WO2009143452A1 - High-k dielectric films and methods of producing using cerium-based precursors - Google Patents

High-k dielectric films and methods of producing using cerium-based precursors Download PDF

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WO2009143452A1
WO2009143452A1 PCT/US2009/045024 US2009045024W WO2009143452A1 WO 2009143452 A1 WO2009143452 A1 WO 2009143452A1 US 2009045024 W US2009045024 W US 2009045024W WO 2009143452 A1 WO2009143452 A1 WO 2009143452A1
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cerium
zirconium
hafnium
group
oxide
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French (fr)
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Paul Raymond Chalker
Peter Nicholas Heys
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Sigma-Aldrich Co.
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104Forming layers
    • H01L21/02107Forming insulating materials on a substrate
    • H01L21/02109Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
    • H01L21/02205Forming 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
    • CCHEMISTRY; METALLURGY
    • C23COATING 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
    • C23CCOATING 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
    • C23C16/00Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22Chemical 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
    • C23C16/30Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/40Oxides
    • C23C16/405Oxides of refractory metals or yttrium
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    • H01L21/02172Forming 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 at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides
    • H01L21/02175Forming 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 at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides characterised by the metal
    • H01L21/02181Forming 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 at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides characterised by the metal the material containing hafnium, e.g. HfO2
    • HELECTRICITY
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    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
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    • H01L21/02112Forming 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
    • H01L21/02172Forming 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 at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides
    • H01L21/02175Forming 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 at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides characterised by the metal
    • H01L21/02186Forming 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 at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides characterised by the metal the material containing titanium, e.g. TiO2
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    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104Forming layers
    • H01L21/02107Forming insulating materials on a substrate
    • H01L21/02109Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
    • H01L21/02112Forming 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
    • H01L21/02172Forming 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 at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides
    • H01L21/02175Forming 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 at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides characterised by the metal
    • H01L21/02189Forming 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 at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides characterised by the metal the material containing zirconium, e.g. ZrO2
    • HELECTRICITY
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    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104Forming layers
    • H01L21/02107Forming insulating materials on a substrate
    • H01L21/02109Forming insulating materials on a substrate characterised by the type of layer, e.g. type of material, porous/non-porous, pre-cursors, mixtures or laminates
    • H01L21/02112Forming 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
    • H01L21/02172Forming 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 at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides
    • H01L21/02175Forming 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 at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides characterised by the metal
    • H01L21/02194Forming 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 at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides characterised by the metal the material containing more than one metal element
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    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104Forming layers
    • H01L21/02107Forming insulating materials on a substrate
    • H01L21/02225Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
    • H01L21/0226Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process
    • H01L21/02263Forming 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
    • H01L21/02271Forming 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
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
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    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104Forming layers
    • H01L21/02107Forming insulating materials on a substrate
    • H01L21/02225Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer
    • H01L21/0226Forming insulating materials on a substrate characterised by the process for the formation of the insulating layer formation by a deposition process
    • H01L21/02263Forming 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
    • H01L21/02271Forming 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
    • H01L21/0228Forming 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

Definitions

  • the present invention relates to methods of forming high- ⁇ dielectric thin metallic films, improving such films, and a lattice capable of forming such films.
  • Various organometallic precursors are used to form high- ⁇ dielectric thin metal films for use in the semiconductor industry.
  • Various deposition processes are used to form the metal films, such as chemical vapor deposition ("CVD”) or atomic layer deposition (“ALD”), also known as atomic layer epitaxy.
  • CVD chemical vapor deposition
  • ALD atomic layer deposition
  • CVD is a chemical process whereby precursors are deposited on a substrate to form a solid thin film.
  • the precursors are passed over a substrate (wafer) within a low pressure or ambient pressure reaction chamber.
  • the precursors react and/or decompose on the substrate surface creating a thin film of deposited material.
  • Volatile by-products are removed by gas flow through the reaction chamber.
  • the deposited film thickness can be difficult to control because it depends on coordination of many parameters such as temperature, pressure, gas flow volumes and uniformity, chemical depletion effects and time.
  • ALD is a chemical process which separates the precursors during the reaction.
  • the first precursor is passed over the substrate producing a monolayer on the substrate. Any excess unreacted precursor is pumped out of the reaction chamber.
  • a second precursor is then passed over the substrate and reacts with the first precursor, forming a second monolayer of film over the first-formed film on the substrate surface. This cycle is repeated to create a film of desired thickness.
  • ALD film growth is self-limited and based on surface reactions, creating uniform depositions that can be controlled at the nanometer- thickness scale.
  • Zirconia, hafnia and TiO 2 have been used to create dielectric films, generally to replace silicon dioxide gates for use in the semiconductor industry. Replacing silicon dioxide with a high- ⁇ dielectric material allows increased gate capacitance without concomitant leakage effects.
  • the method comprises delivering at least one metal-source precursor and at least one cerium precursor to a substrate, wherein the at least one cerium precursor corresponds in structure to Formula I:
  • L is a cyclopentadienyl ring optionally substituted with one or more substituents selected from the group consisting of alkyl, alkoxy and NRiR 2 ; or L is alkoxy;
  • Ri and R 2 are independently hydrogen or alkyl; and x is 3 or 4.
  • the method comprises using at least one cerium precursor to form a high- ⁇ dielectric film for use in the semiconductor device, wherein the at least one cerium precursor corresponds in structure to Formula I.
  • the method comprises adding at least one cerium precursor to the high- ⁇ dielectric material wherein the at least one cerium precursor corresponds in structure to Formula I.
  • a high- ⁇ dielectric film-forming lattice wherein the lattice is comprised of hafnium oxide, titanium oxide or mixtures thereof and the lattice contains cerium atoms.
  • high- ⁇ dielectric refers to a material, such as a metal-containing film, with a higher dielectric constant (K) when compared to silicon dioxide (which has a dielectric constant of about 3.7).
  • a high- ⁇ dielectric film is used in semiconductor manufacturing processes to replace the silicon dioxide gate dielectric.
  • a high- ⁇ dielectric film may be referred to as having a "high- ⁇ gate property" when the dielectric film is used as a gate material and has at least a higher dielectric constant than silicon dioxide.
  • the term "relative permittivity" is synonymous with dielectric constant (K).
  • the term "vapor deposition process" is used to refer to any type of vapor deposition technique such as CVD or ALD.
  • CVD may take the form of liquid injection CVD.
  • ALD may be either photo-assisted ALD or liquid injection ALD.
  • precursor refers to an organometallic molecule, complex and/or compound which is deposited or delivered to a substrate to form a thin film by a vapor deposition process such as CVD or ALD.
