| 摘要 |
PROBLEM TO BE SOLVED: To form a PNP bipolar transistor excellent in transistor characteristics and an NPN bipolar transistor in the same substrate. SOLUTION: The semiconductor device 60 comprises the PNP type bipolar transistor 66 wherein elements are isolated by an element isolation region 62 and an insulating well region 64, in a p-type substrate 68. The PNP type transistor is a perpendicular type and comprises a p-type emitter region 70, an n-type base region 72, a p-type collector region 74, and a collector electrode leading region 76. Its lower part and its periphery of the p-type collector region are electrically isolated from the substrate by an n-type lower part isolation region 78 and by an n-type circular isolation region 80, respectively. The n-type circular isolation region is formed circularly underneath from the element isolation region, surrounds the periphery of a p-type collector region and the periphery of an upper part of the n-type lower part isolation region, and isolates the p-type collector region electrically from the substrate. Because the n-type isolation region is constituted of the n-type lower part isolation and the n-type cyclic isolation region, the depth position of the n-type lower part isolation can be controlled freely, and therefore the electrical characteristics of a V-PNP can be optimized independently.
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