| 摘要 |
A P type semiconductor substrate includes a P type body region, an N type drift region formed away from the P type body region in a direction parallel to a substrate surface, an N type drain region formed in a region separated by a field oxide film in the N type drift region so as to have a concentration higher than the N type drift region, an N type source region formed in the P type body region so as to have a concentration higher than the N type drift region. A P type buried diffusion region having a concentration higher than the N type drift region is formed of a plurality of parts each of which is connected to a part of the bottom surface of the P type body region and extends parallel to the substrate surface and its tip end reaches the inside of the drift region. |