  • alkyl refers to a saturated hydrocarbon chain of 1 to 10 carbon atoms in length, such as, but not limited to, methyl, ethyl, propyl and butyl.
  • the alkyl group may be straight-chain or branched-chain.
  • propyl encompasses both w-propyl and /so-propyl; butyl encompasses w-butyl, sec-butyl, zso-butyl and tert-butyl.
  • alkoxy refers to a substituent, i.e., -O-alkyl.
  • substituent include methoxy (-0-CH 3 ), ethoxy, etc.
  • the alkyl portion may be straight-chain or branched- chain.
  • propoxy encompasses both w-propoxy and iso- propoxy; butoxy encompasses w-butoxy, zso-butoxy, sec-butoxy, and tert-butoxy.
  • cyclopentadienyl or "Cp” (C 5 H 5 ) refers to a 5- membered carbon ring which is bound to a transition metal. As used herein, all five carbon atoms of the Cp ligand are bound to the metal center in ⁇ 5 -coordination by ⁇ bonding.
  • a method to form a high- ⁇ dielectric film by a vapor deposition process comprises delivering at least one metal- source precursor and at least one cerium precursor to a substrate, wherein the at least one cerium precursor corresponds in structure to Formula I:
  • L is a cyclopentadienyl ring optionally substituted with one or more substituents selected from the group consisting of alkyl, alkoxy and NRiR 2 ; or L is alkoxy; Ri and R 2 are independently hydrogen or alkyl; and x is 3 or 4.
  • L is a cyclopentadienyl ring optionally substituted with one or more substituents such as alkyl, alkoxy and NRiR 2 .
  • the cyclopentadienyl ring is substituted with one or more substituents such as alkyl, alkoxy and NRiR 2 .
  • L is a cyclopentadienyl ring and x is 3, therefore in this embodiment there are three cyclopentadienyl rings attached to cerium.
  • L is alkoxy group such as methoxy, ethoxy, propoxy, butoxy or pentoxy.
  • L is alkoxy and x is 4, therefore in this embodiment there are four alkoxy groups attached to cerium.
  • At least one cerium precursor examples include, without limitation:
  • any metal-source precursor suitable for forming a film may be used according to the invention.
  • the at least one metal-source precursor is compatible with the at least one cerium precursor.
  • the at least one metal-source precursor may be compatible with the at least one cerium precursor for purposes of depositing a metal oxide film with the composition Ce x Mi_ x O y where M is either Hf, Zr or Ti; x has a value between about zero and about 0.5; and y has a value less than about 2.
  • Examples of the at least one metal-source precursor include, without limitation: a metal amide, such as Hafnium dimethylamide, Zirconium dimethylamide, Titanium dimethylamide, Hafnium ethylmethylamide, Zirconium ethylmethylamide, Titanium ethylmethylamide, Hafnium diethylamide, Zirconium diethylamide and Titanium diethylamide; a metal alkoxide, such as Hafnium t-butoxide, Zirconium t-butoxide, Titanium t-butoxide, Hafnium i-propoxide, Zirconium i-propoxide, Titanium i-propoxide, Hafnium bis t-butoxy bis 2-methyl-2-methoxy propoxide, Zirconium bis t-butoxy bis 2-methyl-2-methoxy propoxide, Titanium bis t-butoxy bis 2-methyl-2-methoxy propoxide, Zirconium bis t-butoxy bis
  • the high- ⁇ dielectric film formed by a method of the invention may comprise:
  • At least one cerium precursor is used in a vapor deposition process with at least one hafnium precursor to create a cerium-doped hafnium oxide film.
  • at least one cerium precursor is used in a vapor deposition process with at least one zirconium precursor to create a cerium-doped zirconium oxide film.
  • At least one cerium precursor is used in a vapor deposition process with at least one titanium precursor to create a cerium-doped titanium oxide film.
  • a cerium precursor is used in a vapor deposition process with at least one hafnium precursor, zirconium precursor and/or titanium precursor to create a cerium doped "mixed" metal oxide film.
  • a "mixed" metal oxide film refers to a metal oxide film comprising cerium and one or more of the following: hafnium oxide, zirconium oxide and titanium oxide.
  • the method of the invention creates either hafnium oxide, zirconium oxide, titanium oxide or a mixed metal oxide dielectric film that contains from about 0.5 to about 35 atomic metal % cerium.
  • the metal oxide or mixed metal oxide film contains from about 5 to about 20 atomic metal % cerium.
  • the metal oxide or mixed metal oxide film contains from about 8 to about 12 atomic metal % cerium.
  • the at least one metal source precursor and/or the at least one cerium precursor may be dissolved in an appropriate hydrocarbon or amine solvent.
  • Appropriate hydrocarbon solvents include, but are not limited to aliphatic hydrocarbons, such as hexane, heptane and nonane; aromatic hydrocarbons, such as toluene and xylene; aliphatic and cyclic ethers, such as diglyme, triglyme and tetraglyme.
  • appropriate amine solvents include, without limitation, octylamine and N 5 N- dimethyldodecylamine.
  • a precursor may be dissolved in toluene to yield a 0.05 to IM solution.
  • the at least one cerium precursor is dissolved in an organic solvent, such as toluene, heptane, octane, nonane or tetrahydrofuran (THF).
  • an organic solvent such as toluene, heptane, octane, nonane or tetrahydrofuran (THF).
  • THF tetrahydrofuran
  • the cerium-doped films of the invention can be formed by chemical vapor deposition.
  • the chemical vapor deposition is liquid injection chemical vapor deposition.
  • the cerium-doped films of the invention can be formed by atomic layer deposition.
  • the atomic layer deposition is photo-assisted atomic layer deposition.
  • the atomic layer deposition is liquid injection atomic layer deposition.
  • each precursor is deposited and/or delivered onto a substrate in pulses alternating with pulses of an oxygen source.
  • Any suitable oxygen source may be used, for example, H 2 O, O 2 or ozone.
  • each precursor is deposited onto a substrate in pulses with a continuous supply of the oxygen source such as H 2 O, O 2 or ozone.
  • the oxygen source such as H 2 O, O 2 or ozone.
  • the cerium-doped high- ⁇ dielectric film has a relative permittivity of about 20 to about 100, particularly from about 40 to about
  • the high- ⁇ dielectric film is capable of maintaining a relative permittivity of about 20 to about 100 at frequencies of about IKHz to about IGHz.
  • a variety of substrates can be used in the methods of the present invention.
  • the precursors according to Formula I may be deposited on substrates such as, but not limited to, silicon, silicon oxide, silicon nitride, tantalum, tantalum nitride, or copper.
  • a method is provided to improve the high- ⁇ gate property of a semiconductor device.
  • the method comprises using at least one cerium precursor to form a high- ⁇ dielectric film for use in the semiconductor device, wherein the at least one cerium precursor corresponds in structure to Formula I above.
  • Including at least one cerium precursor according to Formula I in a metal oxide film improves the high- ⁇ gate property by either increasing the dielectric constant, allowing longer maintenance of a high dielectric constant or both, when compared to the particular metal oxide film without the at least one cerium precursor. This improves the high- ⁇ gate property of the semiconductor device by increasing gate capacitance and improving permittivity for faster transistors and smaller devices.
  • the dielectric constant can be increased about 20 to about 50 units by using at least one cerium precursor according to Formula I; or a high dielectric constant can be maintained at about IKHz to about IGHz, when compared to not using at least one cerium precursor according to Formula I.
  • a method is provided to stabilize a high- ⁇ dielectric material.
  • the method comprises adding at least one cerium precursor to the high- ⁇ dielectric material wherein the at least one cerium precursor corresponds in structure to Formula (I) above.
  • stabilize refers generally to altering the high- K dielectric material such that the high- ⁇ dielectric material is able to maintain a high dielectric constant at frequencies of about IKHz to about IGHz.
  • the cerium-doped high- ⁇ dielectric film has a relative permittivity of about 20 to about 100, particularly from about 40 to about 70. Further, the high- ⁇ dielectric film is capable of maintaining a relative permittivity of about 20 to about 100 at frequencies of about IKHz to about IGHz.
  • the high- ⁇ dielectric material may be any material wherein stabilization is needed to improve or maintain a high dielectric constant.
  • the high- ⁇ dielectric material may be provided by a film composed of one or more of hafnium oxide, zirconium oxide, titanium oxide or a "mixed" metal oxide, for example, a hafnium, zirconium and/or titanium oxide mixture. Additionally, if three metals are present, then a "ternary" mixed metal oxide film can be stabilized.
  • hafnium, zirconium, or titanium with a +3-oxidation-state rare earth element causes or permits 'dielectric relaxation' in the film-forming materials or film thereby formed.
  • High frequencies cause the dielectric constant (or relative permittivity) of the material to decrease, which is known as dielectric relaxation. It is hypothesized that dielectric relaxation occurs because substitution of hafnium, zirconium or titanium with the +3 element in the lattice causes an oxygen vacancy in order to maintain balanced charge.
  • a hafnium oxide, zirconium oxide, titanium oxide or mixed oxide film can be created using a precursor as disclosed herein such that cerium (IV) is incorporated into the lattice.
  • the high- ⁇ dielectric material is stabilized by stabilizing the metastable phase of the metal used.
  • pure zirconium oxide and hafnium oxide exhibit a stable monoclinic crystalline phase with dielectric constant typically in the range of about 18 to about 22.
  • the metastable phases such as tetragonal and cubic crystal structures of these materials, have high permittivities.
  • some of the Group IV metal may be replaced with one or more cerium precursors of Formula I which can adopt a +4 charge and may obviate the formation of charged oxygen ion vacancies.
  • cerium precursor(s) to stabilize different phases also has implications for radiation hardness, as the resistance to radiation can be increased which is very useful for space applications where resistance to degradation by various forms of radiation is key to device lifetimes and efficiencies. Therefore, these stabilized high- ⁇ dielectric materials are useful in semiconductor devices and are useful for computer memory and logic applications, such as dynamic random access memory (DRAM) and complementary metal oxide semi-conductor (CMOS) circuitry.
  • DRAM dynamic random access memory
  • CMOS complementary metal oxide semi-conductor
  • a high- ⁇ dielectric film-forming lattice is provided.
  • the lattice which is an array of points repeating periodically in three dimensions, is comprised of hafnium oxide, titanium oxide, or mixtures thereof; and the lattice contains cerium atoms. The atoms are arranged upon the points of the lattice. The points form unit cells that fill the space of the lattice.
  • the cerium may also have an effect on the polarizability of the unit cell, i.e. the relative tendency of a charge distribution, like the electron cloud of an atom or molecule, to be distorted from its normal shape by an external electric field, which may be caused by the presence of a nearby ion or dipole.
  • this polarizability is enhanced which may impact the dielectric constant value beneficially by increasing or maintaining the dielectric constant longer.
  • Polarizability of the unit cell coupled with stabilization of the highest dielectric constant phase of each metal oxide may ensure that the maximum dielectric constant value can be obtained from the particular material system in use.
  • cerium atoms for the lattice are provided from at least one cerium precursor corresponding in structure to Formula I.
  • the cerium may be substitutional on the Group IV atomic sites or located interstitially, as interstitial inclusions.
  • the lattice is capable of forming a high- ⁇ dielectric film by a vapor deposition process, such as CVD or ALD.
  • the film formed by the lattice has a thickness from about 0.2 nm to about 500 nm; and contains from about 0.5 to about 35 atomic metal % cerium.
  • the metal oxide or mixed metal oxide film contains from about 5 to about 20 atomic metal % cerium. In a further particular embodiment, the metal oxide or mixed metal oxide film contains from about 8 to about 12 atomic metal % cerium.
  • the film formed by the lattice has a relative permittivity of about 20 to about 100, particularly from about 40 to about 70. Further, the film formed is capable of maintaining a relative permittivity of about 20 to about 100 at frequencies of about IKHz to about IGHz.

Abstract

Methods are provided to form and stabilize high-κ dielectric films by vapor deposition processes using metal-source precursors and cerium-based precursors according to Formula I: Ce(L)x (Formula I) wherin L is a cyclopentadienyl ring optionally substituted with one or more substituents independently selected from the group consisting of alkyl, alkoxy and NR1R2; or L is alkoxy; R1 and R2 are independently hydrogen or alkyl; and x is 3 or 4. Further provided are methods of improving high-κ gate property of semiconductor devices by using cerium precursors according to Formula I. High-κ dielectric film-forming lattices are also provided comprising cerium precursors according to Formula I.

Description

HIGH-K DIELECTRIC FILMS AND METHODS OF PRODUCING USING
CERIUM-BASED PRECURSORS
CROSS-REFRENCE TO RELATED APPLICATIONS
[0001] This patent claims the benefit of U.S. provisional application Serial No. 61/055,620, filed on 23 May 2008, the disclosure of which is incorporated herein by reference in its entirety. Disclosure of copending U.S. provisional application Serial No. 61/055,646, filed on 23 May 2008; copending U.S. provisional application Serial No. 61/055,594, filed on 23 May 2008; copending U.S. provisional application Serial No. 61/105,594, filed on 15 October 2008; and copending U.S. provisional application Serial No. 61/055,695, filed on 23 May 2008, are each incorporated herein by reference in their entirety without admission that such disclosures constitute prior art to the present invention.
