| 摘要 |
PURPOSE:To enhance a reverse-direction current-amplification factor by a method wherein a lower separation-region and a buried base region are driven in earlier than the diffusion of an upper separation-region so that the two regions can be formed by diffusion at the low impurity-concentration and in a deep manner. CONSTITUTION:A first and a second buried layers 23a, 23b, an IIL buried base region 29 and a lower separation-region 34 for an upper-and-lower separation region 34 are formed on a P-type semiconductor substrate 21. Then, an upper region 35 on the region and an IIL base extraction region 32 are formed so as to reach each region 34 and the region 29 from the surface of an epitaxial layer 22 during a diffusion process of a base region 26 for an NPN transistor. Then, a collector contact region 28, an IIL collector region 31 and a color region 32 are formed during the diffusion process of an emitter region 27 for the NPN transistor. |
