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Patent

  1. Avancerad patentsökning
PublikationsnummerUS20050233156 A1
Typ av kungörelseAnsökan
AnsökningsnummerUS 11/166,258
Publiceringsdatum20 okt 2005
Registreringsdatum24 jun 2005
Prioritetsdatum21 apr 2003
Även publicerat somEP1616042A2, US7470470, US20050064207, WO2004105083A2, WO2004105083A3
Publikationsnummer11166258, 166258, US 2005/0233156 A1, US 2005/233156 A1, US 20050233156 A1, US 20050233156A1, US 2005233156 A1, US 2005233156A1, US-A1-20050233156, US-A1-2005233156, US2005/0233156A1, US2005/233156A1, US20050233156 A1, US20050233156A1, US2005233156 A1, US2005233156A1
UppfinnareYoshihide Senzaki, Seung Park
Ursprunglig innehavareAviza Technology, Inc.
Exportera citatBiBTeX, EndNote, RefMan
Externa länkar: USPTO, Överlåtelse av äganderätt till patent som har registrerats av USPTO, Espacenet
System and method for forming multi-component dielectric films
US 20050233156 A1
Sammanfattning
The present invention provides systems and methods for mixing precursors such that a mixture of precursors are present together in a chamber during a single pulse step in an atomic layer deposition (ALD) process to form a multi-component film. The precursors are comprised of at least one different chemical component, and such different components will form a mono-layer to produce a multi-component film. In a further aspect of the present invention, a dielectric film having a composition gradient is provided.
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Anspråk(21)
1. A method of forming a film on a surface of a substrate, characterized in that:
two or more precursors, each of the precursors containing at least one different chemical component, are conveyed to a process chamber together and form a mono-layer on the surface of the substrate, said mono-layer containing each of the separate chemical components, said process chamber being configured to house a plurality of substrates.
2. The method of claim 1 wherein said substrate surface is selected from the group consisting of silicon, plastics, polymers, metals, alloys, organics, inorganics, or mixtures thereof.
3. The method of claim 1 where the precursors have the formula:

M(L)x
where M is a metal selected from the group of: Ti, Zr, Hf, Ta, W, Mo, Ni, Si, Cr, Y, La, C, Nb, Zn, Fe, Cu, Al, Sn, Ce, Pr, Sm, Eu, Th, Dy, Ho, Er, Tm, Yb, Lu, Ga, In, Ru, Mn, Sr, Ba, Ca, V, Co, Os, Rh, Ir, Pd, Pt, Bi, Sn, Pb, Tl, Ge or mixtures thereof; where L is a ligand selected from the group consisting of amine, amides, alkoxides, halogens, hydrides, alkyls, asides, nitrates, nitrites, cyclopentadienyls, carbonyl, carboxylates, diketonates, alkenes, alkynes, or a substituted analogs thereof, and combinations thereof; and where x is an integer less than or equal to the valence number for M.
4. The method of claim 1 further comprising supplying at least one reactant that reacts with said monolayer.
5. The method of claim 4, wherein said at least one reactant is delivered sequentially or simultaneously with the precursors.
6. The method of claim 4, wherein said at least one reactant is a nitridating reactant, reducing reactant, oxidizing reactant, or a mixture thereof.
7. The method of claim 6, wherein said nitridating reactant is selected from the group consisting of ammonia, deuterated ammonia, 15N-ammonia, amines or amides, hydrazines, alkyl hydrazines, nitrogen gas, nitric oxide, nitrous oxide, nitrogen radicals, N-oxides, or mixtures thereof.
8. The method of claim 6, wherein said oxidizing reactant is selected from the group consisting of ozone, oxygen, singlet oxygen, triplet oxygen, atomic oxygen, water, peroxides, air, nitrous oxide, nitric oxide, H2O2, and mixtures thereof.
9. A method for forming a multi-component film on a surface of a substrate comprising the steps of:
vaporizing two or more precursors, each of the precursors containing at least one metal or metalloid component;
conveying the two or more precursors into a process chamber configured to house a plurality of substrates, wherein the precursors are present together in the process chamber;
forming a mono-layer on the surface of the substrate, said mono-layer containing each of the metal or metalloid components; and
purging said process chamber.
10. The method of claim 9 wherein said forming step is carried out at a temperature in the range of approximately 20 to 800 C.
11. The method of claim 9 wherein said process chamber is at a pressure in the range of approximately 0.001 mTorr to 600 Torr.
12. The method of claim 9 wherein the step of conveying further includes mixing the two or more precursors and conveying the mixture of precursors into the process chamber.
13. The method of claim 9, wherein said purging step further comprises introducing a carrier gas to evacuate the precursors from the chamber.
14. The method of claim 9 further comprising conveying a reactant gas to the process chamber, wherein the reactant gas contacts the mono-layer formed on the surface of the substrate.
15. The method of claim 14 wherein the gas flow rate to the process chamber is in the range of approximately 0 to 20,000 sccm.
16. The method of claim 9 where the precursors have the formula:

M(L)x
where M is a metal selected from the group of: Ti, Zr, Hf, Ta, W, Mo, Ni, Si, Cr, Y, La, C, Nb, Zn, Fe, Cu, Al, Sn, Ce, Pr, Sm, Eu, Th, Dy, Ho, Er, Tm, Yb, Lu, Ga, In, Ru, Mn, Sr, Ba, Ca, V, Co, Os, Rh, Ir, Pd, Pt, Bi, Sn, Pb, Tl, Ge or mixtures thereof; where L is a ligand selected from the group consisting of amine, amides, alkoxides, halogens, hydrides, alkyls, asides, nitrates, nitrites, cyclopentadienyls, carbonyl, carboxylates, diketonates, alkenes, alkynes, or a substituted analogs thereof, and combinations thereof; and where x is an integer less than or equal to the valence number for M.
17. A system for atomic layer deposition comprising:
at least a first vaporizer containing a first deposition precursor for deposition;
a least a second vaporizer containing a second deposition precursor for deposition;
a process chamber configured to house a plurality of substrates and adapted to carry out an atomic layer deposition process; and
a manifold, said manifold being coupled to said first and second vaporizers and to said process chamber, said manifold being adapted to mix and convey the first and second deposition precursors to said process chamber.
18. The system of claim 17, wherein said process chamber further comprises:
a gas inlet coupled to said manifold; and
an inlet for supplying at least one reactant gas, wherein said inlet provides said at least one reactant in said process chamber in-situ in either sequential or simultaneous manner.
19. The method of claim 1 wherein said monolayer is selected from the group consisting of metals and metal, metal alloy or mix metal oxides, silicates, nitrides and oxynitrides.
20. The method of claim 1 wherein each said monolayer is compositionally variable and electrically and physically compatible with the adjacent said monolayers.
21. A method of forming a film on the surface of a substrate, characterized in that:
two or more precursors, each of the precursors containing at least one different chemical component, are conveyed to a process chamber together and form a mono-layer on the surface of the substrate, said process chamber being configured to house a plurality of substrates and wherein the amount of each of the precursors conveyed to the process chamber is selectively controlled such that a desired composition gradient of one of more of the chemical components is formed in the film.
Beskrivning
    CROSS REFERENCE TO RELATED APPLICATIONS
  • [0001]
    This application is a Continuation Application of U.S. patent application Ser. No. 10/829,781 filed Apr. 21, 2004, entitled “System and Method for Forming Multi-Component Dielectric Films” which claims the benefit of, and priority to, each of U.S. provisional patent application Ser. No. 60/464,458 filed on Apr. 21, 2003 entitled Fabrication Method of Multi-Component Films; U.S. provisional patent application Ser. No. 60/520,964 filed Nov. 17, 2003 entitled ALD of HfSiON with Controlled Thickness and Composition Gradient; and U.S. provisional patent application Ser. No. 60/560,952 filed Apr. 9, 2004 entitled Atomic Layer Deposition of Metal or Mixed Metal Thin Films, the entire disclosures of each of which are incorporated by reference herein.
  • FIELD OF THE INVENTION
  • [0002]
    In general, the present invention relates to systems and methods for forming dielectric films in semiconductor applications. More specifically, the present invention relates to systems and methods for fabricating multi-component dielectric films on a substrate using mixed vaporized precursors.
  • BACKGROUND OF THE INVENTION
  • [0003]
    Concurrent with the increase in sophistication and drive towards miniaturization of microelectronics, the number of transistors per integrated circuit has exponentially grown and promises to grow to meet the demands for faster, smaller and more powerful electronic systems. However, as traditional silicon-based transistor geometries reach a critical point where the silicon dioxide gate dielectric becomes just a few atomic layers thick, tunneling of electrons will become more prevalent leading to current leakage and increase in power dissipation. Accordingly, an alternative dielectric possessing a higher permittivity or dielectric constant than silicon dioxide and capable of preventing current tunneling or leakage would be highly desirable. Among the most promising dielectric candidates to replace silicon dioxide includes hafnium oxide, zirconium oxide and tantalum oxide.
  • [0004]
    Unfortunately, these materials are chemically and thermally unstable on silicon, unlike silicon dioxide, forming defects and charge traps at the interface between the metal dielectric and the silicon substrate. The charge traps and defects absorb the voltage applied at the gate and perturb the performance and reliability of the transistor. To limit the formation of interfacial charge traps and defects, an interfacial layer of silicon dioxide is deposited in between the dielectric and the silicon substrate. The silicon dioxide interface buffers the silicon substrate from the dielectric, but the silicon dioxide interface may not be compatible with the surface properties of the dielectric. Accordingly, an interface that can ameliorate the surface properties and chemistries of the dielectric and silicon substrate, while minimizing the equivalent physical oxide thickness, is needed to fabricate ultra-thin high k dielectrics.
  • [0005]
    Prior art deposition techniques for fabricating films such as chemical vapor deposition (CVD) are increasingly unable to meet the requirements of advanced thin films. While CVD processes can be tailored to provide conformal films with improved step coverage, CVD processes often require high processing temperatures. For instance, one of the obstacles of making high k gate dielectrics is the formation of an interfacial silicon oxide layer during CVD processes. Gas phase reaction in CVD leads to particle generation. Another obstacle is the limitation of prior art CVD processes in depositing ultra thin films for high k gate dielectrics on a silicon substrate.
  • [0006]
    An alternative to traditional CVD processes to deposit very thin films is Atomic layer deposition (ALD). ALD has several advantages over traditional CVD. ALD can be performed at comparatively low temperatures which is compatible with the industry's trend toward lower temperatures, and can produce conformal thin film layers. he existing method for depositing multi-component films, such as a HfxSiyO2(x+y=1) film, using an ALD processes is to deposit laminate films of HfO2 and SiO2 film using a sequential vapor deposition method. That is, the precursor chemicals are not mixed, and instead an Hf containing precursor and a Si containing precursor are pulsed independently and sequentially into the chamber to form laminate layers of HfO and SiO2, respectively. In fact, any mixing of precursors is prohibited, and the chamber is purged of one precursor before the second precursor is pulsed. Once the laminate films are formed to a desired thickness, the film is annealed in an attempt to arrive at more continuous composition throughout the film. This approach of building up layers of different laminate films leads to many electron traps in the film due to the multiple interfaces which requires high temperature thermal anneal to fix the traps. The addition of the high temperature thermal annealing step increases cost and time for manufacturing semiconductors, and moreover can result in the undesirable out migration of elements from previously formed layers on the wafer. In addition, it is difficult to control the stoichiometric composition of multi-component films in the laminate method. The dielectric constant (k), crystallization temperature and refractive index of HfSiOx films cannot be easily controlled by the traditional one chemical sequential precursor pulse methods (such as the laminate method). Furthermore, the cycle times needed to form a film of desired thickness using the conventional sequential pulse and purge of one chemical precursor at a time are impractical and require too much time for future IC manufacturing.
  • [0007]
    Attempts to fabricate a multi-component films using mixed precursors have been limited to the traditional CVD methods. For example, U.S. Pat. Nos. 6,537,613 and 6,238,734 both to Senzaki et al. (the '613 and '734 patents) generally disclose system and methods for generating a compositional gradient comprising a metal and metalloid compound by direct liquid injection. In direct liquid injection (DLI), the metal and metalloid precursors are mixed together to form a solventless liquid mixture prior to injection of the mixture into the deposition system.
  • [0008]
    There are however several drawbacks associated with the method described in the '613 and '734 patents. Specifically, it is a liquid mixture that is injected. As such, if the liquid mixture is not thoroughly mixed, a film having an uneven composition and gradient will form on the substrate. In addition, even if appropriate volumes of samples are provided, there is no guarantee that the mixture will vaporize uniformly since each precursor has a unique boiling point, vapor pressure and volatility. Furthermore, if the discrepancy in boiling points between the precursors is substantial, one precursor may decompose at the boiling point of the second forming particulates or contaminants. Generally, either the precursors have not been adequately mixed, resulting in a non-uniform film composition, or mixing of the two vapors causes pre-reaction in the gas phase, resulting in the formation of particles or contaminants that are deposited on the wafer.
  • [0009]
    Accordingly, there is a need for further developments in methods of fabricating multi-component films. There is particularly a need for a method of fabricating multi-component films using an ALD process. It is further desirable that the method provides control of the stoichiometric composition or gradient of a multi-component film.
  • BRIEF SUMMARY OF THE INVENTION
  • [0010]
    In general, the inventors have discovered a method that provides for mixing vaporized precursors such that a mixture of vaporized precursors are present together in a chamber during a single deposition or pulse step in an atomic layer deposition (ALD) process to form a multi-component film. The vaporized precursors are each comprised of at least one different chemical component, and such different components will form a mono-layer to produce a multi-component film. The inventors refer to this method as “co-injection ALD.” Such a method is a departure from the prior art, where the vaporized precursors are pulsed separately into the chamber in the ALD process to form separate mono-layers containing only one of the components.
  • [0011]
    One aspect of the present invention provides systems and methods for fabricating multi-component dielectric films by mixing vaporized precursors together and then injecting or co-injecting the vaporized precursors such that a mixture of precursors are present in the ALD chamber. As used herein the term “muti-component” film means that the film contains two or more metal or metalloid elements. A variety of multi-component films may be formed by the present invention, including but not limited to: metal, metal alloy, mixed metal oxides, silicates, nitrides, oxynitrides, and mixtures thereof.
  • [0012]
    In one embodiment of the present invention, a method of forming a thin film on a surface of a substrate by atomic layer deposition is provided, characterized in that: two or more vaporized precursors each of the precursors containing at least one different chemical component (typically a metal or metalloid element), are conveyed into a process chamber together to form a mono-layer on the surface of the substrate, and said mono-layer contains each of the separate chemical components. In general the term co-injecting is used to mean that two or more precursors having at least one different chemical component are present in a chamber such that a film is produced having multiple components. This may be accomplished by injecting or conveying precursors together in either vapor or liquid state (aerosol) into a process chamber, or mixing the precursors in the process chamber. Mixing of the precursors prior to introduction into the process chamber is preferred, but not required.
  • [0013]
    In another aspect the present invention provides a system for forming multi-component films. In one embodiment, the system generally includes one or more vaporizers, each vaporizer being coupled to a manifold. The manifold is configured to mix the vaporized precursors generated by the vaporizers. The manifold is coupled to an inlet to a process chamber and the mixed precursors are injected into the chamber through the inlet. In one embodiment the inlet is comprised of an injector, such as a showerhead injector. It is possible that the precursors may be mixed in the injector, and not in a manifold.
  • [0014]
    In yet another aspect of the present invention, a system and method is provided for forming a multi-component film having a compositional gradient. In one embodiment a method of forming a multi-component film is provided characterized in that two or more vaporized precursors each of the precursors containing at least one different chemical component, are injected into a process chamber together to form a mono-layer on the surface of the substrate, wherein the gas flow rate of each of the vaporized precursors injected into the chamber are selectively controlled such that a desired composition gradient of one or more of the different chemical components is formed in the film.
  • [0015]
    In a further aspect of the present invention, a dielectric film having a composition gradient is provided comprising: a silicon-rich bottom layer, a nitrogen-rich top layer, and at least one hafnium-rich layer between said top and bottom layers. In one embodiment nitrogen is deposited selectively near or above a silicon substrate-dielectric interface to deter boron diffusion. In further embodiments, it is desirable to provide system and methods for deterring boron diffusion without placing a burden on the equivalent physical oxide thickness of the dielectric and quality of the interface between the silicon and the nitride dielectric, leading, for example, to higher trap densities. In one embodiment, a compositional gradient may be used to “buffer” the dielectric and the substrate. For example, when the substrate is silicon, a first layer is deposited rich in silicon and lesser amounts of a second deposition metal that makes up the dielectric. Atop the first layer, a second layer comprising predominantly a deposition metal that makes up the dielectric is deposited in addition to substantial lesser amounts of silicon. In some embodiments, additional layers can be added to blend the surface properties and chemistries of the adjacent layers. In various embodiments, each layer can be oxidized, reduced, nitridated, or a combination thereof in-situ.
  • [0016]
    Further, the invention provides systems and methods for fabricating multi-component oxynitride films, wherein a multi-component film is formed by the method described above, and then the film is oxidized at elevated temperatures with an oxidizing reactant selected from the group consisting of ozone, oxygen, peroxides, water, air, nitrous oxide, nitric oxide, N-oxides, or mixtures thereof. Of particular advantage, the oxidation step can be preformed in-situ. Following oxidation, an excited nitrogen source is sequentially conveyed to the process chamber and permitted to react with the oxidized layer at elevated temperatures to form an oxynitride. Again, this step is performed in-situ.
  • [0017]
    In a preferred embodiment, the invention provides systems and methods for fabricating multi-component oxynitride films by mixing precursors that contain a nitridating reactant into the chamber and carrying our the ALD process at relatively low temperatures. Suitable nitridating agents can be selected from the group consisting of ammonia, deuterated ammonia, 15N-ammonia, amines or amides, hydrazines, alkyl hydrazines, nitrogen gas, nitric oxide, nitrous oxide, nitrogen radicals, N-oxides, or mixtures thereof.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0018]
    Other aspects, embodiments and advantages of the invention will become apparent upon reading of the detailed description of the invention and the appended claims provided below, and upon reference to the drawings in which:
  • [0019]
    FIG. 1 is a schematic block diagram of an system for fabricating a multi-component, multi-layered film in accordance with one embodiment of the present invention.
