US4654688A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor device having a transistor with increased current amplification factor
Assignee: Fujitsu Ltd
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Filing: 1984-12-27
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Granted: 1987-03-31
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Expires: 2004-12-27
Abstract
Abstract A semiconductor device having a lateral transistor consisting of a semiconductor substrate, a first semiconductor region, and a second semiconductor region operatively functioning as a collector, a base, and an emitter of a transistor. By providing a high concentration region in the first semiconductor region, the base width of the transistor is narrowed. In a PROM, a reverse current preventing transistor with such a narrowed base width in each memory cell can be driven by a decoder/driver with a lowered driving power consumption.
Inventors
- 👤 Toshitaka Fukushima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 00:30
CPC Classifications
H; H10; H10B; H10B20/00; H10B20/20; G; G11; G11C; G11C17/00; G11C17/14; G11C17/16; H10B69/00; H10D; H10D30/00; H10D30/01; H10D30/051; H10D30/80; H10D30/83; H10D62/00; H10D62/10; H10D62/17; H10D62/177; H10D8/00; H10D8/01; H10D8/045; H10D8/411; H10W; H10W15/00; H10W15/01; H10W20/00; H10W20/40; H10W20/49; H10W20/493
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
135 words
A semiconductor device comprising: a semiconductor substrate of a first conductivity type; a first semiconductor region on said semiconductor substrate, of a second conductivity type opposite to said first conductivity type; a second semiconductor region in said first semiconductor region, of said first conductivity type; a high concentration buried region under said second semiconductor region, located partially in said first semiconductor region and partially in said semiconductor substrate underneath and contiguous to said first semiconductor region, said buried region being of said second conductivity type but with a higher impurity concentration than that of said first semiconductor region; and a further buried region, of said first conductivity type, located under said second semiconductor region and partially in said first semiconductor region and partially in said semiconductor substrate underneath and contiguous to said first semiconductor region.
Claim 2
Dependent Claim
135 words
A semiconductor device comprising: a semiconductor substrate of a first conductivity type; a first semiconductor region on said semiconductor substrate, of a second conductivity type opposite to said first conductivity type; a second semiconductor region in said first semiconductor region, of said first conductivity type; a high concentration buried region under said second semiconductor region, located partially in said first semiconductor region and partially in said semiconductor substrate underneath and contiguous to said first semiconductor region, said buried region being of said second conductivity type but with a higher impurity concentration than that of said first semiconductor region; and a further buried region, of said first conductivity type, located under said second semiconductor region and partially in said first semiconductor region and partially in said semiconductor substrate underneath and contiguous to said first semiconductor region.
Claim 3
Dependent Claim
36 words
A semiconductor device as set forth in claim 1, comprising a transistor with its collector region, base region and emitter region formed of said semiconductor substrate, said first semiconductor region and said second semiconductor region, respectively.
Claim 4
Dependent Claim
37 words
A semiconductor device as set forth in claim 2, wherein the distance between the top surface of said further buried region and the bottom surface of said second semiconductor region determines the base width of said transistor.
Claim 5
Dependent Claim
16 words
A semiconductor device as set forth in claim 3, wherein said transistor is a PNP transistor.
Claim 6
Dependent Claim
25 words
The device of claim 1, said further buried region having a higher conductivity than said semiconductor substrate and having a portion extending into said substrate.
Claim 7
Dependent Claim
131 words
A semiconductor device comprising: a semiconductor substrate of a first conductivity type; a first semiconductor region on said semiconductor substrate, of a second conductivity type opposite to said first conductivity type; a second semiconductor region in said first semiconductor region, of said firs conductivity type; a high concentration buried region under said second semiconductor region, located partially in said first semiconductor region and partially in said semiconductor substrate underneath and contiguous to said first semiconductor region, said buried region being of said second conductivity type but with a higher impurity concentration than the impurity concentration in said first semiconductor region; and said second semiconductor region having projections extending toward said semiconductor substrate, said projections being formed in a part of said first semiconductor region apart from said high concentration buried region.
Claim 8
Dependent Claim
131 words
A semiconductor device comprising: a semiconductor substrate of a first conductivity type; a first semiconductor region on said semiconductor substrate, of a second conductivity type opposite to said first conductivity type; a second semiconductor region in said first semiconductor region, of said firs conductivity type; a high concentration buried region under said second semiconductor region, located partially in said first semiconductor region and partially in said semiconductor substrate underneath and contiguous to said first semiconductor region, said buried region being of said second conductivity type but with a higher impurity concentration than the impurity concentration in said first semiconductor region; and said second semiconductor region having projections extending toward said semiconductor substrate, said projections being formed in a part of said first semiconductor region apart from said high concentration buried region.
Claim 9
Dependent Claim
36 words
A semiconductor device as set forth in claim 6, comprising a transistor with its collector region, base region and emitter region formed of said semiconductor substrate, said first semiconductor region, and said second semiconductor region, respectively.
Claim 10
Dependent Claim
39 words
A semiconductor device as set forth in claim 7, wherein the distance between the top surface of said semiconductor substrate and the bottom surface of said projections of said second semiconductor region determines the base width of said transistor.
Claim 11
Dependent Claim
16 words
A semiconductor device as set forth in claim 8, wherein said transistor is a PNP transistor.
Claim 12
Dependent Claim
16 words
A semiconductor device as set forth in claim 8, wherein said transistor is an NPN transistor.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1990-03-30 | 1990-09-29 | 1991-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-30 | 1994-09-29 | 1995-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-30 | 1998-09-29 | 1999-03-31 | $7700.00 | Window Closed / Lapsed |