FIELD OF THE INVENTION
[0002] The present invention relates to methods of forming high-κ dielectric thin metallic films, improving such films, and a lattice capable of forming such films.
BACKGROUND OF THE INVENTION
[0003] Various organometallic precursors are used to form high-κ dielectric thin metal films for use in the semiconductor industry. Various deposition processes are used to form the metal films, such as chemical vapor deposition ("CVD") or atomic layer deposition ("ALD"), also known as atomic layer epitaxy.
[0004] CVD is a chemical process whereby precursors are deposited on a substrate to form a solid thin film. In a typical CVD process, the precursors are passed over a substrate (wafer) within a low pressure or ambient pressure reaction chamber. The precursors react and/or decompose on the substrate surface creating a thin film of deposited material. Volatile by-products are removed by gas flow through the reaction chamber. The deposited film thickness can be difficult to control because it depends on coordination of many parameters such as temperature, pressure, gas flow volumes and uniformity, chemical depletion effects and time.
[0005] ALD is a chemical process which separates the precursors during the reaction. The first precursor is passed over the substrate producing a monolayer on the substrate. Any excess unreacted precursor is pumped out of the reaction chamber. A second precursor is then passed over the substrate and reacts with the first precursor, forming a second monolayer of film over the first-formed film on the substrate surface. This cycle is repeated to create a film of desired thickness. ALD film growth is self-limited and based on surface reactions, creating uniform depositions that can be controlled at the nanometer- thickness scale.
[0006] Yashima M., et. al. report zirconia-ceria solid solutions and lattice in an abstract presented at the Fall Meeting of the Ceramic Society of Japan, Kanazawa, Japan,
September 26-28 1990 (Paper No. 6-3A07), and at the 108th Annual Meeting of the Japan
Institute of Metals, Tokyo, Japan, April 2-4, 1991 (Paper No. 508).
[0007] Scott, H. G. reports metastable and equilibrium phase relationships in zirconia- yttria system. ["Phase Relationships in the zirconia-yttria system," J. Mat. Science.
1975. 10:1527-1535].
[0008] International Publication No. WO 02/27063 reports vapor deposition processes using metal oxides, silicates and phosphates, and silicon dioxide.
[0009] Zirconia, hafnia and TiO2 have been used to create dielectric films, generally to replace silicon dioxide gates for use in the semiconductor industry. Replacing silicon dioxide with a high-κ dielectric material allows increased gate capacitance without concomitant leakage effects.
[0010] Therefore, methods are needed to create and improve high-κ dielectric films by either increasing the dielectric constant, or stabilizing the film to maintain a high dielectric constant, or both.
SUMMARY OF THE INVENTION
[0011] There is now provided a method to form a high-κ dielectric film by a vapor deposition process. The method comprises delivering at least one metal-source precursor and at least one cerium precursor to a substrate, wherein the at least one cerium precursor corresponds in structure to Formula I:
Ce(L)x (Formula I)
wherein: L is a cyclopentadienyl ring optionally substituted with one or more substituents selected from the group consisting of alkyl, alkoxy and NRiR2; or L is alkoxy;
Ri and R2 are independently hydrogen or alkyl; and x is 3 or 4.
[0012] There is further provided a method to improve high-κ gate property of a semiconductor device. The method comprises using at least one cerium precursor to form a high-κ dielectric film for use in the semiconductor device, wherein the at least one cerium precursor corresponds in structure to Formula I.
[0013] There is further provided a method to stabilize a high-κ dielectric material.
The method comprises adding at least one cerium precursor to the high-κ dielectric material wherein the at least one cerium precursor corresponds in structure to Formula I.
[0014] There is further provided a high-κ dielectric film-forming lattice, wherein the lattice is comprised of hafnium oxide, titanium oxide or mixtures thereof and the lattice contains cerium atoms.
[0015] Other embodiments, including particular aspects of the embodiments summarized above, will be evident from the detailed description that follows.
DETAILED DESCRIPTION OF THE INVENTION
[0016] In various aspects of the invention, methods are provided that utilize cerium (III) and/or cerium (IV) precursors as dopants to form high-κ dielectric thin films. The methods of the invention are used to create or grow thin films with an improved high-κ gate property, and thus are able to maintain high dielectric constants. In other aspects of the invention a lattice is provided capable of forming a high-κ gate film. [0017] As used herein, the term "high-κ dielectric" refers to a material, such as a metal-containing film, with a higher dielectric constant (K) when compared to silicon dioxide (which has a dielectric constant of about 3.7). Typically, a high-κ dielectric film is used in semiconductor manufacturing processes to replace the silicon dioxide gate dielectric. A high-κ dielectric film may be referred to as having a "high-κ gate property" when the dielectric film is used as a gate material and has at least a higher dielectric constant than silicon dioxide.
[0018] As used herein, the term "relative permittivity" is synonymous with dielectric constant (K). [0019] As used herein, the term "vapor deposition process" is used to refer to any type of vapor deposition technique such as CVD or ALD. In various embodiments of the invention, CVD may take the form of liquid injection CVD. In other embodiments, ALD may be either photo-assisted ALD or liquid injection ALD.
[0020] As used herein, the term "precursor" refers to an organometallic molecule, complex and/or compound which is deposited or delivered to a substrate to form a thin film by a vapor deposition process such as CVD or ALD.
[0021] As used herein, the term "alkyl" refers to a saturated hydrocarbon chain of 1 to 10 carbon atoms in length, such as, but not limited to, methyl, ethyl, propyl and butyl. The alkyl group may be straight-chain or branched-chain. For example, as used herein, propyl encompasses both w-propyl and /so-propyl; butyl encompasses w-butyl, sec-butyl, zso-butyl and tert-butyl.
[0022] As used herein, the term "alkoxy" (alone or in combination with another term(s)) refers to a substituent, i.e., -O-alkyl. Examples of such a substituent include methoxy (-0-CH3), ethoxy, etc. The alkyl portion may be straight-chain or branched- chain. For example, as used herein, propoxy encompasses both w-propoxy and iso- propoxy; butoxy encompasses w-butoxy, zso-butoxy, sec-butoxy, and tert-butoxy. [0023] As used herein, the term "cyclopentadienyl" or "Cp" (C5H5) refers to a 5- membered carbon ring which is bound to a transition metal. As used herein, all five carbon atoms of the Cp ligand are bound to the metal center in η5-coordination by π bonding.
