| 摘要 |
PURPOSE:To improve the characteristics of a bipolar transistor, by forming a surface, to which the base electrode of the bipolar transistor is connected, in a staircase shape. CONSTITUTION:A surface 16, to which a polysilicon electrode 10 of a base is connected, is formed in a staircase shape. A high impurity concentration part in a base region is made shallow. Since the p<+> type base lead-out region 16 becomes shallow, it is sufficiently separated from an n<+> type embedded region 2. The expansion of the p<+> type base lead-out region 16 is made small, and the region is separated from an n<+> emitter region 24. Thus bonding capacitance between them can be decreased. In this way, the base lead-out electrode 10 at the connecting surface between the base lead-out electrode 10 comprising a polycrystalline silicon film and the p<+> type base lead-out region 16 becomes thick. Therefore, the base resistance can be decreased.
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