| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of mask processes and heat treatment processes in the manufacture of a high dielectric strength bipolar transistor. SOLUTION: By forming a PSG layer on a substrate, a protective film on a region in which a depletion layer is spread, a protective film for the protection from external contamination can be formed simply, and phosphorus treatment and formation of an emitter region can be practiced simultaneously. The reasonable low cost operation, for instance only four mask processes are required, can be realized, therefore, in the manufacture of a high dielectric strength semiconductor device.
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