Patent ID: 8058688
Filing Date: 2011-11-15
Classification: H01L

Abstract:
1. A semiconductor device comprising: a semiconductor substrate; a first semiconductor layer of a first conductivity type provided on a major surface of the semiconductor substrate and having lower doping concentration than the semiconductor substrate; a plurality of first semiconductor column regions of the first conductivity type provided on the first semiconductor layer; a plurality of second semiconductor column regions of a second conductivity type provided on the first semiconductor layer, the second semiconductor column regions being adjacent to the first semiconductor column regions; a first semiconductor region of the second conductivity type provided on the second semiconductor column region; a second semiconductor region of the first conductivity type selectively provided in a surface of the first semiconductor region; a gate insulating film extending from the second semiconductor region via the first semiconductor region onto the first semiconductor column region; a first main electrode provided on a surface of the semiconductor substrate, the surface being on the opposite side of the major surface; a second main electrode provided on the second semiconductor region; and a control electrode provided on the gate insulating film configured to control a current path between the second main electrode and the first semiconductor column regions, doping concentrations in both the first and second semiconductor column region being low on the near side of the first semiconductor layer and high on the second main electrode side, and doping concentration at a bottom of the first semiconductor column region and doping concentration at a bottom of the second semiconductor column region being higher than doping concentration in the first semiconductor layer.