EP0153686A2
Expired / Lapsed
EP
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Method for making transistor
Assignee: Panasonic Holdings Corp
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Filing: 1985-02-18
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Granted: —
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Expires: 2005-02-18
Abstract
Abstract Manufacturing of a graft-base transistor is characterized by: first, forming a layer (8) of oxide of silicon with opening on an n-semiconductor layer (2). at a part to become a base region (3, 4, 3) (FIG. 2(a)): then, forming a polycrystalline silicon layer (9) and an overriding silicon nitride layer (10) with an opening (11) thereon (FIG. 2(b)); selectively diffusing P or As to form an n-emitter region (5) (FIG. 2(c)); forming a second silicon oxide layers (12.13) only on the emitter region (5) and on peripheral regions thereabout, and removing the polycrystalline layer (9) and the silicon nitride layer (10), (FIG. 2(d)) (FIG. 2(e)); and implanting B + ions, thereby to form deeper and higher concentration base contact regions (3, 3) and shallower and lower concentration active base region (4).
Inventors
- 👤 Tetsuo Toyooka
- 👤 Masatoshi Shiraishi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 11:12
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/01; H10D10/051; H10D10/056; H10D62/00; H10D62/10; H10D62/17; H10D62/177; Y; Y10; Y10S; Y10S148/00; Y10S148/01; Y10S148/151
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
210 words
Method for making transistor comprising the steps of: selectively forming a first layer (8) of oxide of silicon on a principal face of a semiconductor layer (2+1) of a first conductivity type to become a collector region, except on a part to become a base region, (3,4,3) forming a layer (9) of polycrystalline silicon and thereon a layer of silicon nitride both on all surface of said principal face, selectively removing said layer of polycrystalline silicon and said layer of silicon nitride, at the part to form an emitter region, thereby to form an opening, selectively diffusing an impurity to form an emitter through said opening (11), thereby to form an emitter region (5), forming a second layer (12) of oxide of silicon on a surface of said emitter region (5), selectively oxidizing said layer (9) of polycrystalline silicon in lateral direction underneath said layer (10) of silicon nitride to form walls (13,13) of oxide of said polycrystalline silicon around said opening (11), removing said layer (10) of silicon nitride and said layer (9) of polycrystalline silicon, and ion implanting another impurity to form a base (P) ion implanting another impurity to form a base through said principal surface into said semiconductor layer (2+1) thereby forming a base region (3).
Claim 2
Dependent Claim
210 words
Method for making transistor comprising the steps of: selectively forming a first layer (8) of oxide of silicon on a principal face of a semiconductor layer (2+1) of a first conductivity type to become a collector region, except on a part to become a base region, (3,4,3) forming a layer (9) of polycrystalline silicon and thereon a layer of silicon nitride both on all surface of said principal face, selectively removing said layer of polycrystalline silicon and said layer of silicon nitride, at the part to form an emitter region, thereby to form an opening, selectively diffusing an impurity to form an emitter through said opening (11), thereby to form an emitter region (5), forming a second layer (12) of oxide of silicon on a surface of said emitter region (5), selectively oxidizing said layer (9) of polycrystalline silicon in lateral direction underneath said layer (10) of silicon nitride to form walls (13,13) of oxide of said polycrystalline silicon around said opening (11), removing said layer (10) of silicon nitride and said layer (9) of polycrystalline silicon, and ion implanting another impurity to form a base (P) ion implanting another impurity to form a base through said principal surface into said semiconductor layer (2+1) thereby forming a base region (3).
Claim 3
Dependent Claim
66 words
Method for making transistor in accordance with claim 1, wherein said semiconductor layer (2+1) comprises a silicon sub- strate (1) and an epitaxial layer (2) of a first conductivity type formed thereon, said an impurity to form the emitter is of said first conductivity type, said another impurity to form the base is of a second conductivity type which is opposite to said first conductivity type,
Claim 4
Dependent Claim
23 words
Method for making transistor in accordance with claim 2, wherein said first conductivity type is n-type and said second conductivity type is p-type.
Claim 5
Dependent Claim
23 words
Method for making transistor in accordance with claim 3, wherein said an impurity is P or As and said another impurity is B.
Claim 6
Dependent Claim
58 words
Method for making transistor in accordance with claim 1, 2, 3 or 4, wherein said base region (3) is formed to comprise a shallower and lower concentration region (4) due to masking by said second layer (12) of oxide of silicon and said walls (13,13) of oxide of said polycrystalline semiconductor, and deeper and higher concentration regions (33).
References Cited (Backward Citations)
No citation records indexed.
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