similarly, tantalum silicon nitride (Ta-Si-N) films are reported to have better properties than tantalum nitride (TaN) films as a barrier for copper interconnect.
Current deposition techniques for forming films onto semiconductor devices and wafers include chemical vapor deposition (CVD). In CVD, two or more reactant gases are mixed together in a deposition chamber where the gases either react in the gas phase and precipitate a film onto a substrate's surface or react directly on the substrate's surface. Deposition by CVD occurs for a specified length of time, based on the desired thickness of the deposited film. Since the specified time is a function of the flux of reactants into the chamber, the required time may vary from chamber to chamber. CVD is increasingly unable to meet the requirements for making advanced thin films.
CVD requires high processing temperatures and makes inefficient use of reactants. In addition, CVD results in the presence of a relatively high level of impurities in the resultant film. Finally, CVD is limited in its ability to deposit ultra-thin homogeneous conformal films for high k gate dielectrics onto wafers. Atomic layer deposition (ALD) is an alternative to traditional CVD for depositing thin films, i a conventional ALD deposition cycle, each reactant gas is introduced sequentially into the chamber, so that no gas phase intermixing occurs. A monolayer of a first reactant (i.e., precursor) is physi- or chemisorbed onto the substrate's surface. Excessive first reactant is then evacuated, usually with the aid of an inert purge gas and/or pumping. A second reactant is then introduced to the deposition chamber and reacts with the first reactant to form a mono-layer of the desired film through a self-limiting surface reaction. The self-limiting reaction stops once the initially adsorbed first reactant fully reacts with the second reactant. Excessive second reactant is evacuated usually with the aid of an inert purge gas and/or pumping. A desired film thickness is obtained by repeating the deposition cycle as necessary. The film thickness can be controlled to atomic layer (i.e., angstrom scale) accuracy by counting the number of deposition cycles.
ALD has several advantages over traditional CVD. First, ALD can be performed at lower temperatures. Second, ALD can produce ultra-thin conformal films. In fact, ALD can control film thickness on an atomic scale and be used to "nano-engineer" complex thin films. Third, ALD provides conformal coverage of thin films on non-planar substrates. However, one problem with conventional ALD processes is the low throughput that results from long cycle times. Conventional ALD processes perform a relatively slow "layer- by layer" growth using alternating doses of precursor and reactant. This problem is exacerbated when the deposited film is a multi-metallic film, since multiple precursors are employed. The deposition rate of multi-metallic films is typically less than 1 A per cycle. To be useful in semiconductor manufacturing, an ALD process must demonstrate an acceptable throughput.
Another difficulty in the production of multi-metallic films using conventional ALD processes is the non-homogeneity of the resultant film. Homogenous films are desired, for example, in MOS device applications. Conventional ALD processes, due to the use of alternating doses of chemical sources, form films that are a series of phase separated nano- laminates. Subsequent high temperature annealing is required to inter-diffuse the multiple elements to form a homogeneous composition. Accordingly, there is a significant need in the industry for further developments.
SUMMARY OF THE INVENTION
The present invention provides new ALD methods for depositing conformal homogeneous multi-metallic films onto substrates. Films that may be deposited by the ALD method of the present invention include metallic alloy films, multi-metallic oxide films, multi-metallic nitride films, and multi-metallic oxynitride films. ALD depositions embraced by the method of the present invention include thermal ALD, photo-assisted ALD, laser assisted ALD, plasma-assisted ALD and radical assisted ALD.
A first ALD method for forming a multi-metallic film on a substrate comprises at least one cycle that comprises the step of introducing a multi-metallic molecular precursor gas into a deposition chamber that contains the substrate. Preferably, the multi-metallic molecular precursor comprises all of the metallic elements necessary to make a homogeneous mono-layer of the film. By introducing the metallic elements in a single pulse per cycle, as part of a single precursor, the metallic elements are mixed uniformly on a molecular level and the need to for alternate doses of multiple precursors is eliminated. One example of a multi- metallic molecular precursor is tri-(tert-butoxy)siloxy-tri(tert-butoxy)titanium - (tBuO)3Si-O- Ti(OtBu)3 - which can be used to deposit titanium silicate (Ti-Si-O) films when the subsequent reactant is an oxygen source.
In one embodiment, the first ALD method includes at least one cycle that comprises the following steps: (i) introducing a multi-metallic molecular precursor gas into a deposition chamber that contains a substrate; (ii) purging the deposition chamber; (iii) introducing one or more reactant gases to the deposition chamber; and (iv) purging the deposition chamber. By this method, the multi-metallic molecular precursor is physi-or chemisorbed onto the substrate's surface and the subsequent reactant cleaves any undesirable ligands from the precursor, leaving a mono-layer of the desired multi-metallic film. The reactant can be any oxidizing or reducing agent or mixture thereof and is selected to convert the physi-or chemisorbed precursor into the type of multi-metallic film desired. Each time the cycle is repeated, another mono-layer is added. In this manner, a conformal homogeneous film of the desired thickness and composition can be nano-engineered.
In another aspect of the invention, a second ALD method is provided for forming a multi-metallic film on a substrate comprising at least one cycle that comprises the step of introducing a mixture of metallic molecular precursor gases into a deposition chamber that contains the substrate. Preferably, the mixture of precursors comprises all of the metallic elements necessary to make a homogeneous mono-layer of the film. By introducing the metallic elements in a single pulse per cycle, as part of a cocktail of precursors, the metallic elements are mixed uniformly on a molecular level and the need to for alternate doses of multiple precursors is eliminated. One example of a suitable precursor cocktail is a mixture of the two compounds Hf(NEtMe)2 and Si(NEtMe)2 - which can be used to deposit hafnium silicate (Hf-Si-O) films when the subsequent reactant is an oxygen source.
In one embodiment, the first ALD method comprises at least one cycle that comprises the following steps: (i) introducing a mixture of at least two different metallic molecular precursors to a deposition chamber; (ii) purging the deposition chamber; (iii) introducing a reactant gas to the deposition chamber; and (iv) purging the deposition chamber. By this method, the mixture, or cocktail, of metallic molecular precursors is first physi- or chemisorbed onto the substrate's surface and the subsequent reactant cleaves any undesirable ligands from the precursors, leaving a mono-layer of the desired multi-metallic film. Once again, the reactant can be any oxidizing or reducing agent or combination thereof and is selected to convert the physi- or chemisorbed precursors into the type of multi-metallic film desired. Each time the cycle is repeated, another mono-layer is added. In this manner, a conformal homogeneous film of the desired thickness and composition can be nano- engineered. Both methods permit all of the metallic elements necessary to make the multi-metallic film to be supplied in a single dose, or pulse, in each deposition cycle. Thus, the inventions provide several benefits. First, the inventions significantly reduce ALD process cycle time and, thereby, increase throughput. Second, the inventions form homogeneous films as- deposited, which eliminates the need for subsequent annealing. Third, the inventions increase efficiency by reducing the number of particles generated in the gas phase during the film deposition process.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is described in detail below and with reference to the following figures, in which: FIGS. 1A, IB and 1C illustrate schematic diagrams of an ALD systems and method according to various embodiments of the present invention;
FIGS. 2A, 2B, 2C and 2D also illustrates ALD systems and methods according to additional embodiments of the present invention;
FIG. 3 illustrates a schematic diagram of an ALD system and method of the present invention; and
FIG. 4 is a TEM cross section image of a 45 A Hfo.58Sio. 2O film made in accordance with one of the ALD methods of the present invention.
DETAILED DESCRIPTION OF THE INVENTION Definitions "Metal" as used herein is an element selected the following elements in the periodic table: Li; Be; Na; Mg; Al; K; Ca; Sc; Ti; V; Cr; Mn; Fe; Co; Ni; Cu; Zn; Ga; Ge; Rb; Sr; Y; Zr; Nb; Mo; Tc; Ru; Rh; Pd; Ag; Cd; In; Sn; Sb; Cs; Ba; La; Hf; Ta; W; Re; Os; Ir; Pt; Au Hg; Tl; Pb; Bi; Po; Fr; Ra; Ac; Ce; Pr; Nd; Pm; Sm; Eu; Gd; Tb; Dy; Ho; Er; Tm; Yb; Lu
Th; Pa; U; Np; Pu; Am; Cm; Bk; Cf; Es; Fm; Md; No; and Lr. "Metalloid" as used herein is an element selected from the following elements in the periodic table: B; Si; Ge; As; Sb; Te and At.
"Metallic" as used herein indicates the presence of at least one element selected from metals and metalloids as defined above. "Multi-metallic" as used herein indicates the presence of two or more elements selected from metals and metalloids as defined above.
"Molecular precursor" as used herein is a reactant used to introduce atoms or chemical groups onto a substrate to form a film. The molecular precursor is physi- or chemisorbed onto the surface of a substrate and must be modified by a subsequent reactant or reactants to produce the desired film.
"Metallic molecular precursor" as used herein is a molecular precursor that contains at least one element selected from metals and metalloids as defined above.
"Multi-metallic molecular precursor" as used herein is a molecular precursor that contains at least two elements selected from metals and metalloids as defined above. "Leaving groups" and "ligands," as used interchangeably herein, refer to atoms or chemical groups in a metallic molecular precursor that are attached, covalently or non- covalently, to the metallic components therein.
"Hydrogen source" means any compound that contains within its structure reactive hydrogen and includes but is not limited to hydrogen gas and the like. "Oxygen source" means any compound that contains within is structure a reactive oxygen including but not limited to atomic oxygen, oxygen gas, ozone, water, alcohols, hydrogen peroxide and the like.
"Nitrogen source" means any compound that contains within its structure a reactive nitrogen and includes but is not limited to atomic nitrogen, nitrogen gas, ammonia, hydrazine, alkylhydrazine, alkylamine and the like.
"Multi-metallic film" as used herein is any film whose components, not counting any contaminants, includes two or more elements selected from metals and metalloids as defined above. Illustrative multi-metallic films include but are not limited to metallic alloy films, multi-metallic oxide films, multi-metallic nitride films and multi-metallic oxynitride films. "Metallic alloy film" as used herein is a film formed principally from metal and/or metalloid elements as defined above. "Oxide film" as used herein is a film formed principally from oxygen and at least one type of metal or metalloid as defined above.
"Nitride film" as used herein is a film formed principally from nitrogen and at least one type of metal or metalloid as defined above. "Oxynitride film" as used herein is a film formed principally from oxygen, nitrogen, and at least one type of metal or metalloid as defined above.
Overview
In one aspect of the present invention, a multi-metallic molecular precursor is utilized in an ALD process to deposit conformal homogeneous multi-metallic films onto substrates. In another aspect, a mixture, or cocktail, of two or more metallic molecular precursors is utilized in an ALD process to deposit conformal homogeneous multi-metallic films onto substrates. Preferably, in both embodiments, all of the metallic elements necessary to make the multi-metallic films are introduced in a single dose or pulse in each deposition cycle.
Accordingly, the present invention eliminates the need to alternate pulses of two or more metallic precursors and, thereby, increases throughput. Furthermore, the present invention generates a homogeneous film as deposited, thereby eliminating the need to subsequently anneal the film. The invention reduces the particles generated in the gas phase during the film deposition, among other advantages.
Multi-Metallic Molecular Precursor Compounds A first ALD method for forming multi-metallic films on a substrate comprises at least one cycle that comprises the step of introducing a multi-metallic molecular precursor gas into a deposition chamber that contains a substrate. In one embodiment, the method for forming multi-metallic films on a substrate comprises at least one cycle that comprises the following steps: (i) introducing a multi-metallic molecular precursor gas into a deposition chamber that contains a substrate; (ii) purging the deposition chamber; (iii) introducing one or more reactant gases to the deposition chamber; and (iv) purging the deposition chamber.
The multi-metallic molecular precursor contains, within each molecule, the different metallic elements required to make the desired film. In one embodiment, the multi-metallic molecular precursor comprises the following formula: (L'^GM^b where M1 and M2 are different metallic elements, where each L1 and L2 is a leaving group (ligand) and may be the same or different, where a and b are integers less than a valence number for M1 and M2, respectively, and where G is selected from a single bond, double bond, bridging atom and bridging group. M1 and M2 can be any metallic element as long as M1 and M2 are not identical.
Preferred metallic elements for use as M1 and M2 include Si, Li, Be, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th. G can be a single bond, double bond, bridging atom or bridging group. Preferred selections for G include a single bond (-), an oxygen bridge (-O-), a nitrogen bridge (-N=), a secondary or tertiary amine bridge (-NRS-), a sulfur bridge (-S-) and a secondary or tertiary phosphorous bridge (-PRS), where Rs is can be hydrogen or any known substituent. Preferably, Rs is selected from hydrogen and C1-C6 alkyls. L1 and L2 is selected, independently, from ligands and may be the same or different.
Suitable ligands are readily ascertainable by those of ordinary skill in the art and include those ligands known to be useful in precursors for ALD processes. Undesirable ligands are removed during the course of film deposition due to their relatively weak chemical bonds. Preferred ligands include alkyls, alkoxides, halides, hydrides, amides, imides, azides, nitrates, cyclopentadienyls, carbonyls, carboxylates, diketonates, as well as substituted analogs thereof and combinations thereof. It is preferable, but not necessary to use relatively small ligands having, e.g., 1-12 atoms. Compounds that contain small relatively small ligands tend to volatilize more readily at lower temperatures than compounds that contain relatively larger ligands. Specific preferred ligands include dimethylamide (-N(CH3)2), diethylamide (- N(CH2CH3)2), methylethylamide (-N(CH3)(CH2CH3))5 methoxide (-OCH3), ethoxide (- OCH2CH3), and butoxide (-O(CH2)3CH3).
Variables a and b are integers less than a valence number for M1 and M2, respectively. Preferably, a an b are integers one less than a valence number for M1 and M2, respectively. More preferably, a and b are selected, independently, from 1, 2 and 3. In one embodiment, the multi -metallic precursor comprises the following formula:
(RO)x(R > 2-Rr, 3JN)3-xSi-O-M(OR4)y(NR 5:) DR60)v. where R1, R2, R3, R4, R5 and R6 are, independently, selected from H, F, C1-C6 alkyls and substituted C1-C6 alkyls, where M is selected from Si, Li, Be, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, hi, Sn, Sb, Te, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th, where x is selected from 1, 2 and 3, where y is an integer less than or equal to v and where v is an integer one less than a valance number for M. Preferred selections for R2, R3, R5 and R6 are methyl and ethyl. Preferred selections for R1 and R4 are methyl, ethyl, propyl, and butyl. Preferred selections for M are Ti, Zr, and Hf and, in such cases, v is selected from the integers 1, 2 and 3. A specific example of a suitable multi-metallic molecular precursor is tri-(tert- butoxy)siloxy-tri(tert-butoxy)titanium ((tBuO)3Si-O-Ti(OtBu)3), which can be used to deposit a titanium silicate (Ti-Si-O).
FIGS. 1A, IB and IC show various ways in which the multi-metallic molecular precursors can be utilized to deposit a homogeneous conformal film on a substrate. FIGS. 1A, IB and IC show a simplified cross sectional schematic view of an ALD assembly 100. The ALD assembly 100 comprises a deposition chamber 101. Positioned within the deposition chamber 101 is a substrate or wafer 102. It is on the surface of the wafer 102 that a homogenous conformal film 103 of desired thickness will be deposited. Connected to the deposition chamber 101 are one or more supply lines for providing multi-metallic molecular precursor vapor 110, diluent gas 120 and reactant gas 130 to the deposition chamber 101.
The substrate 102 can be any material with a metallic or hydrophilic surface which is stable at the processing temperatures employed. Suitable materials will be readily evident to those of ordinary skill in the art. Preferred substrates 102 include silicon wafers. The substrate 102 may be pretreated to instill, remove, or standardize the chemical makeup and/or properties of the substrate's 102 surface. For example, silicon wafers form silicon dioxide on exposed surfaces. Silicon dioxide in small amounts is desirable because it attracts the metal precursor to the surface. However, in large quantities, silicon dioxide is undesirable. This is especially true if the layer being formed is intended to be a substitute for silicon dioxide. Accordingly, silicon dioxide on the surface of silicon wafers is often stripped away, for example, by treatment with hydrogen fluoride (HF) gas prior to film formation. A thin standardized silicon dioxide surface layer, only a few A thick, is then reintroduced prior to film formation by standard oxidation methods, for example, by exposure to ozone.
