US4590666A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing a bipolar transistor having a reduced base region
Assignee: Fujitsu Ltd
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Filing: 1985-01-31
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Granted: 1986-05-27
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Expires: 2005-01-31
Abstract
Abstract A method of producing a bipolar transistor which includes forming a base region, forming a high-melting-point metal layer of a base electrode on the base region, forming a first insulating layer on the metal layer, and selectively etching the first insulating layer and the metal layer to form an opening. The method further includes forming a second insulating layer on the sides of the first insulating layer and the metal layer within the opening, the second insulating layer defining an emitter-providing region. Impurities are introduced into the base region by using the second insulating layer as a mask to form an emitter region. An emitter electrode and the base electrode are arranged in a similar multilayer structure.
Inventors
- 👤 Hiroshi Goto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:17
CPC Classifications
H; H10; H10D; H10D48/00; H10D48/30; H10D48/32; H10D48/34; H10D48/345; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/20; H10D64/27; H10D64/281; H10P; H10P76/00; H10P76/40; Y; Y10; Y10S; Y10S148/00; Y10S148/01; Y10S148/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
168 words
A method for producing a bipolar transistor having a base region of a first conductivity type comprising the steps of: (a) depositing a high-melting-point metal selected from the group consisting of gold, molybdenum, and tungsten; (b) forming a first insulating layer on the base electrode, the first insulating layer and the base electrode forming a laminated layer; (c) selectively etching the laminated layer to form an opening having sides, in which a portion of the base region is exposed; (d) forming a second insulating layer, having a thickness greater than that of the laminated layer, formed on the laminated layer and the exposed portion of the base region; (e) anisotropically etching the second insulating layer, leaving portions of the second insulating layer along the sides of the opening of the laminated layer; and (f) introducing impurities of a second conductivity type opposite to the first conductivity type, into the base region by using the portions of the second insulating layer as a mask, to form an emitter region.
Claim 2
Independent Claim
168 words
A method for producing a bipolar transistor having a base region of a first conductivity type comprising the steps of: (a) depositing a high-melting-point metal selected from the group consisting of gold, molybdenum, and tungsten; (b) forming a first insulating layer on the base electrode, the first insulating layer and the base electrode forming a laminated layer; (c) selectively etching the laminated layer to form an opening having sides, in which a portion of the base region is exposed; (d) forming a second insulating layer, having a thickness greater than that of the laminated layer, formed on the laminated layer and the exposed portion of the base region; (e) anisotropically etching the second insulating layer, leaving portions of the second insulating layer along the sides of the opening of the laminated layer; and (f) introducing impurities of a second conductivity type opposite to the first conductivity type, into the base region by using the portions of the second insulating layer as a mask, to form an emitter region.
Claim 3
Dependent Claim
38 words
A method for producing a bipolar transistor as set forth in claim 1, wherein said step (d) comprises forming the second insulator from a material selected from the group consisting of phosphosilicate glass, silicon nitride, and aluminum oxide.
Claim 4
Dependent Claim
48 words
A method for producing a bipolar transistor according to claim 1, wherein said step (a) further comprises forming the high-melting-point metal base electrode from a gold layer and a thin alloy layer, formed under the gold layer, the alloy selected from the group consisting of titanium-platinum and titanium-palladium.
Claim 5
Dependent Claim
15 words
A method according to claim 1, wherein said anisotropical etching is a reactive sputter etching.
Claim 6
Dependent Claim
14 words
A method according to claim 1, wherein said anisotropical etching is reactive ion-beam etching.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-26 | 1989-11-25 | 1990-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-26 | 1993-11-25 | 1994-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-26 | 1997-11-25 | 1998-05-27 | $7700.00 | Window Closed / Lapsed |