| 摘要 |
PURPOSE:To prevent the situation that unnecessary current flows to the substrate and ground sides, by providing a semiconductor region of reverse conductivity type at the collector region on the opposite side of the emitter region. CONSTITUTION:After an N<+> type buried layer 12 is formed on a P<-> substrate 11, an N<-> layer 13 is formed by epitaxial growth. Then, a P<+> region 14 is formed as the element isolation region by diffusion or the like, thus electrically isolating the N<-> layer 13 for every element. A P<+> emitter region 15, the first P<+> collector region 16, the second P<+> collector region 17, and a P<+> region 18 surrounding the collector regions 16 and 17 are formed; finally, an N<+> region 19 is formed so as to surround the P<+> region 18. When a voltage lower than that to the collector region C1 or C2 is made to be impressed on the electrode T, even if a transistor comes into saturated action by the reduction in voltage e.g. between the collector region C2 and the emitter region E, the current from the emitter region 15 flows to the region 18 lower than the potential of the collector region 17 and does not flow to the substrate 11 side.
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