  • [0020]
    FIG. 2 is a cross-section al view of a high k dielectric gate material formed utilizing system and methods of the present invention.
  • [0021]
    FIG. 3 is a flow chart illustrating the method for fabrication of the compositional gradient films according to one embodiment of the present invention.
  • [0022]
    FIG. 4 illustrates the relationship between film composition and the deposition precursor gas flow rates. In this particular example, the deposition and composition of hafnium-silicon films can be modified by controlling the hafnium and silicon deposition gas flow rates.
  • [0023]
    FIG. 5 tabulates the results of the atomic compositional analysis of various HfSiO films fabricated by the system and method of the present invention. The results indicate that over a given hafnium and silicon content concentration, the ratio of oxygen atoms to hafnium and silicon atoms is approximately 2. These results indicate that the HfSiO films fabricated by system and methods of the present invention, over a particular range, affords films having the structural formula HfxSi1-xO2. The percentage of carbon, hydrogen and nitrogen is only found in trace amounts.
  • [0024]
    FIGS. 6 a and 6 b show X-Ray Photoelectron Spectroscopy (XPS) spectra of a film having the formula Hf0.5Si0.5O2 generated by the system and method of the present invention. In particular, FIG. 6 a highlights the XPS spectrum of the 4f region of hafnium found in the film. FIG. 6 b highlights the XPS spectrum of the 2p region of silicon found in the film. In both spectra, very little or no impurities can be seen.
  • [0025]
    FIG. 7 depicts the index of refraction for various 50 nm thick HfxSi1-xO2 films on silicon wafers measured as a function of the Hf/(Hf+Si) ratios. The graph compares the index of refraction for as-deposited and post-deposition annealed films.
  • [0026]
    FIG. 8 illustrates the change in deposition rates for HfxSi1-xO2 films, resulting from the oxidation of hafnium-silicon films with ozone, with respect to the deposition temperature.
  • [0027]
    FIGS. 9 a-9 c shows various TEM cross-sectional images of Hf0.58Si0.42O2 films deposited at 400° C. on HF last treated silicon substrates. FIGS. 9 a, 9 b and 9 c show the TEM images of Hf0.58Si0.42O2 films having a dielectric thickness of 2.3 nm, 4.3 nm and 6.5 nm, respectively. In each case, the thickness of the interface measures approximately 1 nm.
  • [0028]
    FIG. 10 is cross-sectional TEM image of Hf0.58Si0.42O2 with polysilicon cap layer after an anneal at 700° C. in N2.
  • [0029]
    FIG. 11 measures the capacitance equivalent thickness (CET) and the leakage current density as a function of hafnium content for various HfxSi1-xO2 films on HF-last silicon wafers.
  • [0030]
    FIG. 12 measures the film tensile stress as a function of temperature for a 50 nm thick Hf0.34Si0.66O2 film.
  • [0031]
    FIG. 13 shows the X-ray Photoelectron Spectroscopy (XPS) spectra for nitrogen 1s and hafnium 4P3/2 regions for an HfSiO film nitridated with ammonia in a post-deposition annealing step. Relative to HfSiO, the XPS spectra of an HfSiON film at various take-off angles (TOA) reveal the presence of nitrogen in the film.
  • [0032]
    FIG. 14 is a graph of the deposition rate of HfO2, generated from the oxidation of hafnium dialkyl amide with ozone, as a function of deposition temperature.
  • [0033]
    FIG. 15 is a cross-sectional view of a thin film having a compositional gradient formed by the co-injection system and method of the present invention. FIG. 15 show thin films, fabricated sequentially and in-situ, comprising HfSiOx, HfO2 and HfOxNy or HfSiON layers.
  • [0034]
    FIGS. 16 a and 16 b illustrate reaction schemes that describes the two different ways to generate metal, metal alloy or mix metal oxynitrides of the present invention. FIG. 16 a shows a relatively high temperature process for generating oxynitrides, wherein the oxidation step precedes the nitridation step. Whereas, in FIG. 16 b, the oxidation step is reserved until the film has been nitridated under relatively low temperatures.
  • [0035]
    FIG. 17 shows the compositional profile below the surface of a typical oxynitride film. Nitrogen concentration is greatest on the surface of the film, and gradually decreases below the surface until the HfO2 layer is reached. With further penetration into the film, the concentration of HfO2 decreases giving away to HfSiOx, until the interfacial layer of the silicon substrate is reached.
  • DETAILED DESCRIPTION OF THE INVENTION
  • [0036]
    In general, the inventors have discovered a method that provides for mixing precursors such that a mixture of precursors are present in a chamber during a single pulse step in an atomic layer deposition (ALD) process to form a mono-layer having multiple chemical compounds on the surface of a substrate. The precursors are comprised of different chemical components, and such components will form the multi-component film. The inventors refer to this method as “co-injection ALD.” Such a method is a departure from the prior art, where the vaporized precursors are conveyed or pulsed separately into the chamber in the ALD process. A variety of multi-component films may be formed by the present invention, including but not limited to: metal, metal alloy, mixed metal oxides, silicates, nitrides, oxynitrides, and mixtures thereof.
  • [0037]
    In one aspect the present invention provides a system and method for reproducibly and substantially uniformly controlling the stoichiometric composition of a multi-component film.
  • [0038]
    In a series of embodiments, the present invention provides a system and method for fabricating dielectrics possessing a higher permittivity or dielectric constant than silicon dioxide and capable of preventing current tunneling or leakage. In another aspect of the present invention provides a system and method for fabricating an interface that can ameliorate the surface properties and chemistries of the dielectric and silicon substrate, while minimizing the equivalent physical oxide thickness.
  • [0039]
    Accordingly, in some embodiments and aspects of the present invention, the present invention provides system and methods for depositing nitrogen selectively near or above the silicon substrate-dielectric interface to deter boron diffusion and increase the crystallization temperature of high-k layers. In further embodiments, it is desirable to provide system and methods for deterring boron diffusion without placing a burden on the equivalent physical oxide thickness of the dielectric and quality of the interface between the silicon and the nitride dielectric, leading, for example, to higher trap densities.
  • [0040]
    In typical embodiments of the present invention, it is desirable to provide a system and method for conducting low temperature nitridation of films; and in another aspect of the present invention, the present invention provides system and methods for delivering a nitrogen reactant sequentially, in-situ, eliminating the need for external plasmas sources and benefiting from less processing steps and time.
  • [0041]
    In another aspect the present invention provides a system for forming multi-component films. In one embodiment, the system generally includes one or more vaporizers, each vaporizer being coupled to a manifold. The manifold is coupled to an inlet to a reaction or deposition chamber, said inlet being comprised of an injector, such as a showerhead injector, and the like.
  • [0042]
    Each vaporizer holds a single deposition precursor comprising at least one deposition metal. Each vaporizer is connected to a mass flow controller and temperature control unit. The mass flow controller and temperature unit may be selectively controlled to moderate the concentration of deposition precursors present in the process chamber. In one embodiment, each mass flow controller moderates the flow of carrier gas through the system, and, in turn, the carrier gas dilutes and transports the deposition precursor into the manifold or process chamber.
  • [0043]
    In some series of embodiments, the vaporizer is a bubbler that vaporizes a single deposition precursor comprising at least one deposition metal. A pressurized gas including the carrier gas is bubbled into the deposition precursor. The flow rate of the pressurized gas may be selectively controlled to adjust the concentration of the deposition precursor present in the process chamber.
  • [0044]
    In one embodiment, a manifold facilitates mixing of the deposition precursors prior to delivery into the process chamber. In some embodiments, the manifold contains a T-junction cavity that accommodates and mixes the deposition precursors prior to delivery into the process chamber. The manifold may be heated to facilitate the flow of deposition precursors into the process chamber so as to prevent condensation in the manifold. Alternatively, mixing of the precursors may take place in the process chamber and the manifold may be eliminated.
  • [0045]
    The deposition precursor is delivered to the process chamber typically via a gas inlet and a monolayer of deposition precursor is chemi and/or physi absorbed on the surface or the substrate. The substrate can be silicon, metal, metal alloy, glass or polymeric, plastic, organic or inorganic work pieces. The gas inlet may take a variety of forms. In one example the gas inlet is comprised of an injection, such as a showerhead injector and the like. Alternatively, the deposition precursor is delivered to the substrate surface by a plurality of injectors.
  • [0046]
    Generally, the substrate is supported on a wafer support such as an electrostatic or vacuum chuck during deposition when a single wafer chamber is used. In one embodiment, the chuck is capable of cooling or heating the substrate by conduction, convection, radiative or non-radiative processes, or a mixture thereof. Alternatively, a the wafer support may be a boat or cassette which supports a plurality of substrates for batch processing.
  • [0047]
    An inlet port switchably provides oxidizing, reducing or nitridating reactants into the process chamber in-situ so as to promote sequential oxidation, reduction or nitridation of the monolayer or substrate surface.
  • [0048]
    In another aspect of the present invention, a dielectric film having a composition gradient is provided comprising: a silicon-rich bottom layer, a nitrogen-rich top layer, and at least one hafnium-rich layer between said top and bottom layers. In one embodiment nitrogen is deposited selectively near or above the silicon substrate-dielectric interface to deter boron diffusion. In further embodiments, it is desirable to provide a system and method for deterring boron diffusion without placing a burden on the equivalent physical oxide thickness of the dielectric and quality of the interface between the silicon and the nitride dielectric, leading, for example, to higher trap densities.
