| 摘要 |
The present invention, in a process for manufacturing a semiconductor device, aims to prevent the spread of impurities from a substrate to a semiconductor layer and a lowering in the internal pressure of a transistor. A first conductive-type semiconductor layer (EPI) is formed on a first conductive-type base substrate (BSUB). The concentration of impurities in the semiconductor layer (EPI) is lower than the concentration of impurities in the base substrate (BSUB). A second conductive-type first buried layer (BINPL1) and a second conductive-type second buried layer (BINPL2) are formed on the semiconductor layer (EPI). The second buried layer (BINPL2) is deeper than the first buried layer (BINPL1), is distanced from the first buried layer (BINPL1), and has a lower concentration of impurities than that of the first buried layer (BINPL1). In addition, a transistor (TR1) is formed on the semiconductor layer (EPI). |
