SIC power DMOSFET with self-aligned source contact
First Claim
Patent Images
1. A silicon carbide power MOSFET, comprising:
- a silicon carbide wafer having a substrate and a drift layer on said substrate, said drift layer having a plurality of source regions formed adjacent an upper surface thereof;
a plurality of polysilicon gates above said drift layer, said plurality of polysilicon gates including a first gate adjacent a first of said source regions, said first gate having a top surface, a lower surface and a sidewall, said sidewall overlying said first source region;
a first oxide layer between said first gate lower surface and said upper surface of said drift layer;
a second, thicker oxide layer over said top surface and sidewall of said first gate; and
a conformal layer of metal extending laterally across said first gate top surface and sidewall and said adjacent first source region.
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Accused Products
Abstract
An intermediate product in the fabrication of a MOSFET, including a silicon carbide wafer having a substrate and a drift layer on said substrate, said drift layer having a plurality of source regions formed adjacent an upper surface thereof; a first oxide layer on said upper surface of said drift layer; a plurality of polysilicon gates above said first oxide layer, said plurality of polysilicon gates including a first gate adjacent a first of said source regions; an oxide layer over said first source region of greater thickness than said first oxide layer; and, an oxide layer over said first gate of substantially greater thickness than said oxide layer over said first source region.
73 Citations
16 Claims
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1. A silicon carbide power MOSFET, comprising:
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a silicon carbide wafer having a substrate and a drift layer on said substrate, said drift layer having a plurality of source regions formed adjacent an upper surface thereof; a plurality of polysilicon gates above said drift layer, said plurality of polysilicon gates including a first gate adjacent a first of said source regions, said first gate having a top surface, a lower surface and a sidewall, said sidewall overlying said first source region; a first oxide layer between said first gate lower surface and said upper surface of said drift layer; a second, thicker oxide layer over said top surface and sidewall of said first gate; and a conformal layer of metal extending laterally across said first gate top surface and sidewall and said adjacent first source region.
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2. A silicon carbide MOSFET structure, comprising:
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a silicon carbide wafer having a substrate body having a source region formed adjacent an upper surface thereof; first and second oxide layers on said upper surface adjacent said source region; a polysilicon gate above each of said first and second oxide layers; a gate oxide layer, thicker than said first and second oxide layers beneath said gates, over each of said gates and the sides thereof; and a metal or oxide layer over said source region, extending between adjacent gate oxide layers. - View Dependent Claims (3)
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4. A silicon carbide MOSFET structure, comprising:
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a silicon carbide wafer having a substrate body having a source region formed adjacent an upper surface thereof; first and second oxide layers on said upper surface adjacent said source region; a polysilicon gate above each of said first and second oxide layers; a gate oxide layer, thicker than said first and second oxide layers beneath said gates, over each of said gates and the sides thereof; a metal or oxide layer over said source region, extending between adjacent gate oxide layers; and wherein said layer over said source region is an oxide layer of greater thickness than said first and second oxide layers and substantially less thickness than said gate oxide layers.
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5. A silicon carbide MOSFET structure, comprising:
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a silicon carbide wafer having a substrate body having a source region formed adjacent an upper surface thereof; first and second oxide layers on said upper surface adjacent said source region; a polysilicon gate above each of said first and second oxide layers; a gate oxide layer, thicker than said first and second oxide layers beneath said gates, over each of said gates and the sides thereof; a metal or oxide layer over said source region, extending between adjacent gate oxide layers; and wherein said MOSFET structure has a first state in which said layer over said source region is an oxide layer of greater thickness than said first and second oxide layers and substantially less thickness than said gate oxide layers, and a second state in which said layer over said source region is a conformal layer of metal extending laterally across said gates and said source region.
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6. A MOSFET structure, comprising:
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a silicon carbide wafer having a substrate body with an upper surface, said substrate body having at least one source region formed adjacent said upper surface; a substrate surface oxidation layer on said upper surface of said substrate body and adjacent said source region; at least two polysilicon gates above said substrate surface oxidation layer, said gates each having a top, a bottom and sides, wherein a first source region of said at least one source region is juxtaposed between first and second adjacent gates of said at least two polysilicon gates; a gate oxide layer, thicker than said substrate surface oxidation layer, over said tops and sides of each of said gates; and a material layer over said first source region and between said gate oxide layers on said sides of said gates, said material layer comprising one of an oxide and a metal contact. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification