Integrated circuit metal gate structure and method of fabrication
First Claim
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1. A method of fabricating a semiconductor device, comprising:
- providing a semiconductor substrate;
forming an interface layer on the semiconductor substrate;
forming a first gate dielectric layer on the interface layer;
forming a first layer on the first gate dielectric layer, wherein the first layer is a metal layer;
oxidizing the first layer to form a metal oxide layer, wherein the oxidizing the metal layer includes gettering oxygen from the interface layer;
forming a second layer including a metal oxide, wherein the forming the second layer includes depositing a layer of at least one of TaC, TaCO, TaCNO and oxidizing the deposited layer using at least one of an anneal and a plasma process, and further includes diffusing oxygen from the second layer to the first gate dielectric layer; and
forming a third layer on the second layer;
wherein the third layer includes metal.
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Abstract
A method of forming a gate structure is provided. The method includes providing a metal layer in the gate structure, the metal layer includes an oxygen-gettering composition. The metal layer getters oxygen from the interface layer, which may decrease the thickness of the interface layer. The gettered oxygen converts the metal layer to a metal oxide, which may act as a gate dielectric for the gate structure. A multi-layer metal gate structure is also provided including a oxygen-gettering metal layer, an oxygen-containing metal layer, and a polysilicon interface metal layer overlying a high-k gate dielectric.
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Citations
15 Claims
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1. A method of fabricating a semiconductor device, comprising:
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providing a semiconductor substrate; forming an interface layer on the semiconductor substrate; forming a first gate dielectric layer on the interface layer; forming a first layer on the first gate dielectric layer, wherein the first layer is a metal layer; oxidizing the first layer to form a metal oxide layer, wherein the oxidizing the metal layer includes gettering oxygen from the interface layer; forming a second layer including a metal oxide, wherein the forming the second layer includes depositing a layer of at least one of TaC, TaCO, TaCNO and oxidizing the deposited layer using at least one of an anneal and a plasma process, and further includes diffusing oxygen from the second layer to the first gate dielectric layer; and forming a third layer on the second layer;
wherein the third layer includes metal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 14)
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10. A method of semiconductor device fabrication, comprising:
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providing a semiconductor substrate; forming an interfacial layer on the semiconductor substrate; depositing a high-k dielectric layer on the interfacial layer; forming a multi-layer metal gate on the high-k dielectric layer, wherein the multi-layer metal gate includes; forming a first layer, wherein the first layer includes an oxygen gettering composition selected from the group consisting of TaC, TaCO, TaCNO, TaN, TiON, and MoON; gettering oxygen from the interfacial layer using the first layer; forming a second layer in-situ with the forming the first layer, wherein the second layer has a composition which includes a metal and oxygen; oxidizing the second layer to form a metal oxide layer; diffusing oxygen from the oxidized second layer to the high-k dielectric layer; and forming a third metal layer. - View Dependent Claims (11, 12, 13, 15)
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Specification