US3753807A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of bipolar semiconductor devices
Assignee: Nortel Networks Technology Corp
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Filing: 1972-02-24
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Granted: 1973-08-21
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Expires: 1992-02-24
Abstract
Abstract A method of making bipolar semiconductors in which the base contact regions and the emitter region are defined by one masking step. A layer of polycrystalline silicon is formed on a substrate, the polycrystalline layer being removed at the positions for the base contact regions and the emitter produced beneath the remaining part of the layer by diffusion from the polycrystalline silicon which has been doped with a suitable emitter region dopant.
Inventors
- 👤 R Hoare
- 👤 Quhae K Mc
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:00
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/17; H10D62/177; H10D99/00; H10P; H10P32/00; H10P32/10; H10P32/14; H10P32/1408; H10P32/1414; H10P32/17; H10P32/171; H10P95/00; Y; Y10; Y10S; Y10S148/00; Y10S148/053; Y10S148/055; Y10S148/106; Y10S148/111; Y10S148/122; Y10S148/124; Y10S148/143; Y10S148/145
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
21 words
A method as claimed in claim 1, including doping the polycrystalline silicion layer with a dopant suitable for an emitter region.
Claim 2
Dependent Claim
27 words
A method as claimed in claim 2, including heating the device to diffuse the dopant in the polycrystalline layer into the substrate to form the emitter region.
Claim 3
Dependent Claim
63 words
A method as claimed in claim 1 including: forming a layer of silicon nitride over the polycrystalline silicon layer after forming the polycrystalline layer; masking the silicon nitride layer; and etching the silicon nitride layer to expose the polycrystalline silicon layer at areas coincident with the eventual base contact regions; whereby the silicon nitride layer acts as the mask for the polycrystalline layer.
Claim 4
Dependent Claim
37 words
A method as claimed in claim 4, including: edge etching the polycrystalline layer after etching the polycrystalline layer down to the substrate, to undercut the silicon nitride layer and to define the size of the emitter region.
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) | 1976-08-20 | 1977-02-19 | 1977-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-20 | 1981-02-19 | 1981-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-20 | 1985-02-19 | 1985-08-21 | $7700.00 | Window Closed / Lapsed |