DUAL METAL GATE STRUCTURES AND METHODS
First Claim
1. A semiconductor structure comprising a first gate stack and a second gate stack located on a semiconductor substrate, wherein said first gate stack comprises a first gate dielectric vertically abutting said semiconductor substrate, a first metal portion vertically abutting said first gate dielectric and comprising a first metallic material, and a second metal portion vertically abutting said first metal portion and comprising a second metallic material which is different from said first metallic material, and wherein said second gate stack comprises a second gate dielectric vertically abutting said semiconductor substrate and a third metal portion vertically abutting said second gate dielectric and comprising said second metallic material.
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Accused Products
Abstract
Two dummy gate structures containing disposable material portions and metal portions, source and drain regions, and metal semiconductor alloy regions are formed on a semiconductor substrate. A dielectric material layer is deposited and planarized so that top surfaces of the two remaining dummy gate structures are substantially coplanar. A disposable material portion and a metal portion are removed from one dummy gate structure, while the other dummy gate structure is protected. Subsequently, another disposable material portion is removed from the other dummy gate structure. A second metal layer comprising a second metal is deposited and planarized to form two gate electrodes. One gate electrode has a gate dielectric abutting the first metal, while the other electrode has a gate electrode abutting the second metal. Both gate electrodes have substantially the same height since the two top surfaces of the gate electrodes are formed by the same planarization process.
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Citations
20 Claims
- 1. A semiconductor structure comprising a first gate stack and a second gate stack located on a semiconductor substrate, wherein said first gate stack comprises a first gate dielectric vertically abutting said semiconductor substrate, a first metal portion vertically abutting said first gate dielectric and comprising a first metallic material, and a second metal portion vertically abutting said first metal portion and comprising a second metallic material which is different from said first metallic material, and wherein said second gate stack comprises a second gate dielectric vertically abutting said semiconductor substrate and a third metal portion vertically abutting said second gate dielectric and comprising said second metallic material.
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9. The semiconductor structure of claim 9, wherein said semiconductor material is silicon, and wherein said second metallic material comprises one of Zr, W, Ta, Hf, Ti, Al, a metal carbide, a transition metal aluminide, and a combination thereof.
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13. A method of forming a semiconductor structure comprising:
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forming a first dummy gate structure and a second dummy gate structure on a semiconductor substrate, wherein said first dummy gate structure includes a stack of a first gate dielectric, a first metal portion comprising a first metallic material, and a first disposable material portion from bottom to top in that order and said second dummy gate structure includes a stack of a second gate dielectric, a second metal portion comprising said first metallic material, and a second disposable material portion from bottom to top in that order; removing said second disposable material portion and said second metal portion, while preserving said second gate dielectric and said first disposable material portion; removing said first disposable material portion, while preserving said first metal portion; and forming a third metal portion directly on said second gate dielectric and a fourth metal portion directly on said first metal portion, wherein said third metal portion and said fourth metal portion comprise a second metallic material. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification