Vertical field effect transistor having a high withstand voltage

摘要

It is intended to provide a high withstand voltage vertical field effect type semiconductor device that relaxes electric fields in a semiconductor substrate without thickening thickness of a drift region and achieves withstand-ability against high voltage without sacrificing ON-voltage, switch-OFF characteristics, and miniaturization. A field effect type semiconductor device comprises emitter regions (100,104) and gate electrodes (106) and the like on a surface (upper surface in FIG.2), a collector region (101) and the like on the other surface (lo - -type field dispersion regions (111) of low impurity concentration are arranged between P-type body regions (103) facing to gate electrodes (106) and an N-type drift region (102) below P-type body regions (103). Thereby, the electric field between collector and emitter is relaxed and a high withstand voltage field effect type semiconductor device is realized. Another field dispersion region can be arranged between the N-type drift region (102) and P + -type collector region (101) below the N-type drift region (102).