  • [0049]
    The invention further provides a system and method for fabricating multi-component oxynitride films, wherein the multi-component film is formed by the method described above, and then the film is oxidized at elevated temperatures with an oxidizing reactant selected from the group consisting of ozone, oxygen, peroxides, water, air, nitrous oxide, nitric oxide, H2O2, N-oxides, or mixtures thereof. Of particular advantage, the oxidation step can be preformed in-situ. Following oxidation, an excited nitrogen particle is sequentially conveyed to the process chamber and permitted to react with the oxidized layer at elevated temperatures to form an oxynitride. Again, this step is performed in-situ.
  • [0050]
    The invention provides a system and method for fabricating multi-component oxynitride films by mixing precursors that contain a nitridating reactant into the chamber and carrying our the ALD process at relatively low temperatures. Suitable nitridating agents can be selected from the group consisting of ammonia, deuterated ammonia, 15N-ammonia, amines or amides, hydrazines, alkyl hydrazines, nitrogen gas, nitric oxide, nitrous oxide, nitrogen radicals, N-oxides, atomic nitrogen or mixtures thereof.
  • [0051]
    Of particular advantage, he multi-component film of the invention is formed with a compositional gradient. A compositional gradient may be used to “buffer” the dielectric and the substrate. For example, when the substrate is silicon, a first layer is deposited rich in silicon and lesser amounts of a second deposition metal that makes up the dielectric. Atop the first layer, a second layer comprising predominantly a deposition metal that makes up the dielectric is deposited in addition to substantial lesser amounts of silicon. In some embodiments, additional layers can be added to blend the surface properties and chemistries of the adjacent layers. In various embodiments, each layer can be oxidized, reduced, nitridated, or a combination thereof in-situ. The composition gradient also provides refractive index gradient in the films, which provide unique optical properties of the films.
  • [0052]
    FIG. 1 is a simplified schematic diagram depicting a one embodiment of a system for fabricating a multi-component film in accordance with one embodiment of the present invention. Referring to FIG. 1, in general the system 100 comprises a process chamber 102 which houses wafer support 110 for supporting a wafer or substrate 112. A gas inlet 114 is provided for conveying deposition precursors and other gases 103 (for example, reactant gases such as oxidation gases and the like, or dilution gases) into the chamber 102 to form various layers or films on the surface of the substrate. In the illustrative embodiment, a gas manifold 104 interconnects one or more vaporizers 107, 109 to the process chamber 102. The illustrative embodiment shows two vaporizers however, any number of vaporizes may be employed. Each vaporizer comprises a reservoir 116, 118 for holding a deposition precursor or a mixture of deposition precursors 124, 126, respectively, and a vaporizer element 120, 122 through which a carrier gas is flowed to assist in vaporizing the contents in reservoirs 116,118. The flow of carrier gas into the vaporizers may be adjusted using a mass flow controller (not shown) to control the rate and concentration of the deposition precursors vaporized. Optionally, each vaporizer may be equipped with a heating element (not shown) to facilitate vaporization of the deposition precursors 124, 126 held in reservoirs 116, 118. Depending on the physical characteristics of the deposition precursors 124, 126, a combination of carrier gas and heating may be required to vaporize the deposition precursors in reservoirs 116, 118.
  • [0053]
    In one embodiment of the present invention, deposition precursors comprising at least one deposition metal are used having the formula:
    M(L)x
    where M is a metal selected from the group consisting of Ti, Zr, Hf, Ta, W, Mo, Ni, Si, Cr, Y, La, C, Nb, Zn, Fe, Cu, Al, Sn, Ce, Pr, Sm, Eu, Th, Dy, Ho, Er, Tm, Yb, Lu, Ga, In, Ru, Mn, Sr, Ba, Ca, V, Co, Os, Rh, Ir, Pd, Pt, Bi, Sn, Pb, Tl, Ge or mixtures thereof; where L is a ligand selected from the group consisting of amine, amides, alkoxides, halogens, hydrides, alkyls, azides, nitrates, nitrites, cyclopentadienyls, carbonyl, carboxylates, diketonates, alkenes, alkynes, or a substituted analogs thereof, and combinations thereof; and where x is an integer less than or equal to the valence number for M.
  • [0054]
    It is beneficial to select the ligands (L) to be the same in each of the deposition precursors to avoid ligand exchange from taking place when each of the precursors is mixed in vaporous form. Ligand exchange can lead to the formation of particulates that can adversely effect the quality of the deposited film. Ligands that do not undergo ligand exchange in vaporous form are also suitable.
  • [0055]
    In one preferred embodiment two deposition precursors are selected, a first deposition precursor where M is hafnium and a second deposition precursor where M is silicon. Both the first and second deposition precursor have the same ligands (L) to avoid ligand exchange from taking place when the first and second deposition precursor are mixed. Suitable ligands include, but not limited to, dimethylamine, diethylamine, diethyl methyl amine or tert-butoxide.
  • [0056]
    The hafnium source may comprise any one or combination of hafnium dialkyl amides, hafnium alkoxides, hafnium dieketonates, hafnium chloride (HfCl4), tetrakis(ethylmethylamino) hafnium (TEMA-Hf), and the like. The silicon source may comprise any one or combination of aminosilane, silicon alkoxides, silicon dialkyl amides, silane, silicon chlorides, tetramethyldisiloxane (TMDSO), tetrakis(ethylmethylamino) silicon (TEMA-Si), and the like. In one preferred embodiment, the liquid precursors 124, 126, are comprised of TEMA-Hf and TEMASi, respectively.
  • [0057]
    Deposition precursors are typically vaporized with a vaporizer. Each vaporizer holds a single deposition precursor. Each vaporizer is connected to a mass flow controller and a heating mechanism. As described above according to one embodiment of the present invention, a compositional gradient of one or more of the chemical components in the deposited film is provided. In one example, selective control of the composition is achieved by controlling the amount of precursor that is vaporized. The amount of precursor vaporized is generally controlled by adjusting the gas flow controller and/or the temperature unit which heats the vaporized in order to vaporize a desired concentration of the selected precursor(s). Additionally or alternatively, a dilution gas may be conveyed into the injector 114 or manifold 104 (not shown) and the flow rate of the dilution gas may be selectively controlled to dilute the amount of deposition precursor conveyed to the chamber 102.
  • [0058]
    The vaporizer may be comprised of a bubbler that vaporizes the deposition precursor comprising at least one deposition metal. When the vaporizer is a blubber, pressurized gas such as a carrier gas is bubbled into the deposition precursor reservoir 116, 118. Useful carrier gases include nitrogen, argon, or helium gas. The pressurized gas dilutes and carries the deposition precursors into their respective deposition precursor conduits 106, 108, and facilitates mixing of the deposition precursors. Optionally, to provide a compositional gradient in the film the concentration of one or more of the deposition precursors can be operable controlled by varying the temperature of the bubbler to selective increase or decrease the amount of deposition precursor vaporized. Temperature control can be conducted independently or in tandem with control of the mass flow controller and/or with the flow rate of the carrier gas. Thus, each of the various control mechanism can be used independently, or in a variety of combinations.
  • [0059]
    In other embodiments, due to the nature of the deposition precursors, the deposition precursors can be volatilized in reservoir 107, 109 by photolysis or enzymatic or chemical catalysis.
  • [0060]
    Referring again to FIG. 1, after the deposition precursors 124, 126 are vaporized, the deposition precursors 124, 126 are conveyed into manifold 104 through deposition precursor conduits 106, 108. The deposition precursor conduits 106, 108 can be of any shape, size, and length. The conduits 106, 108 can be fabricated from metal, plastics, polymers, or alloys. Typically, the conduits are made of the same material as the manifold 104. Similar to the manifold 104, the conduits 106, 108 can be insulated or heated to facilitate vaporization. Optionally, the conduits 106, 108 and the manifold 104 contain a sampling region for measuring the vapor concentration and composition spectroscopically or spectrometrically.
  • [0061]
    Mixing of the precursors can be facilitated by gravity or pressurized gas. Mixing can also be achieved by physical means such as a plunger to forcibly inject the precursors 124, 126 into manifold 104 through conduits 106, 108, where precursors 124, 126 are permitted to mix into a homogeneous deposition mixture. In some embodiments, the conduits 106, 108 converge and terminate at T-junction 130 in manifold 104, where precursors 124, 126 mix prior to delivery into process chamber 102.
  • [0062]
    Alternatively, conducts 106, 108 can converge and convey the respective precursors directly into a mixing region or cavity near or inlet to the chamber 102. In some embodiments, a filter can be inserted or attached to the manifold 104 to remove unwanted or isolate particular impurities and gases.
  • [0063]
    Optionally, referring back to the manifold 104 and conduits 106, 108, a heating or cooling element internally embedded or externally located can be used to regulate mixing and minimize particulate and impurity formation in the films.
  • [0064]
    The manifold 104 may take many forms suitable for mixing of the precursors prior to conveying the precursors to the chamber 102. The manifold 104 may be a single conduit coupled to the vaporizers via a junction, such as T-junction 130. The manifold 104 may include a cavity or reservoir to provide some residence time for the precursors to mix. In an alternative embodiment the manifold may be eliminated altogether, and the deposition precursors are conveyed directly to the gas inlet 114 and mixed in the gas inlet 114 (such as when the gas inlet is comprised of an injector) as they are conveyed into the chamber 102.