The multi-metallic molecular precursor vapor 110 comprises a vaporized compound having the formula (L1)aM1GM2(L2)b, wherein M1, M2, G, L1, L2, a and b are as previously described. The compound is a liquid or solid at room temperature. The compound may be dissolved in a solid. Preferably, the compound is, or is dissolved in, a liquid. The precursor vapor 110 can be generated by direct vaporization of the solid or liquid compound in a vaporizer, with or without solvent, or by using a bubbler.
The diluent gas 120 can be any non-reactive gas or mixture of non-reactive gases, including any noble gas or gases. Typical non-reactive gases include Ar, He, Ne, Xe, and N .
The reactant gas 130 can be any reducing agent or oxidizing agent or a mixture thereof. Thus, in FIG. IB, the reactant gas 130 is reducing agent 130' and in FIG. IC the reactant gas 130 is oxidizing agent 130". The reducing agent 130' or oxidizing agent 130" may be a gas or a liquid at room temperature but it is introduced to the deposition chamber 101 as a gas. The nature of the reactant gas 130 is selected based on the nature of the multi- metallic film desired.
In FIGS. 1A, IB and IC, a multi-metallic film 103 is formed to a desired thickness on wafer 102 under conditions of ALD. The multi-metallic molecular precursor gas 110 reacts with the reactant gas 130 (which may be oxidizer 130' or reducer 130") to form film 103.
More specifically, when wafer 102 is placed in deposition chamber 101, the deposition chamber 101 is evacuated of gases and the wafer 102 is heated to a set deposition temperature. The deposition temperature can range anywhere from approximately 100 °C to 600 °C, but is preferably from approximately 300 °C to 500 °C. A steady flow of a diluent gas 120, e.g., Ar, He, Ne, Xe, or N2, is then introduced. The pressure is raised by the introduction of the diluent gas 120 to a set process pressure, which can range anywhere from approximately 100 mTorr to 10 Torr, but is preferably from approximately 200 mTorr to 1.5 Torr. After a steady state pressure has been achieved and after sufficient time has been provided to allow residual gases to be evacuated from the surface of the wafer, the ALD cycle begins. In the first step, a pulse of the multi-metallic molecular precursor vapor 110 is introduced into the deposition chamber 101 by opening appropriate valves. The vapor flow for the precursor gas 110 can range anywhere from approximately 1 seem to 1000 seem, but is preferably in the range of from approximately 5 seem to 100 seem. The precursor vapor 110 can be diluted by diluent gas 120. In such cases, the flow rate for the diluent gas 120 can range anywhere from approximately 100 seem to 1000 seem. The precursor vapor 110 can be generated using a bubbler or by direct vaporization of liquid or solid in a vaporizer. The pulse time for the precursor gas 110 can range anywhere from approximately 0.01 s to 10 s, but is preferably in the range of from approximately 0.05 s to 2 s. At the end of the pulse, the flow of precursor vapor 110 into the chamber is terminated either by directing the flow of precursor vapor 110 into an exhaust line (for direct vaporization of the liquid) or by diverting the flow of precursor vapor 110 around the bubbler.
In the second step, the deposition chamber 101 is purged for an appropriate time. Preferably, during the purge, non-reactive gas 120 flows into the chamber 101 through the vapor delivery line. For example, the non-reacting diluent gas 120 can be He, Ne, Ar, Xe, or N2. The amount of non-reacting gas 120 utilized in this step is preferably the same as the total flow of precursor gas 110 during the precursor vapor 110 pulse step. The vapor purge time can be from approximately 0.1 s to 10 s but is preferably from approximately 0.5 s to 5 s. Alternatively, the purge can be accomplished by pumping excess precursor gas 110 out of the chamber 101 in addition to, or in lieu of, pulsing non-reacting gas 120 into the chamber 101. Pumping generally entails the use vacuum or low pressure to cause evacuation.
In the third step, at the end of the vapor purge, a flow of reactant gas 130 is directed into the deposition chamber 101. The reactant gas 130 is chosen depending on the desired material to be deposited and may, for example, be a reducing agent 130' or an oxidizing agent 130". The flow of reactant gas 130 can range from approximately 100 seem to 2000 seem but is preferably in the range approximately 200 seem to 1000 seem. The pulse time for the reactant gas 130 can range anywhere from 0.1 s to 10 s, but is preferably from 0.5 s to 3 s.
In the fourth and final step of the cycle, after the pulse of the reactant gas 130 is completed, the chamber 101 is purged using a flow of non-reacting gas 120. For example, the non-reacting gas 120 can be He, Ne, Ar, Xe, or N2. The purge flow for the non-reacting gas 120 is preferably the same as the total flow of reactant gas 130 through the reactant delivery line during the pulse of the reactant gas 130. Alternatively, the purge can be accomplished by pumping excess reactant gas 130 out of the chamber 101 in addition to, or in lieu of, pulsing non-reacting gas 120 into the chamber 101.
This completes one cycle in the ALD process and generates a conformal
5 homogeneous mono-layer of the desired film. The cycle is then repeated as many times as necessary to achieve the desired film thickness.
As stated, the reactant gas 130 is chosen depending on the desired material to be deposited and may, for example, be a reducing agent 130' or an oxidizing agent 130". This is illustrated in more detail with reference to FIGS. 2A, 2B, 2C and 2D.
L0 FIGS. 2A, 2B, 2C and 2D are identical with FIG. 1 with three exceptions. First, the multi-metallic molecular precursor 210 has the following formula:
(R1O)u(R2R3N)t-uM1-O-M2(OR4)y(NR5R6)v-y, where M1, M2, R1, R2, R3, R4, R5, R6, v and y are as previously defined, where u is an integer less than or equal to t and where t is an integer one less than a valence number for M1.