[0024] In a first embodiment, a method to form a high-κ dielectric film by a vapor deposition process is provided. The method comprises delivering at least one metal- source precursor and at least one cerium precursor to a substrate, wherein the at least one cerium precursor corresponds in structure to Formula I:
Ce(L)x (Formula I) wherein:
L is a cyclopentadienyl ring optionally substituted with one or more substituents selected from the group consisting of alkyl, alkoxy and NRiR2; or L is alkoxy; Ri and R2 are independently hydrogen or alkyl; and x is 3 or 4.
[0025] In one embodiment, L is a cyclopentadienyl ring optionally substituted with one or more substituents such as alkyl, alkoxy and NRiR2. In a particular embodiment, the cyclopentadienyl ring is substituted with one or more substituents such as alkyl, alkoxy and NRiR2. In a further particular embodiment, L is a cyclopentadienyl ring and x is 3, therefore in this embodiment there are three cyclopentadienyl rings attached to cerium.
[0026] In another embodiment, L is alkoxy group such as methoxy, ethoxy, propoxy, butoxy or pentoxy. In a particular embodiment, L is alkoxy and x is 4, therefore in this embodiment there are four alkoxy groups attached to cerium.
[0027] Examples of the at least one cerium precursor include, without limitation:
Figure imgf000006_0001
[0028] Any metal-source precursor suitable for forming a film may be used according to the invention. In a particular embodiment, the at least one metal-source precursor is compatible with the at least one cerium precursor. For example, without limitation, the at least one metal- source precursor may be compatible with the at least one cerium precursor for purposes of depositing a metal oxide film with the composition CexMi_xOy where M is either Hf, Zr or Ti; x has a value between about zero and about 0.5; and y has a value less than about 2.
[0029] Examples of the at least one metal-source precursor include, without limitation: a metal amide, such as Hafnium dimethylamide, Zirconium dimethylamide, Titanium dimethylamide, Hafnium ethylmethylamide, Zirconium ethylmethylamide, Titanium ethylmethylamide, Hafnium diethylamide, Zirconium diethylamide and Titanium diethylamide; a metal alkoxide, such as Hafnium t-butoxide, Zirconium t-butoxide, Titanium t-butoxide, Hafnium i-propoxide, Zirconium i-propoxide, Titanium i-propoxide, Hafnium bis t-butoxy bis 2-methyl-2-methoxy propoxide, Zirconium bis t-butoxy bis 2-methyl-2-methoxy propoxide, Titanium bis t-butoxy bis 2-methyl-2- methoxy propoxide, Zirconium bis i-propoxy bis 2-methyl-2-methoxy propoxide, Titanium bis i-propoxy bis 2-methyl-2-methoxy propoxide, Hafnium 2-methyl-2- methoxy propoxide, Zirconium 2-methyl-2-methoxy propoxide and Titanium 2- methyl-2-methoxy propoxide; a metal β-diketonate, such as Hafnium 2,2,6,6-tetramethyl-3,5-heptanedionate, Zirconium 2,2,6, 6-tetramethyl-3,5-heptanedionate, Titanium 2,2,6,6-tetramethyl- 3,5-heptanedionate, Zirconium bis i-propoxy bis 2,2,6,6-tetramethyl-3,5- heptanedionate and Titanium bis i-propoxy 2,2,6,6-tetramethyl-3,5- heptanedionate; a metal cyclopentadienyl, such as bis methylcyclopentadienyl Hafnium dimethyl, bis methylcyclopentadienyl Zirconium dimethyl, bis methylcyclopentadienyl Hafnium methyl methoxide, bis methylcyclopentadienyl Zirconium methyl methoxide, methylcyclopentadienyl Hafnium tris dimethylamide, methylcyclopentadienyl Zirconium tris dimethylamide and methylcyclopentadienyl Titanium tris dimethylamide.
[0030] Therefore, in one embodiment, the high-κ dielectric film formed by a method of the invention may comprise:
(1) hafnium oxide and cerium,
(2) zirconium oxide and cerium,
(3) titanium oxide and cerium, or
(4) mixtures of hafnium, zirconium and/or titanium oxide and cerium.
[0031] In a particular embodiment, at least one cerium precursor is used in a vapor deposition process with at least one hafnium precursor to create a cerium-doped hafnium oxide film. [0032] In another particular embodiment, at least one cerium precursor is used in a vapor deposition process with at least one zirconium precursor to create a cerium-doped zirconium oxide film.
[0033] In another particular embodiment, at least one cerium precursor is used in a vapor deposition process with at least one titanium precursor to create a cerium-doped titanium oxide film.
[0034] In another particular embodiment, at least one cerium precursor is used in a vapor deposition process with at least one hafnium precursor, zirconium precursor and/or titanium precursor to create a cerium doped "mixed" metal oxide film. Therefore, a "mixed" metal oxide film, as used herein, refers to a metal oxide film comprising cerium and one or more of the following: hafnium oxide, zirconium oxide and titanium oxide. [0035] In one embodiment, the method of the invention creates either hafnium oxide, zirconium oxide, titanium oxide or a mixed metal oxide dielectric film that contains from about 0.5 to about 35 atomic metal % cerium. In a particular embodiment the metal oxide or mixed metal oxide film contains from about 5 to about 20 atomic metal % cerium. In a further particular embodiment, the metal oxide or mixed metal oxide film contains from about 8 to about 12 atomic metal % cerium.
[0036] In one embodiment, the at least one metal source precursor and/or the at least one cerium precursor may be dissolved in an appropriate hydrocarbon or amine solvent. Appropriate hydrocarbon solvents include, but are not limited to aliphatic hydrocarbons, such as hexane, heptane and nonane; aromatic hydrocarbons, such as toluene and xylene; aliphatic and cyclic ethers, such as diglyme, triglyme and tetraglyme. Examples of appropriate amine solvents include, without limitation, octylamine and N5N- dimethyldodecylamine. For example, a precursor may be dissolved in toluene to yield a 0.05 to IM solution.
[0037] In a particular embodiment, the at least one cerium precursor is dissolved in an organic solvent, such as toluene, heptane, octane, nonane or tetrahydrofuran (THF). [0038] The cerium-doped films of the invention can be formed by chemical vapor deposition. In a particular embodiment, the chemical vapor deposition is liquid injection chemical vapor deposition.
[0039] Alternatively, the cerium-doped films of the invention can be formed by atomic layer deposition. In a particular embodiment, the atomic layer deposition is photo-assisted atomic layer deposition. And in another particular embodiment, the atomic layer deposition is liquid injection atomic layer deposition.
