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US5689128A
Expired / Lapsed
US
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High density trenched DMOS transistor
Assignee: Vishay Siliconix Inc
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Filing: 1995-08-21
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Granted: 1997-11-18
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Expires: 2015-08-21
Abstract
Abstract The cell density of a trenched DMOS transistor is increased by overcoming the problem of lateral diffusion of deep P+body regions. This problem is solved in three versions. In a first version, the deep P+body region is formed using a high energy implant into a single epitaxial layer. In a second version, a double epitaxial layer is used with a somewhat lower but still high energy deep P+body implant. In a third version, there is no deep P+body implant but only the double epitaxial layer is used. The cell density is improved to more than 12 million cells per square inch in each of the three versions.
Inventors
- 👤 Fwu-Iuan Hshieh
- 👤 Mike F. Chang
- 👤 Kuo-In Chen
- 👤 Richard K. Williams
- 👤 Mohamed Darwish
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:52
CPC Classifications
H; H10; H10D; H10D48/00; H10D48/30; H10D48/32; H10D48/36; H10D30/00; H10D30/60; H10D30/64; H10D30/66; H10D30/668; H10D62/00; H10D62/10; H10D62/13; H10D62/149; H10D62/151; H10D62/156; H10D62/157; H10D62/17; H10D62/393
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
117 words
A field effect transistor comprising: a substrate of a first conductivity type; a first drift region of the first conductivity type having a lower dopant concentration than the substrate and formed on the substrate; a second drift region of the first conductivity type having a dopant concentration intermediate that of the substrate and the first drift region, and overlying the first drift region; a body region of a second conductivity type and overlying the second drift region; a conductive gate electrode extending from a principal surface of the body region into the first drift region; and a source region of the first conductivity type adjacent the conductive gate electrode at the principal surface of the body region.
Claim 2
Dependent Claim
117 words
A field effect transistor comprising: a substrate of a first conductivity type; a first drift region of the first conductivity type having a lower dopant concentration than the substrate and formed on the substrate; a second drift region of the first conductivity type having a dopant concentration intermediate that of the substrate and the first drift region, and overlying the first drift region; a body region of a second conductivity type and overlying the second drift region; a conductive gate electrode extending from a principal surface of the body region into the first drift region; and a source region of the first conductivity type adjacent the conductive gate electrode at the principal surface of the body region.
Claim 3
Dependent Claim
41 words
The transistor of claim 1, wherein a portion of the body region which has a higher dopant concentration than that of a remaining portion thereof extends deeper into the second drift region than does the remaining portion of the body region.
Claim 4
Dependent Claim
27 words
The transistor of claim 2, wherein the portion of the body region having a higher dopant concentration extends to within 1.5 μm of the first drift region.
Claim 5
Dependent Claim
29 words
The transistor of claim 2, wherein the portion of the body region having a higher dopant concentration has a dopant concentration of at least 10 19 /cm 3 .
Claim 6
Dependent Claim
45 words
The transistor of claim 1, further comprising a body contact region of the second conductivity type formed in the body region at the principal surface of the body region and having a higher dopant concentration than that of an adjacent part of the body region.
Claim 7
Dependent Claim
21 words
The transistor of claim 1, wherein a surface area of the transistor is less than 1/12 million of a square inch.
Claim 8
Dependent Claim
17 words
The transistor of claim 1, wherein a maximum thickness of the second drift region is 7 μm.
References Cited (Backward Citations)
JPS57153469A
Cited
US5298442A
Cited
US4931408A
Cited
US5429964A
Cited
US5304831A
Cited
US5404040A
Cited
WO1993003502A1
Cited
US5479037A
Cited
US5316959A
Cited
US5341011A
Cited
US5474943A
Cited
US5410170A
Cited
US5468982A
Cited
US5486772A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-11-17 | 2001-05-19 | 2001-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-11-17 | 2005-05-19 | 2005-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-11-17 | 2009-05-19 | 2009-11-18 | $7700.00 | Window Closed / Lapsed |