SEMICONDUCTOR SUBSTRATE AND MANUFACTURING METHOD THEREOF, AND SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor device and its manufacturing method and a semiconductor substrate and its manufacturing method, capable of bidirectionally keeping the breakdown voltage and high in reliability. SOLUTION: A N-type silicon substrate 1 has a bottom face and an upper face facing each other. A high-concentration P-type impurity diffusion layer 3 is formed over the whole surface by the diffusion of the P-type impurity in the bottom face of the N-type silicon substrate 1. A P-type isolation region 2 is formed in part by the diffusion of the P-type impurity in the upper face of the N-type silicon substrate 1. The P-type isolation region 2 has the bottom face, reaching the upper face of the P-type impurity diffusion layer 3. When viewed from the upper face side of the N-type silicon substrate 1, the P-type isolation region 2 is formed to surround N-region 1a, which is a part of the N-type silicon substrate 1. The N-region 1a surrounded by the P-type isolation region 2 is specified as an element forming region of the N-type silicon substrate 1. COPYRIGHT: (C)2004,JPO