[0040] In the methods of the invention, each precursor is deposited and/or delivered onto a substrate in pulses alternating with pulses of an oxygen source. Any suitable oxygen source may be used, for example, H2O, O2 or ozone.
[0041] In a particular embodiment, each precursor is deposited onto a substrate in pulses with a continuous supply of the oxygen source such as H2O, O2 or ozone.
[0042] In one embodiment of the invention, the cerium-doped high-κ dielectric film has a relative permittivity of about 20 to about 100, particularly from about 40 to about
70. Further, the high-κ dielectric film is capable of maintaining a relative permittivity of about 20 to about 100 at frequencies of about IKHz to about IGHz.
[0043] A variety of substrates can be used in the methods of the present invention.
For example, the precursors according to Formula I may be deposited on substrates such as, but not limited to, silicon, silicon oxide, silicon nitride, tantalum, tantalum nitride, or copper.
[0044] In another embodiment of the invention, a method is provided to improve the high-κ gate property of a semiconductor device. The method comprises using at least one cerium precursor to form a high-κ dielectric film for use in the semiconductor device, wherein the at least one cerium precursor corresponds in structure to Formula I above.
[0045] Including at least one cerium precursor according to Formula I in a metal oxide film improves the high-κ gate property by either increasing the dielectric constant, allowing longer maintenance of a high dielectric constant or both, when compared to the particular metal oxide film without the at least one cerium precursor. This improves the high-κ gate property of the semiconductor device by increasing gate capacitance and improving permittivity for faster transistors and smaller devices.
[0046] For example, the dielectric constant can be increased about 20 to about 50 units by using at least one cerium precursor according to Formula I; or a high dielectric constant can be maintained at about IKHz to about IGHz, when compared to not using at least one cerium precursor according to Formula I.
[0047] In another embodiment of the invention, a method is provided to stabilize a high-κ dielectric material. The method comprises adding at least one cerium precursor to the high-κ dielectric material wherein the at least one cerium precursor corresponds in structure to Formula (I) above. The term "stabilize" refers generally to altering the high- K dielectric material such that the high-κ dielectric material is able to maintain a high dielectric constant at frequencies of about IKHz to about IGHz.
[0048] Therefore, in one embodiment of the invention, the cerium-doped high-κ dielectric film has a relative permittivity of about 20 to about 100, particularly from about 40 to about 70. Further, the high-κ dielectric film is capable of maintaining a relative permittivity of about 20 to about 100 at frequencies of about IKHz to about IGHz. [0049] The high-κ dielectric material may be any material wherein stabilization is needed to improve or maintain a high dielectric constant. For example, the high-κ dielectric material may be provided by a film composed of one or more of hafnium oxide, zirconium oxide, titanium oxide or a "mixed" metal oxide, for example, a hafnium, zirconium and/or titanium oxide mixture. Additionally, if three metals are present, then a "ternary" mixed metal oxide film can be stabilized.
[0050] Without being bound by theory, it is believed that doping hafnium, zirconium, or titanium with a +3-oxidation-state rare earth element causes or permits 'dielectric relaxation' in the film-forming materials or film thereby formed. High frequencies cause the dielectric constant (or relative permittivity) of the material to decrease, which is known as dielectric relaxation. It is hypothesized that dielectric relaxation occurs because substitution of hafnium, zirconium or titanium with the +3 element in the lattice causes an oxygen vacancy in order to maintain balanced charge. In order to improve the dielectric constant and/or maintain the dielectric constant at high frequencies, a hafnium oxide, zirconium oxide, titanium oxide or mixed oxide film can be created using a precursor as disclosed herein such that cerium (IV) is incorporated into the lattice. [0051] Thus in one embodiment of the invention, the high-κ dielectric material is stabilized by stabilizing the metastable phase of the metal used. For example, and without being bound by theory, pure zirconium oxide and hafnium oxide exhibit a stable monoclinic crystalline phase with dielectric constant typically in the range of about 18 to about 22. The metastable phases, such as tetragonal and cubic crystal structures of these materials, have high permittivities. Therefore, it is hypothesized that in order to stabilize the metastable phases, some of the Group IV metal may be replaced with one or more cerium precursors of Formula I which can adopt a +4 charge and may obviate the formation of charged oxygen ion vacancies.
[0052] Further, the use of cerium precursor(s) to stabilize different phases also has implications for radiation hardness, as the resistance to radiation can be increased which is very useful for space applications where resistance to degradation by various forms of radiation is key to device lifetimes and efficiencies. Therefore, these stabilized high-κ dielectric materials are useful in semiconductor devices and are useful for computer memory and logic applications, such as dynamic random access memory (DRAM) and complementary metal oxide semi-conductor (CMOS) circuitry.
[0053] In another embodiment of the invention, a high-κ dielectric film-forming lattice is provided. The lattice, which is an array of points repeating periodically in three dimensions, is comprised of hafnium oxide, titanium oxide, or mixtures thereof; and the lattice contains cerium atoms. The atoms are arranged upon the points of the lattice. The points form unit cells that fill the space of the lattice.
[0054] In addition to phase stabilization discussed above, without being bound by theory, the cerium may also have an effect on the polarizability of the unit cell, i.e. the relative tendency of a charge distribution, like the electron cloud of an atom or molecule, to be distorted from its normal shape by an external electric field, which may be caused by the presence of a nearby ion or dipole. With cerium present it is hypothesized that this polarizability is enhanced which may impact the dielectric constant value beneficially by increasing or maintaining the dielectric constant longer. Polarizability of the unit cell coupled with stabilization of the highest dielectric constant phase of each metal oxide may ensure that the maximum dielectric constant value can be obtained from the particular material system in use.
[0055] The cerium atoms for the lattice are provided from at least one cerium precursor corresponding in structure to Formula I.
[0056] The cerium may be substitutional on the Group IV atomic sites or located interstitially, as interstitial inclusions.
[0057] The lattice is capable of forming a high-κ dielectric film by a vapor deposition process, such as CVD or ALD.
[0058] In one embodiment, the film formed by the lattice has a thickness from about 0.2 nm to about 500 nm; and contains from about 0.5 to about 35 atomic metal % cerium.
In a particular embodiment the metal oxide or mixed metal oxide film contains from about 5 to about 20 atomic metal % cerium. In a further particular embodiment, the metal oxide or mixed metal oxide film contains from about 8 to about 12 atomic metal % cerium.
[0059] In another embodiment, the film formed by the lattice has a relative permittivity of about 20 to about 100, particularly from about 40 to about 70. Further, the film formed is capable of maintaining a relative permittivity of about 20 to about 100 at frequencies of about IKHz to about IGHz.