  • [0065]
    Still referring to FIG. 1, once the precursors 124, 126 have been vaporized, the deposition precursors 124, 126 are conveyed to the chamber 102 via one or more gases inlets 114. The gas inlet may take a variety of forms for delivery of gases to the chamber. In one embodiment, the gas inlet is comprised of an injector, such as a showerhead. It is also within the scope of the invention to incorporate a showerhead that utilizes a plurality of injectors adjustable in the process chamber 102 to provide desirable films. While the illustrative embodiment shows a single wafer chamber having one gas inlet 114, the present invention may be employed with a batch processing chamber, or with a mini-batch chamber. In a batch or mini-batch chamber, a plurality of gas inlets are employed and the gases are typically conveyed over each substrate in a parallel or cross-flow manner. Examples of a mini-batch chamber are described in PCT patent application serial no. PCT/US03/21575 entitled Thermal Processing System and Configurable Vertical Chamber, the disclosure of which is incorporated by reference herein.
  • [0066]
    A layer of the deposition mixture, comprising precursors 124, 126, is deposited on substrate 112. Suitable substrates include metal, metal alloy, glass, polymeric, plastic, organic or inorganic work pieces. Depending on the mode of deposition, a monolayer or monolayers of the deposition mixture will form on substrate 112. The preferred method for deposition is Atomic Layer Deposition. However, the system and method of the present invention may be employed with other deposition techniques.
  • [0067]
    Referring again to FIG. 1, following deposition of the deposition mixture, excess mixture is purged out of the system through an exhaust port connected to a vacuum pump that controls the system pressure, gas flow and insures rapid purging of the process chamber 102 after each deposition process. The wafer support 110 is used to support and heat the substrate during a deposition or annealing step. The wafer support typically contains heating and cooling elements formed therein. An external heater (not shown) may also be used to control the temperature of the process chamber. Preferably, the wafer support 110 is a vacuum or electrostatic chuck.
  • [0068]
    Process chamber 102 has an inlet 103 switchably and sequentially capable of supplying other gases used in the process or in cleaning of the chamber. Reactant gases may be conveyed into the chamber via inlet 103. Suitable reactant gases include oxidizing gas, reducing gas, nitridating gas, or mixtures thereof. Other gases which may be conveyed through inlet 103 include carrier or inert gas, or mixtures thereof.
  • [0069]
    In one preferred embodiment, vaporized deposition precursors are mixed in a manifold prior to introduction into the reaction chamber in order to provide a more uniform film and to permit maximum control of the composition of the film. However, it is possible to separately convey each vaporized precursor to a gas inlet, such as an injector and the like, which mixes the gases as they are injected into the chamber, thus eliminating the need for a separate manifold. A variety of mechanical embodiments are suitable in light of the teaching of the present invention, and the present invention is not limited to any one mechanical configuration. The teaching of the present invention provides that at least some mixing of the various different precursors takes place such that a mixture of precursors having different chemical components is present in the process chamber to form a film having multiple components in one mono-layer.
  • [0070]
    A reactant gas may be introduced into the process chamber 102 through inlet 103, to treat and/or react with the monolayer comprising the deposition mixture on the surface of the substrate 112. Reactant gases can be supplied sequentially or simultaneously mixed with the deposition precursors in the gas inlet 114 or directly into the process chamber 102.
  • [0071]
    A variety of reactant gases may be used depending on the application. If the reactant gas is an oxidizing gas, the monolayer is oxidized. If the reactant gas is a reducing gas, the monolayer is reduced. Similarly, if the reactant gas is a nitridating gas, the monolayer is nitridated. Suitable oxidizing gases include ozone, oxygen, singlet oxygen, triplet oxygen, water, peroxides, air, nitrous oxide, nitric oxide, H2O2, and mixtures thereof. Suitable reducing gases include hydrogen. Suitable nitridating gases include ammonia, deuterated ammonia, 15N-ammonia, hydrazine, alkyl hydrazines, nitrogen dioxide, nitrous oxide, nitrogen radical, nitric oxide, N-oxides, amides, amines, or mixtures thereof. In another embodiment, after the deposition precursor has been deposited on substrate 112, substrate 112 can be transferred in vacuum to a second processing unit capable of nitridating, oxidizing, reducing, or annealing the monolayer on substrate 112.
  • [0072]
    In one example, to form a multi-component film comprising HfSiN by ALD, a hafnium and silicon deposition precursors (for example: TEMA-Hf and TEMA-Si, respectively) are vaporized, mixed and conveyed (also referred to as “pulsed) to the process chamber together, along with a nitrogen containing source such as NH3to form HfSiN. The process may be carried out where the Hf and Si deposition precursors are mixed together and pulsed into the process chamber, then purged. The nitrogen source gas (such as NH3) is pulsed and purged. These steps form one ALD cycle to form the HfSiN film. In another embodiment, a further pulse and purge step is performed with an oxidizing agent, such as ozone, in one ALD cycle to form a HfSiON film.
  • [0073]
    In one example the ALD process is carried out at a process temperature in the range of approximately 25 to 800° C., more usually in the range of approximately 50 to 600° C., and most usually in the range of approximately 100 to 500° C. The pressure in the process chamber is in the range of approximately 0.001 mTorr to 600 Torr, more usually in the range of approximately 0.01 mTorr to 100 Torr, and most usually in the range of approximately 0.1 mTorr to 10 Torr. This pressure range covers both the pulse and purge steps. The total inert gas flow rate in the process chamber, including the carrier gas in the bubblers when used, is generally in the range of approximately 0 to 20,000 sccm, and more usually in the range of approximately 0 to 5,000 sccm.
  • [0074]
    Optionally, after the deposition precursor has been deposited on substrate 112, substrate 112 can be transferred in vacuo to a second processing unit capable of nitridating, oxidizing, reducing, or annealing the monolayer on substrate 112.
  • [0075]
    FIG. 2 illustrates a cross-sectional view of a multi-layered gate dielectric of the present invention. The first layer 200 is selected to promote desired properties of high mobility (faster transistor speed) and a stable interface against substrate 112. Suitably, the first layer is a metal silicate or oxide having a high dielectric constant. Preferably, the first layer is a silicon-rich metal silicate. The silicon component in metal silicates of the first layer reduces the formation of interfacial defects by mitigating the incompatibility between pure metals or metal oxides and the interfacial silicon dioxide residue on substrate 112. The metal component in the metal silicate serves to enhance the dielectric properties of the first layer. Suitable metal, metal alloy or mix metal oxides, nitrides, silicates or oxynitrides of the present invention include, but not limited to, Ti, Zr, Hf, Ta, W, Mo, Ni, Si, Cr, Y, La, C, Nb, Zn, Fe, Cu, Al, Sn, Ce, Pr, Sm, Eu, Th, Dy, Ho, Er, Tm, Yb, Lu, Ga, In, Ru, Mn, Sr, Ba, Ca, V, Co, Os, Rh, Ir, Pd, Pt, Bi, Sn, Pb, Tl, Ge or mixtures thereof.
  • [0076]
    One embodiment of the method of the present invention is illustrated in the flowchart of FIG. 3. This example is shown for illustration purposes only and is not meant to limit the invention in any way. In the exemplary embodiment, a first precursor vaporizer is provided having a first precursor comprising Hf (Step 150). A second precursor vaporizer having a second precursor comprising Si is also provided (Step 152). The substrate or wafer is positioned on the chuck in the reaction chamber (Step 154), the process chamber is evacuated (Step 156), and the substrate heated to a predetermined processing temperature (Step 158). As noted above the process temperature is preferably from approximately 50 to 800° C., and more preferably from approximately 100 to 500° C. The first and second precursors are vaporized by bubbling a gas through the reservoirs to form first and second vaporized precursors (Step 160), mixed (Step 162), and flowed to the reaction chamber (Step 164). The mixed first and second vaporized precursors are directed on to the substrate through the gas inlet such as showerhead or injection nozzle (Step 166).
  • [0077]
    The present invention further provides a multi-component film or layer having a composition gradient as illustrated in FIG. 2. Referring to FIGS. 1 and 2 deposition of first layer 200 onto silicon substrate 112 takes place in process chamber 102. In one example, a film of HfSiO is formed wherein hafnium is vaporized in vaporizer 107, and silicon is vaporized in vaporizer 109. Hafnium and silicon deposition precursor vapors are swept into manifold 104 by a carrier gas. Within the manifold, the deposition precursor vapors are mixed and delivered to gas inlet 114 as a deposition mixture. Gas inlet 114 conveys the disposition mixture to the process chamber 102 and the deposition mixture contacts the surface of a substrate 112 and is absorbed on the surface to form a monolayer of the deposition mixture onto substrate 112. After the process chamber 102 is purged with an inert gas or evacuated under vacuum, ozone gas is sequentially pulsed into process chamber 102 through inlet 103. The reactant gas saturates the monolayer on substrate 12 forming an atomic layer comprising hafnium, silicon and oxygen, where the silicon content is higher than hafnium.
