SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREFOR, POWER CONVERSION DEVICE, THREE-PHASE MOTOR SYSTEM, VEHICLE, AND RAILWAY VEHICLE

摘要

To provide a power semiconductor device having high performance and high reliability.SOLUTION: A semiconductor device includes: a first conductivity type semiconductor substrate; a drain electrode formed on the rear surface side of the semiconductor substrate; a first conductivity type drift layer formed on the semiconductor substrate; a second conductivity type body layer; a first conductivity type JFET region interposed between body layers; a first conductivity type source region that is connected to a source electrode and is formed in the body layer; a first conductivity type first current diffusion layer that is connected to the source region and has a concentration lower than that of the source region; a second conductivity type first electric field relaxation layer formed on the first current diffusion layer; a first conductivity type second current diffusion layer that is connected to the JFET region and has a concentration equal to that of the first current diffusion layer; a second conductivity type second electric field relaxation layer formed on the second current diffusion layer; a trench that extends to the first current diffusion layer, the first electric field relaxation layer, the body layer, the second current diffusion layer, and the second electric field relaxation layer, is located at a position shallower than that of the body layer, and has a bottom surface in contact with the body layer; a gate insulation film formed on an inner wall of the trench; and a gate electrode formed on the gate insulation film.SELECTED DRAWING: Figure 2