Patent US5712503A successfully refreshed from Google Patents.
US5712503A
Expired / Lapsed
US
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Metal oxide semiconductor and method of making the same
Assignee: SK Hynix Inc
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Filing: 1995-08-10
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Granted: 1998-01-27
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Expires: 2015-08-10
Abstract
Abstract A metal oxide semiconductor transistor including a silicon substrate of a first conductivity type and having a central portion having a channel region which has a recessed surface. The substrate has another portion which has a flat surface. A thin gate oxide film is formed on the recessed surface and an oxide film, which is thicker than the gate oxide film, is formed on the flat surface. A gate is formed on the gate oxide film and has a flat upper surface and a convex lower surface. A thick cap oxide film is formed on the gate. Low concentration source and drain regions of a second conductivity type overlap completely with the gate and are formed adjacent to the channel region. High concentration source and drain regions of the second conductivity type are formed on the flat surface of the silicon substrate and adjacent to the low concentration source and drain regions. Impurity regions are either formed on the silicon substrate and enclose the low concentration source and drain regions, or are of the first conductivity type and positioned in the bulk and under the channel region.
Inventors
- 👤 Kyung Saeng Kim
- 👤 Jun Hee Lim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:39
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/021; H10D30/022; H10D30/0217; H10D30/0218; H10D30/60; H10D30/601; H10D30/605; H10D30/608; H10D62/00; H10D62/10; H10D62/17; H10D62/351; H10D62/357; H10D62/364; H10D62/371; H10D64/00; H10D64/01; H10D64/025
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
146 words
A metal oxide semiconductor transistor comprising: a substrate of a first conductivity-type having a channel region which has a recessed surface; low-concentration source and drain regions of a second conductivity-type disposed on said substrate adjacent to said channel region; high-concentration source and drain regions of the second conductivity-type disposed on said substrate laterally adjacent to said low-concentration source and drain regions; impurity regions of the first conductivity-type enclosing said low-concentration source and drain regions, said high-concentration source and drain regions adjacent to said substrate; an oxide film disposed on said high-concentration source and drain regions; a gate oxide film disposed on said recessed surface and said low-concentration source and drain regions; a gate electrode disposed on said gate oxide film, a lower surface of said gate electrode having a convex portion and at least a flat portion; and a cap oxide film on said gate electrode.
Claim 2
Dependent Claim
146 words
A metal oxide semiconductor transistor comprising: a substrate of a first conductivity-type having a channel region which has a recessed surface; low-concentration source and drain regions of a second conductivity-type disposed on said substrate adjacent to said channel region; high-concentration source and drain regions of the second conductivity-type disposed on said substrate laterally adjacent to said low-concentration source and drain regions; impurity regions of the first conductivity-type enclosing said low-concentration source and drain regions, said high-concentration source and drain regions adjacent to said substrate; an oxide film disposed on said high-concentration source and drain regions; a gate oxide film disposed on said recessed surface and said low-concentration source and drain regions; a gate electrode disposed on said gate oxide film, a lower surface of said gate electrode having a convex portion and at least a flat portion; and a cap oxide film on said gate electrode.
Claim 3
Dependent Claim
25 words
A metal oxide semiconductor transistor of claim 1, wherein top surfaces of said low-concentration source and drain regions are completely overlapped by said gate electrode.
Claim 4
Dependent Claim
23 words
A metal oxide semiconductor transistor of claim 2, wherein said top surfaces of said low-concentration source and drain regions include flat top surfaces.
Claim 5
Dependent Claim
20 words
A metal oxide semiconductor transistor of claim 1, wherein said cap oxide film is thicker than said gate oxide film.
Claim 6
Dependent Claim
30 words
A metal oxide semiconductor transistor of claim 1, wherein said gate oxide film is thinner than said oxide film on said high-concentration source and drain regions of the second conductivity-type.
Claim 7
Dependent Claim
14 words
A metal oxide semiconductor transistor of claim 1, wherein the second conductivity-type is n-type.
Claim 8
Dependent Claim
20 words
A metal oxide semiconductor transistor of claim 1, wherein said high-concentration source and drain regions are directly on said substrate.
