SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To improve the withstand voltage of an MOS field effect transistor in an SOI substrate of which the Si layer is thin. SOLUTION: The N type channel MOS field effect transistor has a source electrode 201, and a drain electrode 202 and a gate electrode 302 with a field oxide film 204 interlaid, on the SOI substrate 101, and has a gate oxide film 301, a high-concentration P type layer 401, a high-concentration N type layer 402 in contact with the source electrode and the gate oxide film, a high- concentration N type layer 403 in contact with the drain electrode and a P type layer (p-body layer) 404 in contact with the high-concentration P type layer, the high-concentration N type layer and the gate oxide film. Herein a region corresponding to 95% or less of a distance 610 between the end of the field oxide film being in contact with the high-concentration N type layer in contact with the drain electrode and the ends of the gate electrode and a gate insulating film is occupied by an N type layer 501 being in contact with the p-body layer and having a higher concentration than a drain region. Besides, an N type region of which the concentration in the vicinity of a buried oxide film under the drain electrode is 3×10<16> -1×10<22> /cm<3> is provided.