Patent US3571674A successfully refreshed from Google Patents.
US3571674A
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Fast switching pnp transistor
Assignee: Fairchild Semiconductor Corp
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Filing: 1969-01-10
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Granted: 1971-03-23
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Expires: 1989-01-10
Abstract
Abstract The on-off switching time of a PNP transistor is significantly decreased by placing a Schottky Barrier diode in parallel with the collector-base PN junction of the transistor.
Inventors
- 👤 Albert Y C Yu
- 👤 Edward H Snow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:53
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/60; H10D84/611; H10D84/619; H10D84/613; H10D84/617; H10D99/00; Y; Y10; Y10S; Y10S148/00; Y10S148/037; Y10S148/085; Y10S148/096
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
39 words
Structure as in claim 1 wherein said Ohmic contacts comprise a metal selected from the group consisting of aluminum, gold, nickel, platinum and molybdenum and said metal layer likewise comprises a metal selected from this same group of metals.
Claim 2
Dependent Claim
27 words
Structure as in claim 2 wherein said collector, base and emitter regions comprise selectively doped silicon, said ohmic contacts comprise aluminum, and said metal layer comprises aluminum.
Claim 3
Dependent Claim
185 words
A fast switching transistor comprising: a P-type collector region with an impurity concentration ranging from 1014 to 1017 atoms per cubic centimeter; an N-type base region epitaxially-grown on said P-type collector region with an impurity concentration no greater than about 1017 atoms per cubic cubic centimeter; a P-type emitter region diffused into, and forming a PN junction with said epitaxially-grown N-type region, said emitter region having an impurity concentration of approximately 1019 atoms per cubic centimeter; selected ohmic contacts to said emitter, said base and said collector regions; a Schottky Barrier diode connecting said base region to said collector region, said Schottky Barrier diode comprising a metal layer attached to adjacent portions of both said P-type collector region and said epitaxilally-grown N-type base region, thereby to form a Schottky Barrier junction with said N-type base region and an ohmic junction with said P-type collector region; and an extension of said metal layer on insulation over a portion of said epitaxially grown N-type base region, thereby to shape the electric field in said N-type base region to improve the breakdown voltage of said Schottky Barrier junction.
Claim 4
Dependent Claim
162 words
A fast-switching transistor comprising: a P+-type collector region; an N-type base region epitaxially-grown on said P+-type collector region; a P+-type emitter region diffused into, and forming a PN junction with said epitaxially-grown N-type region; a P+-type collector contact region diffused through said epitaxially-grown N-type region into contact with said P+-type collector region; selected ohmic contacts to said emitter, said base and said collector contact regions; a Schottky Barrier diode connecting said base region to said collector region, said Schottky Barrier diode comprising a metal layer attached to adjacent portions of both said P+-type collector contact region and said epitaxially-grown N-type base region, thereby to form a Schottky Barrier junction with said N-type base region and an ohmic junction with said P+-type collector contact region; and an extension of said metal layer on insulation over a portion of said N-type base region, thereby to shape the electric field in said N-type base region to improve the breakdown voltage of said Schottky Barrier junction.
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) | 1974-03-22 | 1974-09-21 | 1975-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-22 | 1978-09-21 | 1979-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-22 | 1982-09-21 | 1983-03-23 | $7700.00 | Window Closed / Lapsed |