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US3881964A
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Annealing to control gate sensitivity of gated semiconductor devices
Assignee: Westinghouse Electric Corp
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Filing: 1973-03-05
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Granted: 1975-05-06
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Expires: 1993-03-05
Abstract
Abstract The gate sensitivity of a gated semiconductor device such as a thyristor or transistor is decreased with precision without significantly changing certain other electrical characteristics of the device. Conducting portions of the device are first masked against irradiation and then gating portions of the device are selectively irradiated to a high level with a suitable radiation such as electron radiation to greatly increase the gate current to fire (Ig). The device is then indiscriminately or selectively annealed, preferably while monitoring the gate current, to reduce the gate current to fire (Ig) to a desired value.
Inventors
- 👤 Michael W Cresswell
- 👤 Richard J Fiedor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:01
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/40; H10D10/441; H10D62/00; H10D62/80; H10D62/83; H10D62/834; H10P; H10P95/00; Y; Y10; Y10S; Y10S148/00; Y10S148/053
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
107 words
A METHOD OF DECREASING GATE SENSITIVITY OF A GATED SEMICONDUCTOR DEVICE WITHOUT SIGNIFICANTLY AFFECTING OTHER ELECTRICAL CHARACTERISTICS OF THE DEVICE COMPRISING THE STEPS OF: A. MASKING CONDUCTING PORTIONS OF A GATED SEMICONDUCTOR DEVICE WITH A FIRST GIVEN GATE SENSITIVITY TO A SECOND GATE FROM A RADIATION SOURCE; B. THEREAFTER DECREASING THE GATE SENSITIVITY TO A SECON GATE SENSITIVITY VALUE BELOW A DESIRED VALUE BY SELECTIVELY IRRADIATING GATING PORTIONS OF THE SEMICONDUCTOR DEVICE WITH THE RADIATION SOURCE; AND C. THEREAFTER INCREASING THE GATE SENSITIVITY TO A THIRD DESIRED GATE SENSITIVITY VALUE BELOW SAID FIRST GATE SENSITIVITY VALUE BY ANNEALING AT LEAST IRRADIATED GATING PORTIONS OF THE SEMICONDUCTOR DEVICE.
Claim 2
Independent Claim
107 words
A METHOD OF DECREASING GATE SENSITIVITY OF A GATED SEMICONDUCTOR DEVICE WITHOUT SIGNIFICANTLY AFFECTING OTHER ELECTRICAL CHARACTERISTICS OF THE DEVICE COMPRISING THE STEPS OF: A. MASKING CONDUCTING PORTIONS OF A GATED SEMICONDUCTOR DEVICE WITH A FIRST GIVEN GATE SENSITIVITY TO A SECOND GATE FROM A RADIATION SOURCE; B. THEREAFTER DECREASING THE GATE SENSITIVITY TO A SECON GATE SENSITIVITY VALUE BELOW A DESIRED VALUE BY SELECTIVELY IRRADIATING GATING PORTIONS OF THE SEMICONDUCTOR DEVICE WITH THE RADIATION SOURCE; AND C. THEREAFTER INCREASING THE GATE SENSITIVITY TO A THIRD DESIRED GATE SENSITIVITY VALUE BELOW SAID FIRST GATE SENSITIVITY VALUE BY ANNEALING AT LEAST IRRADIATED GATING PORTIONS OF THE SEMICONDUCTOR DEVICE.
Claim 3
Dependent Claim
37 words
A method of decreasing gate sensitivity of a gated semiconductor device as set forth in claim 1 wherein: step (a) involves masking substantially all of the conducting portions while leaving substantially all of the gating portions unmasked.
Claim 4
Dependent Claim
42 words
A method of decreasing gate sensitivity of a gated semiconductor device as set forth in claim 1 wherein: step (b) involves irradiating with electron radiation of greater than 1 Mev intensity to a dosage level greater than about 1 X 1013 electrons/cm2.
Claim 5
Dependent Claim
31 words
A method of decreasing gate sensitivity of a gated semiconductor device as set forth in claim 1 wherein: step (c) involves selectively annealing only irradiated gating portions of the semiconductor device.
Claim 6
Dependent Claim
30 words
A method of decreasing gate sensitivity of a gated semiconductor device as set forth in claim 4 comprising the additional step of: d. measuring gate sensitivity while performing step (c).
Claim 7
Independent Claim
115 words
A method of decreasing gate sensitivity of a gated semiconductor device without significantly affecting other electrical characteristics of the device comprising the steps of: a. masking conducting portions of a gated semiconductor device with a first given gate sensitivity against radiation from an electron radiation source; b. thereafter decreasing the gate sensitivity to a second gate sensitivity value below a desired value by irradiating gating portions of the semiconductor device with electron radiation of greater than 1 Mev intensity from the electron radiation source; and c. thereafter increasing the gate sensitivity to a third desired gate sensitivity value below said first gate sensitivity value by annealing at least irradiated gating portions of the semiconductor device.
Claim 8
Independent Claim
115 words
A method of decreasing gate sensitivity of a gated semiconductor device without significantly affecting other electrical characteristics of the device comprising the steps of: a. masking conducting portions of a gated semiconductor device with a first given gate sensitivity against radiation from an electron radiation source; b. thereafter decreasing the gate sensitivity to a second gate sensitivity value below a desired value by irradiating gating portions of the semiconductor device with electron radiation of greater than 1 Mev intensity from the electron radiation source; and c. thereafter increasing the gate sensitivity to a third desired gate sensitivity value below said first gate sensitivity value by annealing at least irradiated gating portions of the semiconductor device.
Claim 9
Dependent Claim
34 words
A method of decreasing gate sensitivity of a gated semiconductor device as set forth in claim 6 wherein: step (b) involves irradiating to a dosage between 1 X 1013 and 1 X 1015 electrons/cm2.
Claim 10
Dependent Claim
34 words
A method of decreasing gate sensitivity of a gated semiconductor device as set forth in claim 7 wherein: step (b) involves irradiating to a dosage between 1 X 1014 and 5 X 1014 electrons/cm2.
Claim 11
Dependent Claim
31 words
A method of decreasing gate sensitivity of a gated semiconductor device as set forth in claim 6 wherein: step (c) involves selectively annealing only irradiated gating portions of the semiconductor device.
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) | 1978-05-05 | 1978-11-04 | 1979-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-05 | 1982-11-04 | 1983-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-05 | 1986-11-04 | 1987-05-06 | $7700.00 | Window Closed / Lapsed |