Patent US3626542A successfully refreshed from Google Patents.
Patent US2577530A successfully refreshed from Google Patents.
Patent US4502087A successfully refreshed from Google Patents.
EP0076106A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method for producing a bipolar transistor
Assignee: Fujitsu Ltd
•
Filing: 1982-09-23
•
Granted: —
•
Expires: 2002-09-23
Abstract
Abstract A method for producing a bipolar transistor which has no emitter-base short and which attains a high density for an integrated circuit comprises the steps of forming a polycrystalline silicon layer (10) on an anti-oxidation masking layer (8) placed on a base region (9), selectively etching the silicon layer (10) to form an opening (11), introducing impurities into the base region (9) to form an emitter region (17), converting the polycrystalline silicon layer (10) into an oxide layer (19) whereby the size of the opening (11) is reduced, selectively etching the anti-oxidation masking layer to form an emitter electrode opening (20), and forming electrodes (23, 24, 25).
Inventors
- 👤 Tadashi Kiriseko
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 06:59
CPC Classifications
H; H10; H10P; H10P76/00; H10P76/40; H10D; H10D48/00; H10D48/30; H10D48/32; H10D48/34; H10D48/345; H10P95/00; Y; Y10; Y10S; Y10S438/00; Y10S438/942
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
149 words
A method for producing a bipolar transistor in which a base region (9) is formed in a semiconductor body, an emitter region (17) is formed in the base region, and electrodes (23,24,25) and conductor lines are formed, characterised by the steps of forming a semiconductor layer (10) on an anti-oxidation masking layer (8) placed on the base region (9); selectively etching the semiconductor layer (10) to form a first opening (11) for defining an emitter region and a second opening (12) for a base electrode; introducing impurities into the base region (9) through the first opening (11) to form the emitter region (17); converting the semiconductor layer (10) into an oxide layer (19); selectively etching the anti-oxidation masking layer (6) by using the oxide layer (19) as a mask to form an emitter electrode opening (20) and a base electrode opening (21); and forming electrodes (23,24,25) and conductor lines.
Claim 2
Independent Claim
149 words
A method for producing a bipolar transistor in which a base region (9) is formed in a semiconductor body, an emitter region (17) is formed in the base region, and electrodes (23,24,25) and conductor lines are formed, characterised by the steps of forming a semiconductor layer (10) on an anti-oxidation masking layer (8) placed on the base region (9); selectively etching the semiconductor layer (10) to form a first opening (11) for defining an emitter region and a second opening (12) for a base electrode; introducing impurities into the base region (9) through the first opening (11) to form the emitter region (17); converting the semiconductor layer (10) into an oxide layer (19); selectively etching the anti-oxidation masking layer (6) by using the oxide layer (19) as a mask to form an emitter electrode opening (20) and a base electrode opening (21); and forming electrodes (23,24,25) and conductor lines.
Claim 3
Dependent Claim
24 words
A method according to Claim 1, characterised in that the semiconductor body (1) comprises a semiconductor substrate (2) and an epitaxial layer (3) thereon.
Claim 4
Dependent Claim
19 words
A method according to Claim 1 or Claim 2, characterised in that the semiconductor layer (10) comprises polycrystalline silicon.
Claim 5
Independent Claim
35 words
A method according to any preceding claim, characterised in that the anti-oxidation masking layer (8) is formed by depositing silicon nitride on the surface of the base region (9) by a chemical vapour deposition process.
Claim 6
Independent Claim
31 words
A method according to any preceding claim, characterised in that the anti-oxidation masking layer (8) is formed by thermally nitriding the surface of the base region (9) of the semiconductor body.
Claim 7
Independent Claim
30 words
A method according to any preceding claim, characterised in that in the converting step the semiconductor layer (10) is thermally oxidized to form the oxide layer (19) of silicon dioxide.
Claim 8
Dependent Claim
12 words
A bipolar transistor produced by a method according to any preceding claim.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.