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Patent US4769688A successfully refreshed from Google Patents.
US4769688A
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Power bipolar transistor
Assignee: Texas Instruments Inc
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Filing: 1987-07-16
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Granted: 1988-09-06
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Expires: 2007-07-16
Abstract
Abstract A bipolar power transistor having a plurality of elongated emitter parts connected to a common emitter metallization is provided with a shaped resistive region between the emitter parts and the emitter metallization, in order to compensate for differences in the resistance presented by the metallization itself.
Inventors
- 👤 David R. Cotton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 13:34
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/124; H10D62/126; H10D84/00; H10D84/101; H10D84/121; H10D84/125
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
112 words
A bipolar transistor patterned in the surface of a semiconductor substrate, having a collector region, a base region, an emitter terminal, and a plurality of elongated emitter parts; a common emitter metallization; a resistive region in said semiconductor surface located between and in contact with said emitter parts and said metallization, said resistive region having a tapered geometry such that the resistive region becomes progressively more narrow with increasing distance from said emitter terminal, to provide a reduced resistance adjacent those portions of said metallization which are more distant from said emitter terminal, in order to compensate for the difference in resistance presented by the metallization at different parts of the transistor.
Claim 2
Dependent Claim
112 words
A bipolar transistor patterned in the surface of a semiconductor substrate, having a collector region, a base region, an emitter terminal, and a plurality of elongated emitter parts; a common emitter metallization; a resistive region in said semiconductor surface located between and in contact with said emitter parts and said metallization, said resistive region having a tapered geometry such that the resistive region becomes progressively more narrow with increasing distance from said emitter terminal, to provide a reduced resistance adjacent those portions of said metallization which are more distant from said emitter terminal, in order to compensate for the difference in resistance presented by the metallization at different parts of the transistor.
Claim 3
Dependent Claim
30 words
A bipolar transistor as claimed in claim 1 in which said tapered geometry is such that the temperature attained throughout the transistor is substantially uniform when operating under predetermined conditions.
Claim 4
Dependent Claim
25 words
A bipolar transistor as claimed in claim 1 in which the tapered geometry is such that the current density through the transistor is substantially uniform.
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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) | 1991-09-06 | 1992-03-07 | 1992-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-06 | 1996-03-07 | 1996-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-06 | 2000-03-07 | 2000-09-06 | $7700.00 | Window Closed / Lapsed |