Claim 9
Dependent Claim
33 words
A metal oxide semiconductor transistor of claim 1, wherein at least said flat portion of said gate electrode includes a peripheral rim overlying at least one of said low-concentration source and drain regions.
Claim 10
Dependent Claim
32 words
A metal oxide semiconductor transistor of claim 8, wherein said peripheral rim covers a flat portion of a top surface of said at least one of said low-concentration source and drain regions.
Claim 11
Dependent Claim
34 words
A metal oxide semiconductor transistor of claim 1, wherein a lower surface of each of said low-concentration source and drain regions is lower than a lower portion of said recessed surface of said substrate.
Claim 12
Dependent Claim
37 words
A metal oxide semiconductor transistor of claim 1, wherein at least said flat portion of said gate electrode covers a flat portion of a top surface of at least one of said low-concentration source and drain regions.
Claim 13
Dependent Claim
141 words
A metal oxide semiconductor transistor, comprising: a substrate of a first conductivity-type having a channel region which has a recessed surface; low-concentration source and drain regions of a second conductivity-type disposed on said substrate adjacent to said channel region; high-concentration source and drain regions of the second conductivity-type disposed on said substrate laterally adjacent to said low-concentration source and drain regions; an impurity region of the first conductivity-type disposed under said channel region in said substrate; an oxide film disposed on top surfaces of said high-concentration source and drain regions; a gate oxide film disposed on said recessed surface and said low-concentration source and drain regions; a gate electrode disposed on said gate oxide film, a lower surface of said gate electrode having a convex portion and at least a flat portion; and a cap oxide film on said gate electrode.
Claim 14
Dependent Claim
141 words
A metal oxide semiconductor transistor, comprising: a substrate of a first conductivity-type having a channel region which has a recessed surface; low-concentration source and drain regions of a second conductivity-type disposed on said substrate adjacent to said channel region; high-concentration source and drain regions of the second conductivity-type disposed on said substrate laterally adjacent to said low-concentration source and drain regions; an impurity region of the first conductivity-type disposed under said channel region in said substrate; an oxide film disposed on top surfaces of said high-concentration source and drain regions; a gate oxide film disposed on said recessed surface and said low-concentration source and drain regions; a gate electrode disposed on said gate oxide film, a lower surface of said gate electrode having a convex portion and at least a flat portion; and a cap oxide film on said gate electrode.
Claim 15
Dependent Claim
15 words
A metal oxide semiconductor transistor of claim 12, wherein said second conductivity-type is an n-type.
Claim 16
Dependent Claim
25 words
A metal oxide semiconductor transistor of claim 12, wherein entire upper surfaces of said low-concentration source and drain regions are overlapped by said gate electrode.
Claim 17
Dependent Claim
26 words
A metal oxide semiconductor transistor of claim 12, wherein said impurity region of the first conductivity-type is disposed under a central portion of said channel region.
Claim 18
Dependent Claim
23 words
A metal oxide semiconductor transistor of claim 12, wherein at least said flat portion of said gate electrode includes a laterally-extending peripheral rim.
Claim 19
Dependent Claim
32 words
A metal oxide semiconductor transistor of claim 16, wherein said laterally-extending peripheral rim covers a flat portion of a top surface of at least one of said low-concentration source and drain regions.
Claim 20
Dependent Claim
34 words
A metal oxide semiconductor transistor of claim 12, wherein a lower surface of each of said low-concentration source and drain regions is lower than a lower portion of said recessed surface of said substrate.
Claim 21
Dependent Claim
20 words
A metal oxide semiconductor transistor of claim 12, wherein said cap oxide film is thicker than said gate oxide film.
Claim 22
Dependent Claim
31 words
A metal oxide semiconductor transistor of claim 12, wherein said gate oxide film is thinner than said oxide film on said high-concentration source and drain regions of the second conductivity type.
Claim 23
Dependent Claim
37 words
A metal oxide semiconductor transistor of claim 12, wherein at least said flat portion of said gate electrode covers a flat portion of a top surface of at least one of said low-concentration source and drain regions.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-01-26 | 2001-07-28 | 2002-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-01-26 | 2005-07-28 | 2006-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-01-26 | 2009-07-28 | 2010-01-27 | $7700.00 | Window Closed / Lapsed |