Patent US3893153A successfully refreshed from Google Patents.
US3893153A
Expired / Lapsed
US
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Light activated thyristor with high di/dt capability
Assignee: Westinghouse Electric Corp
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Filing: 1974-01-10
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Granted: 1975-07-01
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Expires: 1994-01-10
Abstract
Abstract A light activated thyristor with high dI/dt capability is provided by disposing first and second thyristors, one a primary and one a pilot thyristor, in a semiconductor body having first and second major surfaces. The two thristors have common cathodebase, anode-base and anode-emitter regions, and have spaced apart cathode-emitter regions adjoining the first major surface of the body. The common cathode-base region adjoins the first major surface between the two thyristors as well as intermittently of the cathode-emitter region of the first thyristor to form shunts. The first major surface at the cathode-emitter region of the second thyristor is adapted for activation of the second thyristor therethrough with electromagnetic radiation of wavelengths corresponding substantially to the energy bandgap of the semiconductor body. The cathode electrode makes ohmic contact with the cathode-emitter region of the first thyristor and the common cathode-base region at the shunts, and the anode electrode makes ohmic contact with the common anode-emitter regions. A floating contact also makes ohmic contact to the cathode-emitter region of the second thyristor and the common cathode-base region between the thyristors, while leaving exposed substantial portions of the first major surface adjoining the cathode-emitter region of the second thyristor.
Inventors
- 👤 Derrick J Page
- 👤 John S Roberts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:56
CPC Classifications
H; H10; H10F; H10F30/00; H10F30/20; H10F30/21; H10F30/26; H10F30/263
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
301 words
A light activated thyristor with high dI/dt capability comprising: A. first and second thyristors disposed in a semiconductor body having first and second major surfaces; each thyristor having four impurity regions extending through the body between the major surfaces; said impurity regions of alternate carrier-type disposed alternately with the PN junctions formed between adjacent regions; the two regions interior being cathode-base and anode-base regions, and the two regions adjoining the first and second major surfaces and adjoining the cathode-base and anode-base regions,respectively, being cathode-emitter and anode-emitter regions, respectively; B. the cathode-base, anode-base and anode-emitter regions of the first and second thyristors being common to both thyristors; C. said common cathode base region adjoining the first major surface intermittently of the cathode-emitter region of the first thyristor to form shunts, and between the cathode-emitter regions of the first and second thyristor such that the cathode-emitter regions are spaced apart; D. portions of the fiRst surface adjoining the cathode-emitter region of the second thyristor adapted for activation of the second thyristor therethrough by electromagnetic radiation of wavelengths corresponding substantially to the bandgap energy of the semiconductor material of the body; E. cathode and anode electrodes disposed on first and second major surfaces, respectively, of the semiconductor body and making ohmically contact with the cathode-emitter region of the first thyristor and the common anode-emitter region of both thyristors, respectively, said cathode electrode also making ohmic contact with the cathode-base region at the shunts through the cathode-emitter region of the first thyristor; and F. a floating contact positioned on the first major surface to make ohmic contact with the common cathode-base region between the thyristors and the cathode-emitter region of the second thyristor, while leaving exposed for light activation therethrough substantial portions of the first major surface adjoining the cathode-emitter region of the second thyristor.
Claim 2
Dependent Claim
301 words
A light activated thyristor with high dI/dt capability comprising: A. first and second thyristors disposed in a semiconductor body having first and second major surfaces; each thyristor having four impurity regions extending through the body between the major surfaces; said impurity regions of alternate carrier-type disposed alternately with the PN junctions formed between adjacent regions; the two regions interior being cathode-base and anode-base regions, and the two regions adjoining the first and second major surfaces and adjoining the cathode-base and anode-base regions,respectively, being cathode-emitter and anode-emitter regions, respectively; B. the cathode-base, anode-base and anode-emitter regions of the first and second thyristors being common to both thyristors; C. said common cathode base region adjoining the first major surface intermittently of the cathode-emitter region of the first thyristor to form shunts, and between the cathode-emitter regions of the first and second thyristor such that the cathode-emitter regions are spaced apart; D. portions of the fiRst surface adjoining the cathode-emitter region of the second thyristor adapted for activation of the second thyristor therethrough by electromagnetic radiation of wavelengths corresponding substantially to the bandgap energy of the semiconductor material of the body; E. cathode and anode electrodes disposed on first and second major surfaces, respectively, of the semiconductor body and making ohmically contact with the cathode-emitter region of the first thyristor and the common anode-emitter region of both thyristors, respectively, said cathode electrode also making ohmic contact with the cathode-base region at the shunts through the cathode-emitter region of the first thyristor; and F. a floating contact positioned on the first major surface to make ohmic contact with the common cathode-base region between the thyristors and the cathode-emitter region of the second thyristor, while leaving exposed for light activation therethrough substantial portions of the first major surface adjoining the cathode-emitter region of the second thyristor.
Claim 3
Dependent Claim
33 words
A light activated thyristor with high dI/dt capability as set forth in claim 1 wherein: the second thyristor is positioned centrally of the first thyristor, and the floating contact is annular in shape.
Claim 4
Dependent Claim
33 words
A light activated thyristor with high dI/dt caability as set forth in claim 1 wherein: the second thyristor is positioned peripherally of the first thyristor and the floating contact is annular in shape.
References Cited (Backward Citations)
US3577046A
Cited
US3697833A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-30 | 1978-12-30 | 1979-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-30 | 1982-12-30 | 1983-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-30 | 1986-12-30 | 1987-07-01 | $7700.00 | Window Closed / Lapsed |