SOI SUBSTRATE CONTACT WITH EXTENDED SILICIDE AREA
First Claim
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1. A method, comprising:
- (a) forming dielectric isolation in an upper silicon layer of a substrate, said substrate comprising a buried oxide layer between said upper silicon layer and a lower silicon layer, said dielectric isolation extending from a top surface of said upper silicon layer to said buried oxide layer, said dielectric isolation surrounding a contact region of said upper silicon layer;
(b) forming an opening extending through said contact region and through said buried oxide layer to said lower silicon layer, portions of said contact region remaining between said opening and said dielectric isolation;
(c) filling said opening with polysilicon to form a polysilicon region;
(d) implanting a dopant of a same dopant type as a dopant type of said lower silicon layer into said polysilicon region and remaining portions of said contact region; and
(e) forming a contiguous metal silicide layer in said remaining portions of said contact region and said polysilicon region, said metal silicide layer extending from a top surface of said polysilicon region into said polysilicon region and extending from a top surface of said remaining portions of said contact region into said remaining portions of said contact region.
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Abstract
A low resistance contact structure and method of making the structure. The structure includes a polysilicon contact through an upper silicon layer and buried oxide layer to a lower silicon layer of a silicon-on-insulation substrate. A region of the upper silicon layer surrounds the polysilicon contact and top surface of the polysilicon contact and surrounding region of upper silicon layer are metal silicided providing an extended contact area greater than the area of the top surface of polysilicon contact.
8 Citations
20 Claims
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1. A method, comprising:
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(a) forming dielectric isolation in an upper silicon layer of a substrate, said substrate comprising a buried oxide layer between said upper silicon layer and a lower silicon layer, said dielectric isolation extending from a top surface of said upper silicon layer to said buried oxide layer, said dielectric isolation surrounding a contact region of said upper silicon layer; (b) forming an opening extending through said contact region and through said buried oxide layer to said lower silicon layer, portions of said contact region remaining between said opening and said dielectric isolation; (c) filling said opening with polysilicon to form a polysilicon region; (d) implanting a dopant of a same dopant type as a dopant type of said lower silicon layer into said polysilicon region and remaining portions of said contact region; and (e) forming a contiguous metal silicide layer in said remaining portions of said contact region and said polysilicon region, said metal silicide layer extending from a top surface of said polysilicon region into said polysilicon region and extending from a top surface of said remaining portions of said contact region into said remaining portions of said contact region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 20)
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11. A method, comprising:
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(a) forming dielectric isolation in an upper silicon layer of a substrate, said substrate comprising a buried oxide layer between said upper silicon layer and a lower silicon layer, said dielectric isolation extending from a top surface of said upper silicon layer to said buried oxide layer, said dielectric isolation surrounding a contact region of said upper silicon layer and surrounding a device region of said upper silicon layer; (b) forming an opening extending through said contact region and through said buried oxide layer to said lower silicon layer, portions of said contact region remaining between said opening and said dielectric isolation; (c) filling said opening with polysilicon to form a polysilicon region; (d) forming a gate dielectric layer on top surfaces of said polysilicon region, remaining portions of said contact region and said device region; (e) forming a gate electrode on said gate dielectric layer; (f) implanting a dopant of a same dopant type as a dopant type of said lower silicon layer into said polysilicon region, remaining portions of said contact region and source/drain regions in said device region;
said source/drain regions on opposite sides of said gate electrode not covered by said gate electrode;(g) removing said gate dielectric layer from over said polysilicon region, remaining portions of said contact region and said source/drain regions; and (h) forming metal silicide layers in said remaining portions of said contact region, said polysilicon region and said source/drain regions, said metal silicide layers extending from respective top surfaces of said polysilicon region into said polysilicon region, of said remaining portions of said contact region into said remaining portions of said contact region and of said source/drain regions into said source/drain regions, said metal silicide layers in said remaining portions of said contact region and said polysilicon region being contiguous. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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Specification