[5 Second, the reactant gases employed are a hydrogen source 231, an oxygen source 232, a nitrogen source 233 or a combination of a oxygen source 232 and nitrogen source 233, respectively. Third, the films deposited are a metallic alloy film 204, a multi-metallic oxide film 205, a multi-metallic nitride film 206 and a multi-metallic oxynitride film 207, respectively. 0 In FIG. 2A, a metallic alloy film 204 is produced from pulses of precursor 210 and a hydrogen source 231. Suitable hydrogen sources 231 include hydrogen (H2) gas. Each cycle in this process deposits a mono-layer of metallic alloy film 204. In one embodiment, M2 in the formula for precursor 210 is silicon, so the resultant film has the formula (M^Si) where M1 is as previously defined. For example, if the metallic elements selected for M1 and M2 in
J5 the formula for precursor 210 are hafnium and silicon, respectively, then a hafnium silicide (Hf-Si) film is deposited. This process should work equally well if the B in the multi- metallic precursor is a covalent bond.
In FIG. 2B, a multi-metallic oxide film 205 is produced from pulses of precursor 210 and an oxygen source 232. Suitable oxygen sources 232 include but are not limited to atomic
(0 oxygen (O), oxygen gas (O2), ozone (O3), steam (H2O), hydrogen peroxide (H2O2), alcohols, nitric oxide (NO) and nitrous oxide (N2O). Ozone is a preferred oxygen source due to its ability to react at lower temperatures and minimize the amount of contaminants in the resultant film. Each cycle deposits a mono-layer of oxide film 205. In one embodiment, M2 in the formula for precursor 210 is silicon, so the resultant film has the formula (M'-Si-O) where M1 is as previously defined. For example, if the metallic elements selected for M1 and M2 in the formula for precursor 210 are hafnium and silicon, respectively, then a hafiiium silicate (Hf-Si-O) film is deposited. This method should work equally well if the B in the multi-metallic precursor is a covalent bond.
In FIG. 2C, a multi-metallic nitride film 206 is produced from pulses of precursor 210 and a nitrogen source 233. Suitable nitrogen sources include but are not limited to atomic nitrogen (N), nitrogen gas (N2), ammonia (NH3), hydrazine (H2NNH ), alkylhydrazine, alkylamine, and mixtures thereof. In one embodiment, M2 in the formula for precursor 210 is silicon, so the resultant film has the formula (M'-Si-N) where M1 is as previously defined. For example, if the metallic elements selected for M1 and M2 in the formula for precursor 210 are tantalum and silicon, respectively, then a tantalum silicon nitride (Ta-Si-N) film is deposited. This method should work equally well if the B in the multi-metallic precursor is a covalent bond or a secondary or tertiary amine.
In FIG. 2D, a multi-metallic oxynitride film 207 is produced from pulses of precursor 210, an oxygen source 232 and a nitrogen source 233. Suitable oxygen and nitrogen sources include those discussed above with reference to FIGS. 2B and 2C. In one embodiment, M2 in the formula for precursor 210 is silicon, so the resultant film has the formula (M'-Si-O-N) where M1 is as previously defined. For example, if the metallic elements selected from M1 and M2 in the formula for precursor 210 are titanium and silicon, respectively, then a titanium silicon oxynitride (Ti-Si-O-N) film is deposited.
The multi-metallic molecular precursors of the instant invention may comprise more than two metallic elements. For example, multi-metallic molecular precursors having three and four metallic elements can be represented by the following respective formulae:
Figure imgf000014_0001
and
(L1)aM1G1M2(L2)bG2M3(L3)cG3M4(L4)d where M1, M2, L1, L2, a and b are as previously defined, where M3 and M4 are metallic elements which may be the same and/or may be identical to either M1 or M2, where L3 and L4 are ligands, where c and d are selected from integers less than a valence number for M3 and M4, respectively, and where G1, G2 and G3 are each, independently, selected from a single bond, double bond, bridging atom and bridging group. In general, however, as the precursor becomes larger it is harder to keep in solution and vaporize. Furthermore, as the precursor gets larger, its stability becomes a bigger concern. Accordingly, it is preferable to use multi- metallic precursors that contain only two metallic elements.
Multi-metallic molecular precursors can be mixed with other multi-metallic and/or metallic precursors to create homogenous films with controlled ratios of metallic components. For example, a 50:50 mixture of (fBuO)3Si-O-Ti(OfBu)3 and (tBuO)3Si-O- Si(OtBu)3 should yield a homogenous film that contains a 4:1 ratio of silicon to titanium. Alternatively, a 50:50 mixture of a 50:50 (tBuO)3Si-O-Ti(OtBu)3 and (tBuO)4Si should yield a homogeneous film that contains a 3:1 ratio of silicon to titanium. Preferably, in such embodiments, the precursors are mixed either in the solvent phase, prior to vaporization, or in the gas phase, after vaporization, and introduced to the deposition chamber simultaneously. In addition, it is preferable in such embodiments to select similar, and even more preferably identical, ligands for the different precursors. The use of similar or identical ligands facilitates the ability to dissolve the different precursors uniformly in a single solvent under similar conditions.
L addition, the multi-metallic molecular precursors can be utilized in an ALD process that introduce other precursors in separate pulses. This is not a preferred embodiment, as it fails to embrace the full benefit of the invention which permits the precursor introduction to be consolidated into a single step. Nonetheless, the use of multi-metallic molecular precursors in any ALD process will consolidate the number of pulses necessary and further the homogeneity of the resultant film. Accordingly, ALD processes that introduce other precursors in separate pulses are also embraced if they utilize a multi-metallic molecular precursor. Multi-Metallic Molecular Precursor Cocktails
In another aspect of the present invention, a second ALD method for forming a multi- metallic film on a substrate comprises at least one cycle that comprises the step of introducing a mixture of metallic molecular precursor gases into a deposition chamber that contains the substrate. In one embodiment, the second ALD method comprises at least one cycle that comprises the following steps: (i) introducing a mixture of at least two different metallic molecular precursors to a deposition chamber; (ii) purging the deposition chamber; (iii) introducing a reactant gas to the deposition chamber; and (iv) purging the deposition chamber. This embodiment of the method is visually illustrated by FIG. 3. In FIG. 3 is identical to FIG. 1A, with the exception that a vapor mixture of metallic precursors 310 is utilized instead of a multi-metallic molecular precursor vapor 110. Similarly, the steps in the second method are the same as those employed in the first method with the exception that a vapor mixture of metallic precursors 310 is utilized in the first step of the cycle rather than a multi-metallic molecular precursor 110.
Each metallic precursor contains, within its molecules, a metallic element required to make the desired film. In one embodiment, the metallic precursors in the mixture have the following formulae:
(I^wM1; and
M2(L2)Z
1 9 1 9 where M and M are different metallic elements, where each L and L a ligand and may be the same or different and where w and z are integers less than or equal to a valence number for M and M , respectively. As stated, M1 and M2 can be any metallic element as long as M1 and M2 are not identical. Preferred metallic elements for use as M1 and M2 include Si, Li, Be, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, TI, Pb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th. As stated, each L1 and L2 is selected, independently, from ligands and may be the same or different. Suitable ligands are readily ascertainable by those of ordinary skill in the art and include those ligands known to be useful in precursors for ALD processes. Undesirable ligands are removed during the course of film deposition due to their relatively weak chemical bonds. Preferred ligands include but are not limited to a double bonded nitrogen, alkyls, alkoxides, halides, hydrides, amides, imides, azides, nitrates, cyclopentadienyls, carbonyls, carboxylates, diketonates, as well as substituted analogs thereof and combinations thereof. It is preferable, but not necessary to use relatively small ligands having, e.g., 1-12 atoms. Compounds that contain small relatively small ligands tend to volatilize more readily at lower temperatures than compounds that contain relatively larger ligands. Furthermore, compounds that contain relatively smaller ligands tend to be more stable. Specific preferred ligands include a double bonded nitrogen (=N), dimethylamide (- N(CH3)2), diethylamide (-N(CH2CH3)2), methylethylamide (-N(CH3)(CH2CH3)), methoxide (-OCH3), ethoxide (-OCH2CH3), and butoxide (-O(CH2)3CH3). It is also preferably, but not necessary to use similar, and more preferably identical, ligands in both precursors. The use of identical ligands facilitates the ability to dissolve the different precursors uniformly in the same solvent under the similar conditions.
As stated, w and z are integers less than or equal to a valence number for M1 and M2, respectively. In one embodiment, either at least one of w and z is an integer one less than a valence number for metallic element due to the presence of a double bond between one of the ligands and the metallic element. In another embodiment, w and z are integers equal to a valence number for their respective metallic elements. Preferably, w and z are selected, independently, from 1, 2, 3 and 4.
The precursor vapors 310 can be mixed in the deposition zone, or a mixture of precursor gases 310 can be delivered to the deposition zone by direct liquid injection (DLI) of a mixture of precursors in liquid phase. When delivering by direct liquid injection, the liquid precursors are vaporized in a separate vaporization step. In one embodiment the vapor of the individual precursors is mixed in the delivery manifold and deposition chamber 101 during the precursor pulse step, h another embodiment an alternating precursor pulse sequence is used.
The diluent gas 120 can be any non-reactive gas or mixture of non-reactive gases, including any noble gas or gases. Typical non-reactive gases include Ar, He, Ne, Xe, and N2.
The reactant gas 130 can be any reducing agent or oxidizing agent or a mixture thereof. Thus, in FIG. IB, the reactant gas 130 is reducing agent 130' and in FIG. IC the reactant gas 130 is oxidizing agent 130". The reducing agent 130' or oxidizing agent 130" may be a gas or a liquid at room temperature but it is introduced to the deposition chamber 101 as a gas. The nature of the reactant gas 130 is selected based on the nature of the multi- metallic film desired. Suitable reactant gases 130 include hydrogen sources, oxygen sources and or nitrogen sources.
In one embodiment, the mixture of precursors is a mixture of the two compounds M(NR8R9)q and Si(NRI0Rn)2 where R8, R9, R10 and R11 are, independently, selected from H, F, C1-C6 alkyls, and substituted C1-C6 alkyls, where M is selected from Si, Li, Be, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, TI, Pb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th, and q is less than or equal to a valence number for M. Preferred selections for R8, R9, R10 and Rπ are methyl and ethyl. Preferred selections for M are Ti, Zr, and Hf and, in such cases, q equals 2, 3 or 4.
In one such embodiment, the precursor cocktail is a mixture of N=Ta(NR'R")3 and Si(NRR')4. This cocktail is especially useful for depositing a tantalum silicon nitride layer.
In another such embodiment the precursor cocktail is a mixture of Hf(NR12R13)4 and Si(NR14RI5)4, where R12, R13, R14 and R15 are selected from methyl and ethyl groups. This mixture can be used to deposit a number of different halfnium-silicon films depending on the nature of the reactant utilized. For example, if the reactant is an oxygen source, then the multi-component film will be a hafnium silicate (Hf-Si-O) film. Alternatively, if the reactant is a nitrogen source, a hafnium silicon nitride (Hf-Si-N) film will be formed. Alternatively, if a mixture of oxygen and nitrogen sources is utilized, the resultant film will be a hafnium oxynitride (Hf-Si-O-N) film. Finally, if a hydrogen source is utilized, a hafnium silicon alloy (Hf-Si) film will be formed. Suitable oxygen sources, nitrogen sources, and hydrogen sources are identical to those identified previously.