  • [0078]
    FIG. 4 illustrates that by varying the flow of deposition precursors 124 and 126, the concentration of silicon relative to hafnium can be tailored to yield multi-component films. FIG. 5 shows that changes in silicon or hafnium concentration are, for the most part, governed by the formula HfxSi1-xO2, where x=0−1.
  • [0079]
    XPS studies on HfxSi1-xO2 films shed light on the bonding arrangement of atoms in the films. FIG. 6 a represents the XPS spectrum of hafnium in the film. Based on the intensity of the absorption bands and the magnitude of the bonding energies, hafnium is predominantly found in a silicate form. Very little amount of impurities such as HfO2 is seen in the spectrum. Now referring to FIG. 6 b, the XPS spectrum of silicon reveals that silicon also exists predominantly as a silicate with no or very little SiO2 formation. The XPS results highlight the advantages of the present invention. That is, the formation of homogeneous hafnium silicate films with no or minimal patches of HfO2 or SiO2.
  • [0080]
    Now referring to FIG. 7, refractive indices of dielectric films of the present invention decrease with increasing silicon content. FIG. 7 shows that heating the films in a N2 atmosphere at 900° C. causes no thermal alterations.
  • [0081]
    FIG. 8 shows that the rate of deposition is temperature dependent. The rate of linear growth of HfxSi1-xO2 increases with temperature. However, above 400° C., the deposition rate increases substantially as the atomic layer deposition (ALD) process adopts a chemical vapor deposition (CVD) mechanism. Cross-sectional Transmission Electron Microscopy (TEM) images of Hf0.58Si0.42O2 film deposited at 400° C. on HF-last silicon substrates, at various thick nesses, show similar interfacial layer thickness measuring approximately 1 nm. Comparing FIGS. 9 a, 9 b and 9 c, each having a dielectric thickness of 2.3 nm, 4.3 nm and 6.5 nm, respectively, the interfacial thickness is independent of the dielectric thickness. This suggests that, when ozone is used as the oxidizing reactant in an ALD process, the oxidation at the interface may take place during the initial stages of film fabrication.
  • [0082]
    Although heating at elevated temperatures does not alter the amorphous state of the dielectric, annealing decreases the interfacial oxide layer. FIG. 10 shows a TEM image of the Hf0.58Si0.42O2 film after annealing. Comparing the thickness of the interfacial oxide layer to FIG. 9, annealing seems to reduce the interfacial layer by 0.3 nm without changing either the capacitance-voltage (CV) or current-voltage (IV). FIG. 11 shows that the films are electrically stable to annealing. Neither capacitance-equivalent thickness (CET) nor the low leakage current densities were greatly affected by the annealing step.
  • [0083]
    Stress hysteresis measurement for a 50 nm thick Hf0.34Si066O2 film, during an anneal to 900° C., was monitored. As shown in FIG. 12, the consistent slope during heat-up indicates a fairly stable difference in thermal expansion between the deposited Hf0.34Si066O2 film and the silicon substrate. At approximately 700° C., the stress becomes more tensile, indicating a change in morphology to a microcrystalline state. Relative to an HfO2 film, deposited by ALD from TEMAHf and O3 at 300° C., which possesses a stress increase at approximately 450° C. (not shown), the increase in film stress transition temperature in HfxSi1-xO2 is attributable to an increase in the silicon content. Thus, an increase in silicon content increases the temperature at which films crystallize.
  • [0084]
    Suitable source of hafnium include hafnium dialkyl amides, hafnium alkoxides, hafnium diketonates or hafnium halides. Suitable sources of silicon include silicon halides, silicon dialkyl amides or amines, silicon alkoxides, silanes, disilanes, siloxanes, aminodisilane, and disilicon halides. Typically, sources of hafnium and silicon are selected having common ligands to prevent complications arising from ligand exchange. Covalently bridged mixed metals, as disclosed in PCT patent application serial number PCT/US03/22236 entitled Molecular Layer Deposition Of Thin Films With Mixed Components, incorporated herein by reference, as well as non-covalently bonded mixed metals may be used as precursors for deposition. Types of non-covalent bonds include hydrogen bonds, dative bonds, metal-metal bonds, metal-π, metal-π*, π-π bonds, sigma-sigma bonds, ionic bonds, Van Der Waals interactions, hydrophobic/hydrophilic interactions, polar bonds or dipole moment interactions. Sources of inert gases include carrier gases such argon, nitrogen, inert gases, or a mixture thereof.
  • [0085]
    Again referring to FIG. 2, a second layer 202 is deposited on the first layer 200, wherein the second layer 202 has a greater concentration of hafnium than silicon, i.e., hafnium>silicon. The higher concentration of hafnium ensures that the overall make-up of the dielectric behaves like a high k hafnium dielectric. The presence of silicon in the second layer 202 creates a gradual stoichiometric transition from first layer 200 so that there are no abrupt compositional interfaces between the individual layers that may cause electrical leakage and defects. Subsequent oxidation with ozone affords second layer 202.
  • [0086]
    In various embodiments of the present invention, a third layer 203 can optionally be deposited comprising primarily hafnium, i.e., hafnium>>silicon, atop second layer 202 to form a stack of dielectric layers having a compositional gradient. Oxidation with an oxidizing reactant yields predominantly hafnium dioxide. Utilizing this approach, a homogeneous film of any gradient, thickness and composition can be fabricated with precision and control.
  • [0087]
    In another aspect, third layer 203 may be nitridated with a nitridating reactant. The inclusion of nitrogen blocks the diffusion of impurities such as boron through the dielectric, and enhances the long-term performance and reliability of the film.
  • [0088]
    In some embodiments, third layer 203 can be nitridated thermally in the presence of ammonia gas as a post-deposition annealing step. Whereas, in other embodiments, third layer 203 can be nitridated using high energy nitrogen particles generated remotely with respect to the process chamber 102. In accordance with one aspect of the present invention, FIG. 13 shows an XPS spectrum for an exemplary post-annealed film with ammonia. Relative to a HfSiO reference also shown in FIG. 13, the presence of the nitrogen peak near 400 eV indicates the incorporation of nitrogen into the HfSiO layer. Measurements at various take-off angles (TOA) detect the presence of HfSiON not only at the surface of the dielectric, but as well as deep within the film.
  • [0089]
    Optionally, if desired, instead of relying on heat to form and anneal the nitride layer, nitridation can be facilitated by light or any combination of light, heat and chemical initiators. For example, in certain embodiments, direct plasma, remote plasma, downstream plasma, ultraviolet photon energy, or a combination thereof, can be used to facilitate nitridation. Activation energy sources include plasma, light, laser, radical, and microwave energy sources, and mixtures thereof.
  • [0090]
    As previously mentioned in a separate embodiment, suitable nitrogen sources include ammonia, deuterated ammonia, 15N enriched ammonia, amines, amides, nitrogen gas, hydrazines, alky hydrazines, nitrous oxide, nitric oxide, nitrogen radicals, N-oxides, or a mixture thereof.
  • [0091]
    In yet another aspect of the present invention, although related to the nitridation of films, an ambient method of nitridating dielectrics is provided. FIG. 14 shows that the rate of HfO2 deposition, arising from the reaction between hafnium dialkyl amide precursors and ozone, increases, surprisingly, with a decrease in reaction temperature. In view of ozone's reactivity toward hafnium dialky amide, HfSiOx 300 was deposited onto substrate precursor 112 as shown in FIG. 14 by vaporizing hafnium and silicon in vaporizers 107 and 109, respectively, of FIG. 1. Ozone is supplied through inlet 103 into the process chamber 102 housing substrate 112. Oxidation occurs rapidly at relatively low temperatures as in FIG. 16 a to afford hafnium oxide 302. To protect layer 302 from boron diffusion from the gate electrode, an oxynitride layer 304 is desirable atop metal oxide 302.
  • [0092]
    There are two methods for depositing oxynitride layer 304. In the first method, as depicted in FIG. 16 a, the deposition precursor or precursors 124, 126 are vaporized and injected into process chamber 102 forming a monolayer of deposition mixture on substrate 112.
  • [0093]
    Now referring to FIG. 16 a, despite a low temperature oxidation that affords oxide 302, the subsequently thermal oxynitridation anneal at 800° C. with ammonia is tolerable, yet unfavorable from a process stand point. Structurally, such high annealing temperatures pose a greater concern. That is, the crystallization of oxide layer 302, leading to possible intrinsic defects deep within or at the grain boundaries of oxide 302.
  • [0094]
    In the preferred embodiment of the present invention, the second method for depositing oxynitride is shown in FIG. 16 b. The method in FIG. 16 b, relative to the method in FIG. 16 a, is a more economical pathway to oxynitride 304. Since ozone reacts readily with metal dialkyl amides, a deposition mixture is first deposited onto substrate 112 and treated in-situ with ammonia sequentially. Following the formation of nitride 303 at relatively low temperatures, oxidation with ozone drives the reaction to completion affording oxynitride 304.
  • [0095]
    In some embodiments of the present invention, deuterated ammonia or 15N-ammonia is preferred.
  • [0096]
    FIG. 17 shows the compositional profile below the surface of oxynitride 304. Nitrogen concentration is greatest on the surface of the film, but gradually decrease below the surface until the HfO2 layer is reached. With further penetration into the film, the concentration of HfO2 302 decreases giving away to HfSiOx 300, until the interfacial layer of the silicon substrate 112 is reached.
