Patent US3766637A successfully refreshed from Google Patents.
US3766637A
Expired / Lapsed
US
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Method of making mos transistors
Assignee: RCA Corp
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Filing: 1972-05-04
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Granted: 1973-10-23
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Expires: 1992-05-04
Abstract
Abstract A method of making a complementary pair of N channel and P channel MOS transistors using aluminum oxide as the gate insulator material, in which the threshold voltage of the P channel unit is controlled to be in the -1 to -1.5 volt range by causing accumulation of N type dopants in the surface layer of the semiconductor body prior to deposition of the aluminum oxide. At the same time, the N channel unit is protected so that P type dopants are not unduly depleted from the surface layer of the semiconductor before deposition of aluminum oxide.
Inventors
- 👤 P Norris
- 👤 J Shaw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:50
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0165; H10D84/0167; H10D84/02; H10D84/03; H10D84/038; H10D99/00; Y; Y10; Y10S; Y10S148/00; Y10S148/043; Y10S148/053; Y10S148/118; Y10S438/00; Y10S438/91; Y10S438/914; Y10S438/92
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
29 words
A method according to claim 1 in which said steam is at a temperature of about 900* C and the time of treatment is about 60 to 100 minutes.
Claim 2
Dependent Claim
14 words
A method according to claim 1 in which said aluminum oxide is deposited pyrohydrolytically.
Claim 3
Dependent Claim
14 words
A method according to claim 1 in which said protective coating is silicon nitride.
Claim 4
Dependent Claim
63 words
A method according to claim 3 in which said aluminum oxide is deposited at a growth rate of about 50 - 125 A/min., the deposited aluminum oxide layer is annealed at growth temperature in hydrogen for at least 10 minutes, and the annealed layer is then slow-cooled in hydrogen until the temperature of the silicon body decreases to about 300* - 400* C.
Claim 5
Dependent Claim
20 words
A method according to claim 5 in which said slow cooling is at a rate of 20* - 25* C./min.
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) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |