Patent ID: 7388256
Filing Date: 2008-06-17
Classification: H01L

Abstract:
1. A semiconductor device, comprising a laterally diffused field effect transistor which includes: (a) a semiconductor layer of a first conductive type formed over a semiconductor substrate; (b) a gate insulating film formed over the semiconductor layer; (c) a gate electrode formed over the gate insulating film; (d) a source comprised of a first semiconductor region of a second conductive type which is different from the first conductive type; (e) a drain comprised of a second semiconductor region of the second conductive type having a first impurity concentration, and a third semiconductor region of the second conductive type having a higher second impurity concentration than the first impurity concentration and being formed at a position further from the gate electrode than the second semiconductor region; (f) a fourth semiconductor region of the first conductive type where a channel region is formed; (g) a sixth semiconductor region of the first conductive type formed in the semiconductor layer and being a region for connecting electrically the first semiconductor region and the semiconductor substrate to each other; and (h) a trench formed between the first semiconductor region and the sixth semiconductor region so as to extend from the front surface of the semiconductor layer toward the semiconductor substrate, wherein an insulating film is embedded in the trench.