Low temperature method of forming a gate stack with a high k layer deposited over an interfacial oxide layer
AssigneeASM International N.V.
InventorsSuvi Haukka, Eric Shero, Christophe Pomarede, Jan Willem Hub Maes, Marko Tuominen
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Abstract
The present invention relates to methods for forming dielectric layers on a substrate, such as in an integrated circuit. In one aspect of the invention, a thin interfacial layer is formed. The interfacial layer is preferably an oxide layer and a high-k material is preferably deposited on the interfacial layer by a process that does not cause substantial further growth of the interfacial layer. For example, water vapor may be used as an oxidant source during high-k deposition at less than or equal to about 300° C.
Claims38
A process for forming a gate dielectric on a semiconductor substrate, the method comprising:
- growing an interfacial dielectric oxynitride layer from the substrate by thermal oxidation;
- and
- depositing a high-k layer over the interfacial dielectric layer by an atomic layer deposition (ALD) process under conditions such that the thickness of the interfacial dielectric layer increases by less than about 15 Å while depositing the high-k layer, wherein the ALD process comprises a plurality of cycles, each cycle comprising:
- contacting a substrate in a reaction chamber with a first reactant;
- removing the unreacted first reactant from the reaction chamber;
- contacting the substrate with water vapor;
- and
- removing the unreacted water vapor from the reaction chamber,
- and wherein water vapor is the only oxygen source used during deposition of the high-k layer.
A process for forming a compound dielectric layer on the surface of a substrate comprising forming an interfacial dielectric layer comprising nitrogen that is less than about 15 Å thick and depositing a high-k material directly on top of the interfacial dielectric layer by an atomic layer deposition (ALD) type process without growing the interfacial dielectric layer further, wherein the ALD process comprises sequentially and alternatingly exposing the substrate to a first reactant comprising a metal containing compound and water and wherein water is the only oxygen source chemical utilized during the deposition of the high-k layer.
A process for forming a compound dielectric layer on the surface of a substrate comprising forming an oxide layer less than about 15 Å thick and depositing a high-k material on top of the oxide layer by an atomic layer deposition (ALD) type process without growing the oxide layer further, wherein the atomic layer deposition type process comprises sequential surface reactions wherein the substrate is sequentially and alternatingly exposed to a first metal containing compound and a second oxidizing compound, and wherein the second oxidizing compound is a metal organic compound.
A process for forming a compound dielectric layer on the surface of a substrate comprising forming an oxide layer less than about 15 Å thick and depositing a high-k material on top of the oxide layer by an atomic layer deposition (ALD) type process without growing the oxide layer further, wherein the atomic layer deposition type process comprises sequential surface reactions wherein the substrate is sequentially and alternatingly exposed to a first metal containing compound and a second oxidizing compound, and wherein the first metal containing compound is a metal halide and the second oxidizing compound is a metal alkoxide.
A process for forming a compound dielectric layer on the surface of a substrate comprising forming an oxide layer less than about 15 Å thick and depositing a high-k material on top of the oxide layer by an atomic layer deposition (ALD) type process without growing the oxide layer further, wherein the atomic layer deposition type process comprises sequential surface reactions wherein the substrate is sequentially and alternatingly exposed to a first metal containing compound and a second oxidizing compound, and wherein the first metal containing compound and the second oxidizing compound are both metal alkoxides.
A process for forming a gate dielectric on a semiconductor substrate, the method comprising:
- growing an interfacial dielectric oxide layer from the substrate by thermal oxidation;
- and
- depositing a high-k layer over the interfacial dielectric layer by an atomic layer deposition (ALD) process under conditions such that the thickness of the interfacial dielectric layer increases by less than about 15 Å while depositing the high-k layer, wherein the high-k material is deposited by direct decomposition of a metal source compound.
A method of forming a dielectric layer on a silicon substrate comprising:
- growing a silicon oxynitride interface layer on the substrate, the interface layer having a thickness of less than about 15 Å;
- and
- depositing a high-k material on top of the interface layer,
- wherein depositing comprises maintaining the substrate at a temperature less than about 300° C. and supplying water vapor as an oxidizing agent, and wherein the interface layer grows by less than about 15 Å during deposition of the high-k material, and wherein water vapor is the only oxidizing agent supplied during deposition of the high-k material.
Dependencies are inferred from the claim text.