| 摘要 |
PURPOSE:To improve the operation speed of a transistor, by partially oxidizing only the surface of a polysilicon layer for taking out a base around an emitter forming window, insulating a base electrode and an emitter electrode, thereby decreasing the resistance value of a base taking out electrode. CONSTITUTION:An opening part is formed in an insulating film 9 on the main surface of a substrate 1 in an element forming region 10, in which base regions 13a and 13b and an emitter region 19 are formed on the main surface of the semiconductor substrate 1. Impurities are introduced through the opening part, and a semiconductor region, which is to become the outer base region 13a, is formed. A semiconductor layer 14, which is to become a base taking out electrode 14a, if formed on the region. Heat treatment is performed. Two regions having different selection raios are formed on the semiconductor layer 14. Then, an emitter forming window 16 is formed by etching. With an insulating film 23 as a mask, the semiconductor layer 14 at the periphery of the emitter forming window 16 is partially oxidized. Thereafter, the insulating film 9 on the main surface of the substrate at the inner side of the emitter forming window 16 is selectively removed. Impurities are introduced through the opening part 16, and a semiconductor region, which is to become the intrinsic base region 13b, is formed. A semiconductor region, which is to become the emitter region 19, is formed in the inside of said region. |