  • [0097]
    In accordance with the present invention, numerous layers of HfSiON having different film thickness and nitrogen or oxygen concentration can be deposited. While specific examples describing the formation of SiO2, HfO2, HfSiOx, HfN, SiN, SiON and HfSiON are shown herein, it will be apparent to those of ordinary skill in the art that the inventive method and ALD system may be employed to generate any thickness, composition, or types of thin films comprising metal, metal alloys or mix metals oxides, silicates, nitrides, oxynitrides, or combinations thereof.
  • [0098]
    The foregoing description of specific embodiments of the invention have been presented for the purpose of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications, embodiments, and variations are possible in lights of the above teaching. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.
Citat från patent
citerade patent Registreringsdatum Publiceringsdatum Sökande Titel
US3911176 *2 jan 19747 okt 1975Rca CorpMethod for vapor-phase growth of thin films of lithium niobate
US4668531 *25 jun 198626 maj 1987Permelec Electrode Ltd.Method for manufacture of electrode
US4772346 *29 okt 198720 sep 1988International Business Machines CorporationMethod of bonding inorganic particulate material
US5051278 *10 jul 198924 sep 1991Eastman Kodak CompanyMethod of forming metal fluoride films by the decomposition of metallo-organic compounds in the presence of a fluorinating agent
US5130172 *26 okt 198914 jul 1992The Regents Of The University Of CaliforniaLow temperature organometallic deposition of metals
US5185317 *25 apr 19919 feb 1993Northwestern UniversityMethod of forming superconducting Tl-Ba-Ca-Cu-O films
US5271957 *3 nov 199221 dec 1993Eastman Kodak CompanyChemical vapor deposition of niobium and tantalum oxide films
US5686151 *20 feb 199611 nov 1997Kabushiki Kaisha ToshibaMethod of forming a metal oxide film
US5688565 *7 jun 199518 nov 1997Symetrix CorporationMisted deposition method of fabricating layered superlattice materials
US5789027 *12 nov 19964 aug 1998University Of MassachusettsMethod of chemically depositing material onto a substrate
US5843516 *16 sep 19961 dec 1998Symetrix CorporationLiquid source formation of thin films using hexamethyl-disilazane
US5879459 *29 aug 19979 mar 1999Genus, Inc.Vertically-stacked process reactor and cluster tool system for atomic layer deposition
US6030900 *12 jul 199629 feb 2000Siemens AktiengesellschaftProcess for generating a space in a structure
US6099903 *19 maj 19998 aug 2000Research Foundation Of State University Of New YorkMOCVD processes using precursors based on organometalloid ligands
US6203613 *19 okt 199920 mar 2001International Business Machines CorporationAtomic layer deposition with nitrate containing precursors
US6214729 *1 sep 199810 apr 2001Micron Technology, Inc.Metal complexes with chelating C-, N-donor ligands for forming metal-containing films
US6465371 *20 jun 200115 okt 2002Hyundai Electronics Industries Co., Ltd.Method for manufacturing zirconium oxide film for use in semiconductor device
US6509280 *13 feb 200221 jan 2003Samsung Electronics Co., Ltd.Method for forming a dielectric layer of a semiconductor device
US6511539 *8 sep 199928 jan 2003Asm America, Inc.Apparatus and method for growth of a thin film
US6552209 *24 jun 200222 apr 2003Air Products And Chemicals, Inc.Preparation of metal imino/amino complexes for metal oxide and metal nitride thin films
US6642131 *16 apr 20024 nov 2003Matsushita Electric Industrial Co., Ltd.Method of forming a silicon-containing metal-oxide gate dielectric by depositing a high dielectric constant film on a silicon substrate and diffusing silicon from the substrate into the high dielectric constant film
US20020058843 *22 aug 200116 maj 2002Min Yo SepNovel group IV metal precursors and a method of chemical vapor deposition using the same
US20020115275 *13 feb 200222 aug 2002Samsung Electronics Co., Ltd.Method for forming a dielectric layer of a semiconductor device and a capacitor using the same
US20020187644 *18 sep 200112 dec 2002Baum Thomas H.Source reagent compositions for CVD formation of gate dielectric thin films using amide precursors and method of using same
US20030040196 *29 okt 200127 feb 2003Lim Jung WookMethod of forming insulation layer in semiconductor devices for controlling the composition and the doping concentration
US20030232511 *19 sep 200218 dec 2003Applied Materials, Inc.ALD metal oxide deposition process using direct oxidation
US20050070126 *15 jun 200431 mar 2005Yoshihide SenzakiSystem and method for forming multi-component dielectric films
US20050255243 *24 jun 200517 nov 2005Aviza Technology, Inc.System and method for forming multi-component dielectric films
US20060228888 *18 aug 200312 okt 2006Lee Sang-InAtomic layer deposition of high k metal silicates
Hänvisningar finns i följande patent
citeras i Registreringsdatum Publiceringsdatum Sökande Titel
US7235502 *31 mar 200526 jun 2007Freescale Semiconductor, Inc.Transitional dielectric layer to improve reliability and performance of high dielectric constant transistors
US7326656 *24 feb 20065 feb 2008Intel CorporationMethod of forming a metal oxide dielectric
US7495264 *7 dec 200624 feb 2009Nec CorporationSemiconductor device with high dielectric constant insulating film and manufacturing method for the same
US753143722 feb 200612 maj 2009Intel CorporationMethod of forming metal gate electrodes using sacrificial gate electrode material and sacrificial gate dielectric material
US765915831 mar 20089 feb 2010Applied Materials, Inc.Atomic layer deposition processes for non-volatile memory devices
US767819428 nov 200616 mar 2010Applied Materials, Inc.Method for providing gas to a processing chamber
US76829466 nov 200623 mar 2010Applied Materials, Inc.Apparatus and process for plasma-enhanced atomic layer deposition
US771439725 jul 200611 maj 2010Intel CorporationTri-gate transistor device with stress incorporation layer and method of fabrication
US773695626 mar 200815 jun 2010Intel CorporationLateral undercut of metal gate in SOI device
US775974631 mar 200620 jul 2010Tokyo Electron LimitedSemiconductor device with gate dielectric containing aluminum and mixed rare earth elements
US776726229 sep 20063 aug 2010Tokyo Electron LimitedNitrogen profile engineering in nitrided high dielectric constant films
US777550831 okt 200617 aug 2010Applied Materials, Inc.Ampoule for liquid draw and vapor draw with a continuous level sensor
US778078811 mar 200524 aug 2010Applied Materials, Inc.Gas delivery apparatus for atomic layer deposition
US77817714 feb 200824 aug 2010Intel CorporationBulk non-planar transistor having strained enhanced mobility and methods of fabrication
US779062816 aug 20077 sep 2010Tokyo Electron LimitedMethod of forming high dielectric constant films using a plurality of oxidation sources
US779454426 okt 200714 sep 2010Applied Materials, Inc.Control of gas flow and delivery to suppress the formation of particles in an MOCVD/ALD system
US77980965 maj 200621 sep 2010Applied Materials, Inc.Plasma, UV and ion/neutral assisted ALD or CVD in a batch tool
US781673731 mar 200619 okt 2010Tokyo Electron LimitedSemiconductor device with gate dielectric containing mixed rare earth elements
US782051328 okt 200826 okt 2010Intel CorporationNonplanar semiconductor device with partially or fully wrapped around gate electrode and methods of fabrication
US782548123 dec 20082 nov 2010Intel CorporationField effect transistor with narrow bandgap source and drain regions and method of fabrication
US78507796 nov 200614 dec 2010Applied Materisals, Inc.Apparatus and process for plasma-enhanced atomic layer deposition
US78678962 apr 200911 jan 2011Applied Materials, Inc.Sequential deposition of tantalum nitride using a tantalum-containing precursor and a nitrogen-containing precursor
US787147026 jun 200618 jan 2011Applied Materials, Inc.Substrate support lift mechanism
US78796752 maj 20081 feb 2011Intel CorporationField effect transistor with metal source/drain regions
US78935064 aug 201022 feb 2011Intel CorporationField effect transistor with narrow bandgap source and drain regions and method of fabrication
US789804114 sep 20071 mar 2011Intel CorporationBlock contact architectures for nanoscale channel transistors
US79020143 jan 20078 mar 2011Intel CorporationCMOS devices with a single work function gate electrode and method of fabrication
US791516729 sep 200529 mar 2011Intel CorporationFabrication of channel wraparound gate structure for field-effect transistor
US796079420 dec 200714 jun 2011Intel CorporationNon-planar pMOS structure with a strained channel region and an integrated strained CMOS flow
US796451521 dec 200721 jun 2011Tokyo Electron LimitedMethod of forming high-dielectric constant films for semiconductor devices
US797297827 jun 20085 jul 2011Applied Materials, Inc.Pretreatment processes within a batch ALD reactor
US798928018 dec 20082 aug 2011Intel CorporationDielectric interface for group III-V semiconductor device
US801244231 mar 20066 sep 2011Tokyo Electron LimitedMethod of forming mixed rare earth nitride and aluminum nitride films by atomic layer deposition
US804390714 jan 201025 okt 2011Applied Materials, Inc.Atomic layer deposition processes for non-volatile memory devices
