Method of forming silicided gate structure
First Claim
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1. A method of forming a silicided gate of a field effect transistor on a substrate having active regions, comprising the steps of:
- (a) forming a shielding layer over said substrate, including over said active regions, said shielding layer having an opening therein to expose a surface of said gate electrode;
(b) fully siliciding said gate electrode, wherein said shielding layer prevents formation of said silicide in said active regions during step (b);
(c) after step (b), depositing a metal over the active regions and said gate electrode; and
(d) annealing to cause the metal to react to form silicide in the active regions, wherein the thickness of said gate silicide is greater than the thickness of said silicide in said active regions.
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Abstract
A method of forming a silicided gate of a field effect transistor on a substrate having active regions is provided. The method includes the following steps: (a) forming a silicide in at least a first portion of a gate; (b) after step (a), depositing a metal over the active regions and said gate; and (c) annealing to cause the metal to react to form silicide in the active regions, wherein the thickness of said gate silicide is greater than the thickness of said silicide in said active regions.
74 Citations
19 Claims
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1. A method of forming a silicided gate of a field effect transistor on a substrate having active regions, comprising the steps of:
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(a) forming a shielding layer over said substrate, including over said active regions, said shielding layer having an opening therein to expose a surface of said gate electrode; (b) fully siliciding said gate electrode, wherein said shielding layer prevents formation of said silicide in said active regions during step (b); (c) after step (b), depositing a metal over the active regions and said gate electrode; and (d) annealing to cause the metal to react to form silicide in the active regions, wherein the thickness of said gate silicide is greater than the thickness of said silicide in said active regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of forming a silicided gate of a field effect transistor on a substrate having active regions, comprising the steps of:
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conformally depositing a shielding layer over the active regions and gate, wherein said gate comprises silicon, said gate having sidewall spacers formed adjacent thereto, said shielding layer being formed over said sidewall spacers; etching an opening in said shielding layer to expose a top surface of said gate; depositing a first metal layer over said substrate, including on said exposed surface of said gate; annealing to cause said first metal to react with said gate, wherein said gate is fully silicided, wherein said shielding layer prevents formation of said silicide in said active regions during said annealing step; removing unreacted portions of said first metal layer; removing remaining portions of said shielding layer; depositing a second metal over said substrate, including over said active regions and said gate; and annealing to cause said second metal to react with said active regions to form silicide therein, wherein the thickness of said gate silicide is greater than the thickness of said silicide in said active regions. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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Specification