US3867196A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for selectively establishing regions of different surface charge densities in a silicon wafer
Assignee: Smc Microsystems Corp
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Filing: 1974-03-11
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Granted: 1975-02-18
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Expires: 1994-03-11
Abstract
Abstract A process is described whereby regions having selectively different values of fixed positive surface charge density, Qss, are formed on a common silicon wafer. In the process, a material which acts as a barrier to oxygen, such as silicon nitride, is placed over a selected portion of the surface of the silicon, thereby to simulate a final anneal in an inert atmosphere only at the portion of the silicon surface underlying the oxygen barrier and to establish there a minimum value of Qss.
Inventors
- 👤 Paul Richman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:45
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/17; H10D62/213; H10D62/221; H10D62/235; H10D84/00; H10D84/80; H10D84/82; H10D84/83; H10D84/84; H10D99/00; H10P; H10P14/00; H10P14/60; H10P14/61; H10P14/63; H10P14/6302; H10P14/6304; H10P14/6306; H10P14/6308; H10P14/6309; H10P14/6322; H10P14/65; H10P14/6516; H10P14/6529; H10P95/00; H10W; H10W74/00; H10W74/40; Y; Y10; Y10S; Y10S148/00; Y10S148/003; Y10S148/113; Y10S148/114; Y10S438/00; Y10S438/91
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
98 words
A PROCESS FOR FABRICATING A SEMICONDUCTOR INTEGRATED CIRCUIT COMPRISING THE STEPS OF PROVIDING A SILICON SUBSTRATE, FORMING A SILICON DIOXIDE LAYER OVER SAID SILICON SUBSTRATE, FORMING A FILM OF A MATERIAL HAVING THE CHARACTERISTIC OF ACTING AS A BARRIER TO OXYGEN OVER A SELECTED PORTION OF SAID OXIDIZED SILICON SUBSTRATE, AND THEREAFTER SUBJECTING SAID SILICON SUBSTRATE TO AN ANNEAL IN AN OXYGEN-CONTAINING ATMOSPHERE, WHEREBY A MINIMUM VALUE OF QSS IS ESTABILISHED IN SAID PORTION OF SAID SILICON SUBSTRATE UNDERLYING SAID OXYGEN-BARRIER FILM AND A HIGHER VALUE OF QSS IS ESTABILISHED IN THE REMAINING PORTION OF SAID SILICON SUBSTRATE.
Claim 2
Dependent Claim
98 words
A PROCESS FOR FABRICATING A SEMICONDUCTOR INTEGRATED CIRCUIT COMPRISING THE STEPS OF PROVIDING A SILICON SUBSTRATE, FORMING A SILICON DIOXIDE LAYER OVER SAID SILICON SUBSTRATE, FORMING A FILM OF A MATERIAL HAVING THE CHARACTERISTIC OF ACTING AS A BARRIER TO OXYGEN OVER A SELECTED PORTION OF SAID OXIDIZED SILICON SUBSTRATE, AND THEREAFTER SUBJECTING SAID SILICON SUBSTRATE TO AN ANNEAL IN AN OXYGEN-CONTAINING ATMOSPHERE, WHEREBY A MINIMUM VALUE OF QSS IS ESTABILISHED IN SAID PORTION OF SAID SILICON SUBSTRATE UNDERLYING SAID OXYGEN-BARRIER FILM AND A HIGHER VALUE OF QSS IS ESTABILISHED IN THE REMAINING PORTION OF SAID SILICON SUBSTRATE.
Claim 3
Dependent Claim
30 words
The process of claim 1, in which said film further acts as a barrier to water vapor and said annealing step is carried out in an environment containing water vapor.
Claim 4
Dependent Claim
15 words
The process of claim 2, in which said oxygen-barrier film is a silicon nitride film.
Claim 5
Dependent Claim
15 words
The process of claim 1, in which said oxygen-barrier film is a silicon nitride film.
Claim 6
Dependent Claim
20 words
The process of claim 4, in which the thickness of said silicon nitride film is between 400 and 3,000 A.
Claim 7
Dependent Claim
21 words
The process of claim 4, in which said annealing step is carried out at a temperature of between 550*C and 1250*C.
References Cited (Backward Citations)
US3472689A
Cited
US3793088A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |