| 摘要 |
PURPOSE:To remarkably shorten a distance between an emitter region and a high concentration base region by forming a low concentration base region of a graft base structure in width equal to the emitter width determined by a normal mask pattern accuracy, forming the high concentration base region in contact with the low concentration base region, and further forming the emitter region in the low concentration base region. CONSTITUTION:Silicon nitride films 7, 9 and a silicon oxide film 8 which cover the surface of a part to be formed with a graft base P<++> type region, i.e., a high concentration base region are removed to expose a silicon substrate surface, and a P-type impurity is ion implanted to this part to form a low resistance P<++> type region 10. Further, after a base region part 13 under an emitter is formed, a polycrystalline silicon film 14 containing arsenic As of an N-type impurity is formed on the surface, the film 14 is further formed in a predetermined pattern, As in the polycrystalline silicon is diffused by thermal diffusion to form an N<+> type emitter region 15.
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