US4642667A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrated circuits
Assignee: STC PLC
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Filing: 1984-10-17
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Granted: 1987-02-10
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Expires: 2004-10-17
Abstract
Abstract A bipolar lateral transistor is formed in a highly doped p - -type well (13) the base contained in a lightly doped n - -type well (12) the collector in a very lightly doped p -- -type substrate (11). The arrangement is such that the boundary of the collector/base depletion region is distributed so that the non-depleted base region is wide below the emitter but very narrow at the surface. This defines a narrow active base region in the lateral emitter-collector path thus ensuring that the transistor operates predominantly in its lateral rather than its vertical mode. The structure is compatible with conventional CMOS and NMOS processing techniques.
Inventors
- 👤 Terence E. Magee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:38
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/60; H10D84/00; H10D84/40; H10D84/401
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
247 words
An MOS compatible bipolar transistor structure comprising an npn lateral high gain transistor and an npn vertical low gain transistor formed in a lightly doped n - -type well in a major surface of a very lightly doped p -- -type substrate, the structure comprising a lightly doped p - -type well found in the n - -type well, a p + -region and p-type region formed in the p - -type well, a first n + -type region formed in said p-type region, and a second n + -type region formed at the surface boundary between the p - -type well and the n - -type well, wherein said first n + -type region provides a common emitter of both said transistors, wherein said second n + -type region provides the collector of the lateral transistor and a collector contact of the vertical transistor, wherein said p + -type region provides a base contact of both said transistors, wherein said p-type region provides the base of the lateral transistor and, together with the p - -type well, the base of the vertical transistor, and wherein a depletion region is disposed across the boundary between the p - -type and n - -type wells, the boundary being narrow adjacent the lateral transistor base so as to provide a high lateral gain and wide adjacent the vertical transistor base so as to provide a low vertical gain, whereby the structure, in use, acts predominantly in a lateral mode.
Claim 2
Dependent Claim
247 words
An MOS compatible bipolar transistor structure comprising an npn lateral high gain transistor and an npn vertical low gain transistor formed in a lightly doped n - -type well in a major surface of a very lightly doped p -- -type substrate, the structure comprising a lightly doped p - -type well found in the n - -type well, a p + -region and p-type region formed in the p - -type well, a first n + -type region formed in said p-type region, and a second n + -type region formed at the surface boundary between the p - -type well and the n - -type well, wherein said first n + -type region provides a common emitter of both said transistors, wherein said second n + -type region provides the collector of the lateral transistor and a collector contact of the vertical transistor, wherein said p + -type region provides a base contact of both said transistors, wherein said p-type region provides the base of the lateral transistor and, together with the p - -type well, the base of the vertical transistor, and wherein a depletion region is disposed across the boundary between the p - -type and n - -type wells, the boundary being narrow adjacent the lateral transistor base so as to provide a high lateral gain and wide adjacent the vertical transistor base so as to provide a low vertical gain, whereby the structure, in use, acts predominantly in a lateral mode.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |