US3928093A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making a bi-directional solid state device
Assignee: Nortel Networks Ltd
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Filing: 1974-06-03
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Granted: 1975-12-23
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Expires: 1994-06-03
Abstract
Abstract This invention is concerned with the method of making a semiconductor device having a bi-directional changeover characteristic from high impedance to low impedance at a predetermined voltage. The device is a fine layer device of essentially symmetrical form either side of a central substrate, for example N-P-N-P-N. A typical device has a central substrate layer, an outer layer on each surface of the substrate, a base region on each surface of the substrate defined by the oxide layers, an emitter region in each base region and an electrically conducting layer on each side of the substrate and in contact with related base and emitter regions. The layers, regions and other items are simultaneously produced on each side of the substrate, similar regions on each side of the substrate in alignment.
Inventors
- 👤 Tongerloo Eric Henry Van
- 👤 Abd-El-Fattah Ali Ibrahim
- 👤 Douglas Roy Colton
- 👤 John Lawrence
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:14
CPC Classifications
H; H10; H10D; H10D8/00; H10D8/80; H10W; H10W72/00; H10W74/00; H10W74/10; H10W74/111; H10W76/00; H10W76/10; H10W76/12; H10W76/13; H10W76/138; Y; Y10; Y10S; Y10S438/00; Y10S438/981
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
51 words
A PROCESS FOR MAKING A BI-DIRECTIONAL SOLID STATE DEVICE, COMPRISING: FORMING AN OXIDE LAYER ON EACH SURFACE OF A SUBSTRATE WAFER OF ONE SEMICONDUCTOR TYPE; PHOTOENGRAVING SIMULTANEOUSLY ON BOTH SIDES OF SAID WAFER TO DEFINE ALIGNED BASE REGIONS; SIMULTANEOUSLY DIFFUSING BASE REGIONS TO HAVE A SEMICONDUCTOR TYPE OPPOSED TO SAID SUBSTRATE;
Claim 2
Dependent Claim
51 words
A PROCESS FOR MAKING A BI-DIRECTIONAL SOLID STATE DEVICE, COMPRISING: FORMING AN OXIDE LAYER ON EACH SURFACE OF A SUBSTRATE WAFER OF ONE SEMICONDUCTOR TYPE; PHOTOENGRAVING SIMULTANEOUSLY ON BOTH SIDES OF SAID WAFER TO DEFINE ALIGNED BASE REGIONS; SIMULTANEOUSLY DIFFUSING BASE REGIONS TO HAVE A SEMICONDUCTOR TYPE OPPOSED TO SAID SUBSTRATE;
Claim 3
Dependent Claim
91 words
A process for making a bi-directional solid state device, comprising: forming an oxide layer on each surface of a substrate wafer of one semiconductor type; photoengraving simultaneously on both sides of said wafer to define aligned base regions; simultaneously diffusing base regions to have a semiconductor type opposed to said substrate; photoengraving simultaneously on both sides of said wafer to define aligned emitter regions in said base regions; simultaneously diffusing emitter regions to have a semiconductor type the same as said substrate; forming electrical contacts to said base and emitter regions.
Claim 4
Dependent Claim
91 words
A process for making a bi-directional solid state device, comprising: forming an oxide layer on each surface of a substrate wafer of one semiconductor type; photoengraving simultaneously on both sides of said wafer to define aligned base regions; simultaneously diffusing base regions to have a semiconductor type opposed to said substrate; photoengraving simultaneously on both sides of said wafer to define aligned emitter regions in said base regions; simultaneously diffusing emitter regions to have a semiconductor type the same as said substrate; forming electrical contacts to said base and emitter regions.
Claim 5
Dependent Claim
46 words
A process as claimed in claim 1, including, simultaneously forming a passivation layer on each side of the wafer after diffusing the emitter regions and before forming said electrical contacts; and photoengraving simultaneously on both sides of the wafer to open contact regions through passivation layers.
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) | 1978-12-22 | 1979-06-23 | 1979-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-22 | 1983-06-23 | 1983-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-22 | 1987-06-23 | 1987-12-23 | $7700.00 | Window Closed / Lapsed |