US3616403A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Prevention of inversion of p-type semiconductor material during rf sputtering of quartz
Assignee: International Business Machines Corp
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Filing: 1968-10-25
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Granted: 1971-10-26
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Expires: 1988-10-25
Abstract
Abstract Method for preventing inversion of semiconductor surfaces during RF sputtering of dielectrics by maintaining a low flat band charge level at the semiconductor interface. The flat band charge level is controlled by rigidly maintaining various parameters of the sputtering system such as target purity, and RF power density, in conjunction with the presence of a thin layer of phosphosilicate glass on the semiconductor which is supported on a dielectric material in floating mode.
Inventors
- 👤 Robert H Collins
- 👤 Joseph S Logan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:40
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/34; C; C23; C23C; C23C14/00; C23C14/06; C23C14/10; H10; H10W; H10W74/00; H10W74/40; H10W74/43
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
25 words
The method of claim 1 wherein the positive impurity ion density of said target is of the order of 1 X 1017 ions per cm.3.
Claim 2
Dependent Claim
22 words
The method of claim 1 wherein said power density is maintained in the range of 15 to 20 watts per square inch.
Claim 3
Dependent Claim
21 words
The method of claim 1 wherein said phosphosilicate glass layer thickness is in the range of 650 to 3,000 A. thick.
Claim 4
Dependent Claim
17 words
A method of claim 1 wherein said layer of phosphosilicate glass is at least 1,000 A. thick.
Claim 5
Independent Claim
23 words
The method of claims 1, 2, 3, 4, or 5, wherein said semiconductor is primarily silicon and said target is primarily silicon dioxide.
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) | 1974-10-25 | 1975-04-26 | 1975-10-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-25 | 1979-04-26 | 1979-10-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-25 | 1983-04-26 | 1983-10-26 | $7700.00 | Window Closed / Lapsed |