When depositing HfSiO films from a precursor cocktail comprising Hf(NR12R13)4 and Si(NR14RI5)4 using ALD, the mixture can range anywhere from 10:1 to 1: 10 by volume and the vapor flow rate can range anywhere from approximately 0.01 g/min to 10 g/min. When the oxidizer is ozone, which is preferred, the total O2/O3 flow can range anywhere from approximately 100 seem to 1000 seem and the ozone concentration can range anywhere from 1% to 20% by volume. During the deposition, the process pressure can range anywhere from approximately 50 mTorr to 10 Torr and the substrate temperature can range anywhere from approximately 200 °C to 600 °C, with the preferred substrate temperature being from approximately 300 °C to 400 °C. The dilution gas flow rate can range anywhere from approximately 100 seem to 2000 seem, but preferably ranges from approximately 500 seem to 2000 seem.
A specific example of a mixture of precursors for deposition of HfSiO films using a cocktail comprising Hf(NR12R13)4 and Si(NR14R15)4 is the case where R12 and R14 are methyl and R13 and R15 are ethyl. The resulting hafnium and silicon precursors are tetrakis(ethylmethylamino) hafnium (i.e., TEMAHf) and tetrakis(ethylmethylamino) silicon (i.e., TEMASi). In this example, a solventless precursor mixture of TEMAHf and TEMASi was delivered to the deposition region using a direct liquid injection system equipped with a vaporizer. Ozone was used as an oxygen source for depositing the metal oxide films. Various precursor mixtures were used, ranging from a 99:1 HfiSi molar ratio mixture to a 1:99 HfiSi molar ratio mixture, hi this example, the liquid flow rate can range from approximately 0.01 to 1 g/min, but the flow rate is preferably in the range approximately 0.02 to 0.1 g/min. The oxygen flow can range from approximately 100 seem to 1000 seem. The deposition temperature can range from approximately 250 °C to 450 °C. Using a flow rate of 0.04 g/min and an oxygen flow of 300 seem with 12% by volume O3 at temperatures from 300 °C to 450 °C it is possible to obtain HfSiO films with varying composition (see Table 1 below).
Table 1 Rutherford Back Scattering Spectroscopy/Hydrogen Forward Scattering (RBS/HFS) composition analysis of Hf-Si-O films
Water
Temperature Rl @ 633nm (°C) O Si Hf 0/(Hf+Si) H C N for 500A films
300 61.9 6.9 23.5 2.04 3.5 3.3 0.9 1.83
350 63.4 10.9 20.3 2.03 1.4 3 1 1.77
400 62.7 13.3 18.5 1.97 1.8 2.5 1.2 1.72
450 63.8 13.7 18.8 1.96 1 2.1 0.6 1.68 A transmission electron microscope cross section image of 45A Hfo.58Si0. 2O2 is shown in FIG. 4 for the HfSiO film deposited at 400°C. A polysilicon cap layer was also deposited followed by a thermal anneal at 700°C for 30 s. The amorphous state of the film was maintained after the anneal with an interfacial oxide layer thickness of approximately 7A.
ALD depositions embraced by these methods include thermal ALD, photo-assisted ALD, laser assisted ALD, plasma-assisted ALD and radical assisted ALD.
The preceding description is illustrative rather than limiting and is intended to provide a written description of the inventions sufficient to enable one of ordinary skill in the art to practice the full scope and any best mode of the inventions to which patent rights are claimed. Other embodiments and modifications may be readily apparent to those skilled in the art. All such embodiments and modifications should be considered part of the inventions if they fall within the scope of the appended claims and any equivalents thereto.

Claims

What is claimed:
1. An atomic layer deposition method for depositing a multi-metallic film on a substrate, characterized in that at least one cycle is performed that comprises the step of introducing a multi-metallic molecular precursor gas into a deposition chamber that contains the substrate.
2. A method of forming a multi-metallic film on a substrate comprising at least one cycle that comprises the following steps:
(i) introducing a multi-metallic molecular precursor gas into a deposition chamber that contains the substrate;
(ii) purging the deposition chamber;
(iii) introducing one or more reactant gases into the deposition chamber; and
(iv) purging the deposition chamber.
3. The method of claim 2 where the multi-metallic molecular precursor has the following formula:
O MWO , where M1 and M2 are different metallic elements, where each L1 and L2 is a leaving group that may be the same or different, where a and b may be the same or different and are integers less than a valence number for M1 and M2, respectively, and where G is selected from a single bond, double bond, bridging atom and bridging group.
4. The method of claim 3 where G is oxygen.
-
5. The method of claim 3 where M and M are different metallic elements selected from
Si, Li, Be, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, TI, Pb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th..
6. The method of claim 3 where each L and L is a leaving group selected from alkyls, alkoxides, halides, hydrides, amides, imides, azides, nitrates, cyclopentadienyls, carbonyls, carboxylates, diketonates, and substituted analogs thereof.
7. The method of claim 6 where each L1 and L2 is a leaving group selected from dimethylamide, diethylamide, methylethylamide, methoxide, ethoxide and butoxide.
8. The method of claim 3 where a and b are selected, independently, from the integers 1, 2 and 3.
9. The method of claim 3 where the multi-metallic molecular precursor has the following formula:
(R1O)x(R2R3N)3-xSi-O-M(OR4)y(NR5R6)v-y, where R1, R2, R3, R4, R5 and R6 are, independently, selected from H, F, C1-C6 alkyls and substituted C1-C6 alkyls, where M is selected from Si, Li, Be, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, hi, Sn, Sb, Te, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, TI, Pb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th, where x is selected from 1, 2 and 3, where y is an integer less than or equal to v and where v is an integer one less than a valance number for M.
10. The method of claim 9 where the M is selected from Ti, Zr and Hf.
11. The method of claim 10 where the multi-metallic molecular precursor is tri-(tert- butoxy)siloxy-tri(tert-butoxy)titanium.
12. The method of claim 9 wherein R2, R3, R5 and R6 are selected from methyl and ethyl, where R1 and R are selected from methyl, ethyl, propyl, and butyl, where M is selected from Ti, Zr, and Hf and where v is selected from the integers 1, 2 and 3.
13. The method of any one of claim 2, 3, and 4 where the reactant gas is an oxidizing agent.
14. The method of any one of claims 2, 3 and 4 where the reactant gas is a reducing agent.
15. The method of any one of claim 2, 3 and 4 where the reactant gas is a hydrogen source and the multi-metallic film is a metallic alloy film.
16. The method of any one of claims 2, 3 and 4 where the reactant gas is an oxygen source and the multi-metallic film is multi-metallic oxide film.
17. The method of any one of claims 2, 3 and 4 where the reactant is a nitrogen source and the multi-metallic film is a multi-metallic nitride film.
18. The method of any one of claims 2, 3 and 4 where the reactant gas is a mixture of an oxygen source and a nitrogen source and the multi-metallic film is a multi-metallic oxynitride film.
19. The method of any one of claims 2, 3 and 4 where the purging steps are accomplished by pulsing diluent gas into the reaction chamber, or pumping gas out of the reaction chamber, or a combination of pulsing diluent gas into the reaction chamber and pumping gas out of the reaction chamber.
20. An atomic layer deposition method for forming a multi-metallic film on a substrate characterized in that at least one cycle is performed that comprises the step of introducing a mixture of metallic molecular precursor gases into a deposition chamber that contains the substrate.
21. A method of forming a multi-metallic film on a substrate comprising at least one cycle comprising the following steps:
(i) introducing a mixture of at least two different metallic molecular precursors into a deposition chamber that contains the substrate; (ii) purging the deposition chamber; (iii) introducing a reactant gas to the deposition chamber; and (iv) purging the deposition chamber.
22. The method of claim 21 where the two metallic molecular precursors comprise the following respective formulae:
( ^wM1; and M2(L2)Z
1 9 1 where M and M are different metallic elements, where each L and L are ligands which may be the same or different, where w and z are integers less than or equal to a valence numbers for M1 and M2, respectively.
23. The method of claim 22 where M1 and M2 are different metallic elements selected from Si, Li, Be, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Ba, La, Hf, Ta, W, Re, Os, Ir, Pt, Au, TI, Pb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th..
1
24. The method of claim 22 where each L and L is a leaving groups, which may be the same or different, selected from a double bonded nitrogen, alkyls, alkoxides, halides, hydrides, amides, imides, azides, nitrates, cyclopentadienyls, carbonyls, carboxylates, diketonates, and substituted analogs thereof.
25. The method of claim 22 where each L 1 and L 9 is a leaving group selected from a double bonded nitrogen, dimethylamide, diethylamide, methylethylamide, methoxide, ethoxide and butoxide.
26. The method of claim 22 where each L 1 and L 9 is the same.
27. The method of claim 22 where w and z are selected, independently, from 1, 2, 3 and 4.
28. The method of claim 22 where the two metallic precursors comprise the following respective formulae:
M(NR8R9)q; and Si(NR10Rπ)2 where R8, R9, R10 and R11 are, independently, selected from H, F, C1-C6 alkyls, and substituted C1-C6 alkyls, where M is selected from Si, Li, Be, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, Ba, La, Hf, Ta, W, Re, Os, hr, Pt, Au, TI, Pb, Bi, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Th, and where q is less than or equal to a valence number for M.
29. The method of claim 28 where M is selected from Ti, Zr and Hf.
30. The method of claim 28 where the two metallic precursors are N=Ta(NR'R") and Si(NRR')4.
31. The method of claim 28 wherein the two metallic precursors are tetrakis(ethylmethylamino) hafnium and tetrakis(ethylmethylamino) silicon.
32. The method of any one of claims 21 and 22 where the reactant gas is an oxidizing agent.
33. The method of any one of claims 21 and 22 where the reactant gas is a reducing agent.
34. The method of any one of claims 21 and 22 where the reactant gas is a hydrogen source and the multi-metallic film is a metallic alloy film.
35. The method of any one of claims 21 and 22 where the reactant gas is an oxygen source and the multi-metallic film is multi-metallic oxide film.
36. The method of any one of claims 21 and 22 where the reactant has is a nitrogen source and the multi-metallic film is a multi-metallic nitride film.
37. The method of any one of claims 21 and 22 where the reactant gas is a mixture of an
^ oxygen source and a nitrogen source and the multi-metallic film is a multi-metallic oxynitride film.
38. The method of any one of claims 21 and 22 where the purging steps are accomplished by pulsing diluent gas into the reaction chamber, or pumping gas out of the reaction chamber, or a combination of pulsing diluent gas into the reaction chamber and pumping gas out of the reaction chamber.
39. The method of any one of claims 1 and 20 where said method for atomic layer deposition is a method selected from thermal atomic layer deposition, photo-assisted atomic layer deposition, laser assisted atomic layer deposition, plasma assisted atomic layer deposition and radical enhanced atomic layer deposition.
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