[0060] All patents and publications cited herein are incorporated by reference into this application in their entirety.
[0061] The words "comprise", "comprises", and "comprising" are to be interpreted inclusively rather than exclusively.

Claims

WHAT IS CLAIMED IS:
1. A method to form a high-κ dielectric film by a vapor deposition process, the method comprising delivering at least one metal-source precursor and at least one cerium precursor to a substrate, wherein the at least one cerium precursor corresponds in structure to Formula I:
Ce(L)x (Formula I)
wherein:
L is a cyclopentadienyl ring optionally substituted with one or more substituents independently selected from the group consisting of alkyl, alkoxy and NRiR2; or
L is alkoxy;
Ri and R2 are independently hydrogen or alkyl; and x is 3 or 4.
2. The method of Claim 1, wherein
L is a cyclopentadienyl ring optionally substituted with one or more substituents independently selected from the group consisting of alkyl, alkoxy and NRiR2.
3. The method of Claim 2, wherein the cyclopentadienyl ring is substituted with one or more substituents independently selected from the group consisting of alkyl, alkoxy and NRiR2; and x is 3.
4. The method of Claim 1, wherein
L is independently selected from the group consisting of methoxy, ethoxy, propoxy, butoxy and pentoxy; and x is 4.
5. The method of Claim 1, wherein the at least one cerium precursor is selected from the group consisting of t-butyl —
Figure imgf000014_0001
6. The method of Claim 1, wherein the high-κ dielectric film comprises hafnium oxide and cerium; or zirconium oxide and cerium; or titanium oxide and cerium; or mixtures of hafnium oxide, zirconium oxide and/or titanium oxide and cerium.
7. The method of Claim 6, wherein the hafnium oxide, zirconium oxide, titanium oxide or mixture thereof contains from about 0.5 to about 35 atomic metal % cerium.
8. The method of Claim 7, wherein the hafnium oxide, zirconium oxide, titanium oxide or mixture thereof contains from about 5 to about 20 atomic metal % cerium.
9. The method of Claim 7, wherein the hafnium oxide, zirconium oxide, titanium oxide or mixture thereof contains from about 8 to about 12 atomic metal % cerium.
10. The method of Claim 1, wherein the vapor deposition process is chemical vapor deposition.
11. The method of Claim 10, wherein the chemical vapor deposition is liquid injection chemical vapor deposition.
12. The method of Claim 1, wherein the vapor deposition process is atomic layer deposition.
13. The method of Claim 12, wherein the atomic layer deposition is photo-assisted atomic layer deposition.
14. The method of Claim 12, wherein the atomic layer deposition is liquid injection atomic layer deposition.
15. The method of Claim 1, wherein the at least one cerium precursor is dissolved in an organic solvent.
16. The method of Claim 15, wherein the organic solvent is selected from the group consisting of toluene, heptane, octane, nonane and tetrahrydrofuran.
17. The method of Claim 1, wherein each precursor is deposited onto the substrate in pulses alternating with pulses of an oxygen source.
18. The method of Claim 17, wherein the oxygen source is H2O, O2 or ozone.
19. The method of Claim 1, wherein each precursor is deposited onto the substrate in pulses with a continuous supply of the oxygen source.
20. The method of Claim 19, wherein the oxygen source is H2O, O2 or ozone.
21. The method of Claim 1, wherein the at least one metal-source precursor is compatible with the cerium precursor.
22. The method of Claim 1, wherein the at least one metal-source precursor is selected from the group consisting of a metal amide selected from the group consisting of Hafnium dimethylamide, Zirconium dimethylamide, Titanium dimethylamide, Hafnium ethylmethylamide, Zirconium ethylmethylamide, Titanium ethylmethylamide, Hafnium diethylamide, Zirconium diethylamide and Titanium diethylamide; a metal alkoxide selected from the group consisting of Hafnium t-butoxide, Zirconium t-butoxide, Titanium t-butoxide, Hafnium i-propoxide, Zirconium i- propoxide, Titanium i-propoxide, Hafnium bis t-butoxy bis 2-methyl-2-methoxy propoxide, Zirconium bis t-butoxy bis 2-methyl-2-methoxy propoxide, Titanium bis t-butoxy bis 2-methyl-2-methoxy propoxide, Zirconium bis i-propoxy bis 2- methyl-2-methoxy propoxide, Titanium bis i-propoxy bis 2-methyl-2-methoxy propoxide, Hafnium 2-methyl-2-methoxy propoxide, Zirconium 2-methyl-2- methoxy propoxide and Titanium 2-methyl-2-methoxy propoxide; a metal β-diketonate selected from the group consisting of Hafnium 2,2,6,6- tetramethyl-3,5-heptanedionate, Zirconium 2,2,6, 6-tetramethyl-3,5- heptanedionate, Titanium 2,2,6, 6-tetramethyl-3,5-heptanedionate, Zirconium bis i-propoxy bis 2,2,6,6-tetramethyl-3,5-heptanedionate and Titanium bis i-propoxy 2,2,6,6-tetramethyl-3,5-heptanedionate; a metal cyclopentadienyl selected from the group consisting of bis methylcyclopentadienyl Hafnium dimethyl, bis methylcyclopentadienyl Zirconium dimethyl, bis methylcyclopentadienyl Hafnium methyl methoxide, bis methylcyclopentadienyl Zirconium methyl methoxide, methylcyclopentadienyl Hafnium tris dimethylamide, methylcyclopentadienyl Zirconium tris dimethylamide and methylcyclopentadienyl Titanium tris dimethylamide.
23. The method of Claim 1, wherein the high-κ dielectric film has a relative permittivity of about 20 to about 100.
24. The method of Claim 1, wherein the high-κ dielectric film can maintain a relative permittivity of about 20 to about 100 at frequencies of about IKHz to about IGHz.
25. The method of Claim 1, wherein the high-κ dielectric film is used for memory and logic applications in silicon chips.
26. A method to improve high-κ gate property of a semiconductor device, the method comprising using at least one cerium precursor to form a high-κ dielectric film for use in the semiconductor device, wherein the at least one cerium precursor corresponds in structure to Formula I:
Ce(L)x (Formula I)
wherein:
L is a cyclopentadienyl ring optionally substituted with one or more substituents selected from the group consisting of alkyl, alkoxy and NRiR2; or L is alkoxy;
Ri and R2 are independently hydrogen or alkyl; and x is 3 or 4.
27. The method of Claim 26, wherein
L is a cyclopentadienyl ring optionally substituted with one or more substituents independently selected from the group consisting of alkyl, alkoxy and NRiR2.
28. The method of Claim 26, wherein the cyclopentadienyl ring is substituted with one or more substituents independently selected from the group consisting of alkyl, alkoxy and NRiR2; and x is 3.
29. The method of Claim 26, wherein
L is independently selected from the group consisting of methoxy, ethoxy, propoxy, butoxy and pentoxy; and x is 4.
30. The method of Claim 26, wherein the high-κ dielectric film comprises hafnium oxide containing cerium; zirconium oxide containing cerium; titanium oxide containing cerium; or mixtures of hafnium oxide, zirconium oxide and/or titanium oxide containing cerium.
31. The method of Claim 26, wherein the high-κ dielectric film has a relative permittivity of about 20 to about 100.
32. The method of Claim 26, wherein the high-κ dielectric film can maintain a relative permittivity of about 20 to about 100 at frequencies of about IKHz to about IGHz.
33. The method of Claim 26, wherein the high-κ dielectric film is formed by chemical vapor deposition or atomic layer deposition.
34. A method to stabilize a high-κ dielectric material, the method comprising adding at least one cerium precursor to the high-κ dielectric material wherein the at least one cerium precursor corresponds in structure to Formula I:
Ce(L)x (Formula I)
wherein:
L is a cyclopentadienyl ring optionally substituted with one or more substituents independently selected from the group consisting of alkyl, alkoxy and NRiR2; or
L is alkoxy;
Ri and R2 are independently hydrogen or alkyl; and x is 3 or 4.
35. The method of Claim 34, wherein L is a cyclopentadienyl ring optionally substituted with one or more substituents independently selected from the group consisting of alkyl, alkoxy and NRiR2.
36. The method of Claim 34, wherein the cyclopentadienyl ring is substituted with one or more substituents independently selected from the group consisting of alkyl, alkoxy and NRiR2; and x is 3.
37. The method of Claim 34, wherein
L is independently selected from the group consisting of methoxy, ethoxy, propoxy, butoxy and pentoxy; and x is 4.
38. The method of Claim 34, wherein the high-κ dielectric material is hafnium oxide, zirconium oxide, titanium oxide or a mixture of hafnium oxide, zirconium oxide and/or titanium oxide.
39. The method of Claim 38, wherein to stabilize the high-κ dielectric material a hafnium, zirconium or titanium oxide metastable phase is maintained.
40. The method of Claim 38, wherein stabilization of a hafnium oxide, zirconium oxide or titanium oxide results in a relative permittivity of about 20 to about 100.
41. The method of Claim 38, wherein stabilization of a hafnium oxide, zirconium oxide or titanium oxide results in a relative permittivity of about 25 to about 100 at frequencies of about IKHz to about IGHz.
42. The method of Claim 34, wherein the stabilized high-κ dielectric material is used in a semiconductor device.
43. A high-κ dielectric film- forming lattice, wherein the lattice is comprised of hafnium oxide, titanium oxide or mixture thereof and the lattice contains cerium atoms.
44. The high-κ dielectric film-forming lattice of Claim 43, wherein the cerium is substitutionally part of the lattice or the cerium is part of the lattice as interstitial inclusions.
45. The high-κ dielectric film-forming lattice of Claim 43, wherein the cerium atoms are provided from at least one cerium precursor corresponding in structure to Formula I:
Ce(L)x (Formula I)
wherein:
L is a cyclopentadienyl ring optionally substituted with one or more substituents independently selected from the group consisting of alkyl, alkoxy and NRiR2; or
L is alkoxy;
Ri and R2 are independently hydrogen or alkyl; and x is 3 or 4.
46. The high -K dielectric film- forming lattice of Claim 45, wherein
L is a cyclopentadienyl ring optionally substituted with one or more substituents independently selected from the group consisting of alkyl, alkoxy and NRiR2.
47. The high -K dielectric film- forming lattice of Claim 45, wherein the cyclopentadienyl ring is substituted with one or more substituents independently selected from the group consisting of alkyl, alkoxy and NRiR2; and x is 3.
48. The high -K dielectric film- forming lattice of Claim 45, wherein
L is independently selected from the group consisting of methoxy, ethoxy, propoxy, butoxy and pentoxy; and x is 4.
49. The high -K dielectric film- forming lattice of Claim 43, wherein the film formed has a thickness from about 0.2nm to about 500nm.
50. The high-κ dielectric film forming lattice of Claim 43, wherein the film formed has a relative permittivity of about 20 to about 100.
51. The high-κ dielectric film forming lattice of Claim 43, wherein the film formed has a relative permittivity of about 20 to about 100 at frequencies of about IKHz to about IGHz.
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US8568530B2 (en) 2005-11-16 2013-10-29 Sigma-Aldrich Co. Llc Use of cyclopentadienyl type hafnium and zirconium precursors in atomic layer deposition
US8476467B2 (en) 2007-07-24 2013-07-02 Sigma-Aldrich Co. Llc Organometallic precursors for use in chemical phase deposition processes
US8481121B2 (en) 2007-07-24 2013-07-09 Sigma-Aldrich Co., Llc Methods of forming thin metal-containing films by chemical phase deposition
USRE45124E1 (en) 2007-09-14 2014-09-09 Sigma-Aldrich Co. Llc Methods of atomic layer deposition using titanium-based precursors
US8613975B2 (en) 2008-05-23 2013-12-24 Sigma-Aldrich Co. Llc Methods of producing high-K dielectric films using cerium-based precursors
US9028917B2 (en) 2009-08-07 2015-05-12 Sigma-Aldrich Co. Llc High molecular weight alkyl-allyl cobalttricarbonyl complexes and use thereof for preparing dielectric thin films
US9802220B2 (en) 2010-08-27 2017-10-31 Merck Patent Gmbh Molybdenum (IV) amide precursors and use thereof in atomic layer deposition
US8927748B2 (en) 2011-08-12 2015-01-06 Sigma-Aldrich Co. Llc Alkyl-substituted allyl carbonyl metal complexes and use thereof for preparing dielectric thin films
US9175023B2 (en) 2012-01-26 2015-11-03 Sigma-Aldrich Co. Llc Molybdenum allyl complexes and use thereof in thin film deposition
CN111834230A (en) * 2020-06-22 2020-10-27 华南师范大学 Preparation method of cerium-doped zirconium oxide film and application of cerium-doped zirconium oxide film in preparation of transistor
CN111834230B (en) * 2020-06-22 2023-01-13 华南师范大学 Preparation method of cerium-doped zirconium oxide film and application of cerium-doped zirconium oxide film in preparation of transistor

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