US3840887A
Expired / Lapsed
US
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Selective irradiation of gated semiconductor devices to control gate sensitivity
Assignee: Westinghouse Electric Corp
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Filing: 1972-08-25
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Granted: 1974-10-08
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Expires: 1992-08-25
Abstract
Abstract By selective irradiation, the gate sensitivity of gated semiconductor devices such as thyristors and transistors is controlled without changing certain other electrical characteristics of the device. Decreased gate sensitivity is achieved without corresponding increases in forward voltage drop by masking conducting portions of the device against radiation, such as electron radiation, and irradiating gating portions of the device with suitable radiation such as electron radiation. Further, gate sensitivity can be maintained while reducing turnoff times and/or increasing blocking voltages by masking gating portions of the device against radiation, such as electron radiation, and irradiating conducting portions and/or peripheral portions of the device with suitable radiation such as electron radiation.
Inventors
- 👤 J Roberts
- 👤 M Cresswell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:18
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/80; H10D62/83; H10D62/834; H10D99/00; H10P; H10P95/00
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
65 words
A method of controlling gate sensitivity of a gated semiconductor device without significantly affecting other electrical characteristics of the device comprising the steps of: a. masking against radiation from a radiation source a portion of the semiconductor device selected from at least the grOup consisting of the gating and conducting portions; and b. thereafter irradiating unmasked portions of the semiconductor device with the radiation source.
Claim 2
Independent Claim
65 words
A method of controlling gate sensitivity of a gated semiconductor device without significantly affecting other electrical characteristics of the device comprising the steps of: a. masking against radiation from a radiation source a portion of the semiconductor device selected from at least the grOup consisting of the gating and conducting portions; and b. thereafter irradiating unmasked portions of the semiconductor device with the radiation source.
Claim 3
Dependent Claim
34 words
A method of controlling gate sensitivity of a gated semiconductor device without significantly affecting other electrical characteristics of the device as set forth in claim 1 wherein: the radiation source is an electron beam.
Claim 4
Dependent Claim
38 words
A method of controlling gate sensitivity of a gated semiconductor device without significantly affecting other electrical characteristics of the device as set forth in claim 2 wherein: the electron beam has an intensity greater than about 1 Mev.
Claim 5
Independent Claim
54 words
A method of decreasing the gate sensitivity of a gated semiconductor device without significantly increasing the forward voltage drop of the device comprising the steps of: a. masking against radiation from a radiation source conducting portions of the semiconductor device; and b. thereafter irradiating gating portions of the semiconductor device with the radiation source.
Claim 6
Independent Claim
54 words
A method of decreasing the gate sensitivity of a gated semiconductor device without significantly increasing the forward voltage drop of the device comprising the steps of: a. masking against radiation from a radiation source conducting portions of the semiconductor device; and b. thereafter irradiating gating portions of the semiconductor device with the radiation source.
Claim 7
Dependent Claim
35 words
A method of decreasing gate sensitivity of a gated semiconductor device without significantly increasing the forward voltage drop of the device as set forth in claim 4 wherein: the radiation source is an electron beam.
Claim 8
Dependent Claim
39 words
A method of decreasing gate sensitivity of a gated semiconductor device without significantly increasing the forward voltage drop of the device as set forth in claim 5 wherein: the electron beam has an intensity greater than about 1 Mev.
Claim 9
Independent Claim
53 words
A method of maintaining gate sensitivity of a gated semiconductor device while changing other electrical characteristics of the device comprising the steps of: a. masking against radiation from a radiation source gating portions of the semiconductor device; and b. thereafter irradiating conducting portions of the semiconductor device against radiation from a radiation source.
Claim 10
Independent Claim
53 words
A method of maintaining gate sensitivity of a gated semiconductor device while changing other electrical characteristics of the device comprising the steps of: a. masking against radiation from a radiation source gating portions of the semiconductor device; and b. thereafter irradiating conducting portions of the semiconductor device against radiation from a radiation source.
Claim 11
Dependent Claim
33 words
A method of maintaining gate sensitivity of a gated semiconductor device while changing other electrical characteristics of the device as set forth in claim 7 wherein: the radiation source is an electron beam.
Claim 12
Dependent Claim
48 words
A method of maintaining gate sensitivity of a gated semiconductor device while changing other electrical characteristics of the device as set forth in claim 7 comprising the additional step of masking peripheral portions of the semiconductor device against radiation from the radiation source prior to said irradiation step.
Claim 13
Dependent Claim
43 words
A method of maintaining gate sensitivity of a gated semiconductor device while changing other electrical characteristics of the device as set forth in claim 7 comprising in addition: irradiating peripheral portions of the semiconductor device while irradiating the conducting portions of the device.
Claim 14
Dependent Claim
42 words
A gated semiconductor device comprising: semiconductor body comprising a conducting portion and a gating portion, said conducting portion having been irradiated to change electrical characteristics of the device, and said gating portion having been nonirradiated to maintain gate sensitivity of the device.
Claim 15
Dependent Claim
42 words
A gated semiconductor device comprising: semiconductor body comprising a conducting portion and a gating portion, said conducting portion having been irradiated to change electrical characteristics of the device, and said gating portion having been nonirradiated to maintain gate sensitivity of the device.
Claim 16
Dependent Claim
39 words
A gated semiconductor device as set forth in claim 11 wherein: the semiconductor body comprises in addition a peripheral portion, said peripheral portion having been irradiated to increase blocking voltage while maintaining the forward voltage drop of the device.
Claim 17
Dependent Claim
45 words
A gated semiconductor device comprising: a semiconductor body comprising a gating portion and a conducting portion, said gating portion having been irradiated to increase gate current of the device, and said conducting portion having been nonirradiated to maintain the forward voltage drop of the device.
Claim 18
Dependent Claim
45 words
A gated semiconductor device comprising: a semiconductor body comprising a gating portion and a conducting portion, said gating portion having been irradiated to increase gate current of the device, and said conducting portion having been nonirradiated to maintain the forward voltage drop of the device.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |