Fishing – trapping – and vermin destroying
Patent
1991-05-23
1992-02-25
Chaudhuri, Olik
Fishing, trapping, and vermin destroying
437 26, 437 32, 357 34, H01L 21265, H01L 2973
Patent
active
050913239
ABSTRACT:
In a process for the fabrication of a bipolar semiconductor device having a substrate, the substrate defining a working surface, and a collector region of a first conductivity type formed within the substrate at a position adjacent to the working surface, a patterned, oxidation-resistant film is formed on a predetermined portion of the collector region. A silicon oxide film region is formed within the collector region at a position spaced downwardly from an exposed surface of the collector region. A selective epitaxial layer of a second conductivity type is formed so that the selected epitaxial layer extends from the exposed surface of the collector region to a portion of a top part of the patterned, oxidation-resistant film. A portion of the patterned, oxidation-resistant film, the portion being free of the selective epitaxial layer, is removed to expose the collector region. A base region of the second conductivity type is formed so that the base region extends from the thus-exposed surface of the collector region to the silicon oxide film region. An emitter region of the first conductivity type is then formed within the base region at a position adjacent to the exposed surface of the collector region.
REFERENCES:
patent: 4706378 (1987-11-01), Havemann
patent: 4783422 (1988-11-01), Kawkatsu
patent: 4810664 (1989-03-01), Kamins et al.
Chaudhuri Olik
OKI Electric Industry Co., Ltd.
Pham Long
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