US806781824 nov 201029 nov 2011Intel CorporationNonplanar device with thinned lower body portion and method of fabrication
US80719838 maj 20096 dec 2011Intel CorporationSemiconductor device structures and methods of forming semiconductor structures
US807624130 sep 200913 dec 2011Tokyo Electron LimitedMethods for multi-step copper plating on a continuous ruthenium film in recessed features
US808481812 jan 200627 dec 2011Intel CorporationHigh mobility tri-gate devices and methods of fabrication
US809730031 mar 200617 jan 2012Tokyo Electron LimitedMethod of forming mixed rare earth oxynitride and aluminum oxynitride films by atomic layer deposition
US811048911 apr 20077 feb 2012Applied Materials, Inc.Process for forming cobalt-containing materials
US811921021 maj 200421 feb 2012Applied Materials, Inc.Formation of a silicon oxynitride layer on a high-k dielectric material
US814689631 okt 20083 apr 2012Applied Materials, Inc.Chemical precursor ampoule for vapor deposition processes
US81836464 feb 201122 maj 2012Intel CorporationField effect transistor with narrow bandgap source and drain regions and method of fabrication
US818797015 dec 201029 maj 2012Applied Materials, Inc.Process for forming cobalt and cobalt silicide materials in tungsten contact applications
US819356711 dec 20085 jun 2012Intel CorporationProcess for integrating planar and non-planar CMOS transistors on a bulk substrate and article made thereby
US82687096 aug 201018 sep 2012Intel CorporationIndependently accessed double-gate and tri-gate transistors in same process flow
US827362629 sep 201025 sep 2012Intel CorporationnNonplanar semiconductor device with partially or fully wrapped around gate electrode and methods of fabrication
US828299226 okt 20079 okt 2012Applied Materials, Inc.Methods for atomic layer deposition of hafnium-containing high-K dielectric materials
US82941801 mar 201123 okt 2012Intel CorporationCMOS devices with a single work function gate electrode and method of fabrication
US832375421 maj 20044 dec 2012Applied Materials, Inc.Stabilization of high-k dielectric materials
US8339037 *23 mar 200525 dec 2012Panasonic CorporationOrganic light emitting device with reduced angle dependency
US834327912 maj 20051 jan 2013Applied Materials, Inc.Apparatuses for atomic layer deposition
US836256623 jun 200829 jan 2013Intel CorporationStress in trigate devices using complimentary gate fill materials
US836813523 apr 20125 feb 2013Intel CorporationField effect transistor with narrow bandgap source and drain regions and method of fabrication
US839992214 sep 201219 mar 2013Intel CorporationIndependently accessed double-gate and tri-gate transistors
US840516426 apr 201026 mar 2013Intel CorporationTri-gate transistor device with stress incorporation layer and method of fabrication
US84919678 sep 200823 jul 2013Applied Materials, Inc.In-situ chamber treatment and deposition process
US850235123 sep 20116 aug 2013Intel CorporationNonplanar device with thinned lower body portion and method of fabrication
US856342426 apr 201222 okt 2013Applied Materials, Inc.Process for forming cobalt and cobalt silicide materials in tungsten contact applications
US858125820 okt 201112 nov 2013Intel CorporationSemiconductor device structures and methods of forming semiconductor structures
US86179453 feb 201231 dec 2013Intel CorporationStacking fault and twin blocking barrier for integrating III-V on Si
US866469428 jan 20134 mar 2014Intel CorporationField effect transistor with narrow bandgap source and drain regions and method of fabrication
US866877610 jun 201011 mar 2014Applied Materials, Inc.Gas delivery apparatus and method for atomic layer deposition
US874173325 jan 20133 jun 2014Intel CorporationStress in trigate devices using complimentary gate fill materials
US87490263 jun 201310 jun 2014Intel CorporationNonplanar device with thinned lower body portion and method of fabrication
US881639420 dec 201326 aug 2014Intel CorporationField effect transistor with narrow bandgap source and drain regions and method of fabrication
US882163729 jan 20082 sep 2014Applied Materials, Inc.Temperature controlled lid assembly for tungsten nitride deposition
US89334588 okt 201313 jan 2015Intel CorporationSemiconductor device structures and methods of forming semiconductor structures
US901883419 nov 201228 apr 2015Panasonic CorporationOrganic light emitting device
US903290616 okt 200719 maj 2015Applied Materials, Inc.Apparatus and process for plasma-enhanced atomic layer deposition
US904831421 aug 20142 jun 2015Intel CorporationField effect transistor with narrow bandgap source and drain regions and method of fabrication
US905164129 aug 20089 jun 2015Applied Materials, Inc.Cobalt deposition on barrier surfaces
US91905188 maj 201417 nov 2015Intel CorporationNonplanar device with thinned lower body portion and method of fabrication
US920907420 maj 20158 dec 2015Applied Materials, Inc.Cobalt deposition on barrier surfaces
US92247548 maj 201429 dec 2015Intel CorporationStress in trigate devices using complimentary gate fill materials
US933730718 nov 201010 maj 2016Intel CorporationMethod for fabricating transistor with thinned channel
US93685831 maj 201514 jun 2016Intel CorporationField effect transistor with narrow bandgap source and drain regions and method of fabrication
US938518018 dec 20145 jul 2016Intel CorporationSemiconductor device structures and methods of forming semiconductor structures
US941889015 maj 201416 aug 2016Applied Materials, Inc.Method for tuning a deposition rate during an atomic layer deposition process
US945009211 nov 201520 sep 2016Intel CorporationStress in trigate devices using complimentary gate fill materials
US961408310 jun 20164 apr 2017Intel CorporationField effect transistor with narrow bandgap source and drain regions and method of fabrication
US974180916 sep 201522 aug 2017Intel CorporationNonplanar device with thinned lower body portion and method of fabrication
US974839124 feb 201729 aug 2017Intel CorporationField effect transistor with narrow bandgap source and drain regions and method of fabrication
US976172414 jun 201612 sep 2017Intel CorporationSemiconductor device structures and methods of forming semiconductor structures
US980619329 aug 201631 okt 2017Intel CorporationStress in trigate devices using complimentary gate fill materials
US980619514 mar 201631 okt 2017Intel CorporationMethod for fabricating transistor with thinned channel
US20050271812 *12 maj 20058 dec 2005Myo Nyi OApparatuses and methods for atomic layer deposition of hafnium-containing high-k dielectric materials
US20060138552 *22 feb 200629 jun 2006Brask Justin KNonplanar transistors with metal gate electrodes
US20060138553 *24 feb 200629 jun 2006Brask Justin KNonplanar transistors with metal gate electrodes
US20060220157 *31 mar 20055 okt 2006Freescale Semiconductor, Inc.Transitional dielectric layer to improve reliability and performance of high dielectric constant transistors
US20070090450 *7 dec 200626 apr 2007Nec CorporationSemiconductor device with high dielectric constant insulating film and manufacturing method for the same
US20070235821 *31 mar 200611 okt 2007Tokyo Electron LimitedSemiconductor device with gate dielectric containing mixed rare earth elements
US20070235822 *31 mar 200611 okt 2007Tokyo Electron LimitedSemiconductor device with gate dielectric containing aluminum and mixed rare earth elements
US20070237697 *31 mar 200611 okt 2007Tokyo Electron LimitedMethod of forming mixed rare earth oxide and aluminate films by atomic layer deposition
US20070237698 *31 mar 200611 okt 2007Tokyo Electron LimitedMethod of forming mixed rare earth nitride and aluminum nitride films by atomic layer deposition
US20070237699 *31 mar 200611 okt 2007Tokyo Electron LimitedMethod of forming mixed rare earth oxynitride and aluminum oxynitride films by atomic layer deposition
US20080081113 *29 sep 20063 apr 2008Tokyo Electron LimitedNitrogen profile engineering in nitrided high dielectric constant films
US20080272689 *23 mar 20056 nov 2008Organic Light Emitting DeviceOrganic Light Emitting Device
US20090047798 *16 aug 200719 feb 2009Tokyo Electron LimitedMethod of forming high dielectric constant films using a plurality of oxidation sources
US20090163012 *21 dec 200725 jun 2009Tokyo Electron LimitedMethod of forming high-dielectric constant films for semiconductor devices
US20100237395 *17 maj 201023 sep 2010Tokyo Electron LimitedSemiconductor device with gate dielectric containing mixed rare earth elements
US20110076390 *30 sep 200931 mar 2011Tokyo Electron LimitedMethods for multi-step copper plating on a continuous ruthenium film in recessed features
US20110165328 *16 mar 20117 jul 2011Tokyo Electron LimitedMethod of forming mixed rare earth oxide and aluminate films by atomic layer deposition
Klassificeringar
USA-klassificering428/446, 257/E21.269, 257/E21.278, 257/E21.279, 257/E21.267
Internationell klassificeringC23C16/455, C23C16/30, H01L21/316, H01L21/314, C23C16/44, C23C16/40, C23C16/02
Kooperativ klassningC23C16/401, H01L21/3141, C23C16/308, H01L21/3145, C23C16/029, H01L21/3142, H01L21/31645, H01L21/3143, H01L21/31608, C23C16/45531, H01L21/31612
Europeisk klassificeringH01L21/314A2, H01L21/314B2, C23C16/40B, C23C16/30E, C23C16/02H4, H01L21/314A, C23C16/455F2B4