| 摘要 |
PURPOSE:To contrive improvement in controllability of the threshold voltage in a MOS transistor by a method wherein at least a part of the base region of a bipolar transistor and the well region, on which the MOS transistor will be formed, are formed in the same process by selectively introducing impurities. CONSTITUTION:The N<+> (or P<+>) type base region 6-2, which becomes a part of the base of a vertical type P-N-P (or N-P-N) transistor, and the N<+> (or P<+>) type well region 6-1 containing the source and drain region of a P (or N) channel MOS transistor are formed simultaneously from the surface of an N (or P) type epitaxial layer. As a result, the high frequency characteristics and the current characteristics of the emitter earth current amplification factor (hFE) of the vertical type P-N-P (or N-P-N) transistor can be improved, and the controllability of the threshold voltage in the P (or N) channel MOS transistor can also be improved. |
