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Patent US5741737A successfully refreshed from Google Patents.
US5741737A
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MOS transistor with ramped gate oxide thickness and method for making same
Assignee: Cypress Semiconductor Corp
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Filing: 1996-12-17
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Granted: 1998-04-21
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Expires: 2016-12-17
Abstract
Abstract The invention relates to a transistor having a ramped gate oxide thickness, a semiconductor device containing the same and a method for making a transistor.
Inventors
- 👤 Mark T. Kachelmeier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 00:09
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/60; H10D64/66; H10D64/68; H10D64/693; H10D30/00; H10D30/01; H10D30/021; H10D30/0221; H10D30/60; H10D64/01; H10D64/013; H10D64/01302; H10D64/01332; H10D64/01336; H10D64/20; H10D64/27; H10D64/311; H10D64/411; H10D64/511; H10D64/514; H10D64/516; H10D64/01342; H10D64/691; Y; Y10; Y10S; Y10S438/00; Y10S438/981
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
66 words
A method of forming of semiconductor transistor comprising i) applying a gate mask to a source region edge of a patterned gate material, leaving a drain region edge of said patterned gate material exposed; and ii) oxidizing said gate material such that a gate oxide is formed having a thickness at a drain region edge which is greater than a thickness at a source region edge.
Claim 2
Independent Claim
66 words
A method of forming of semiconductor transistor comprising i) applying a gate mask to a source region edge of a patterned gate material, leaving a drain region edge of said patterned gate material exposed; and ii) oxidizing said gate material such that a gate oxide is formed having a thickness at a drain region edge which is greater than a thickness at a source region edge.
Claim 3
Dependent Claim
15 words
The method of claim 1, wherein said gate mask is Si 3 N 4 .
Claim 4
Dependent Claim
20 words
The method of claim 1, wherein said gate material is oxidized by steam oxidation at a temperature of 700°-1100° C.
Claim 5
Dependent Claim
11 words
The method of claim 1, wherein said gate material is polysilicon.
Claim 6
Dependent Claim
12 words
The method of claim 1, wherein said gate oxide is silicon dioxide.
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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) | 2001-04-20 | 2001-10-20 | 2002-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-04-20 | 2005-10-20 | 2006-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-04-20 | 2009-10-20 | 2010-04-21 | $7700.00 | Window Closed / Lapsed |