Semiconductor device and manufacturing method thereof

摘要

A semiconductor device includes: an n-type first source region and first drain region formed in a surface of a p-type epitaxial layer; an n-type first source drift region and first drain drift region formed so as to individually surround the first source region and the first drain region; and a p-type first diffusion region formed in a first channel region and having a higher concentration than the epitaxial layer, the semiconductor device having p-type first withstand voltage maintaining regions formed between the first diffusion region, and the first source drift region and first drain drift region respectively, the first withstand voltage maintaining regions having a lower concentration than the first diffusion region.

主权项

1. A semiconductor device, comprising:
a semiconductor layer of a first conductive type having selectively formed therein a field effect transistor region; a source region and a drain region of a second conductive type formed in a surface of the semiconductor layer with a gap therebetween in the field effect transistor region; a pair of drift regions of the second conductive type formed with a gap therebetween so as to surround individually the source region and the drain region; a gate electrode formed over the surface of the semiconductor layer across a gate insulating film so as to face a channel region formed in the area between the pair of drift regions; a first diffusion region of the first conductive type formed in the channel region at a gap from at least one of the drift regions, the first diffusion region having a concentration higher than the semiconductor layer; and second diffusion regions of the first conductive type formed directly under at least the drift regions and having a concentration higher than the semiconductor layer, wherein, between the first diffusion region and said at least one of the drift regions, a first withstand voltage maintaining region of the first conductive type is present, the first withstand voltage maintaining region having a concentration lower than the first diffusion region.