Silicon carbide semiconductor device

A silicon carbide semiconductor device, comprising:

• a semiconductor substrate containing silicon carbide and having a first main surface and a second main surface opposite to each other;
• a first semiconductor region of a first conductivity type, provided in the semiconductor substrate;
• a plurality of second semiconductor regions of a second conductivity type, provided in the semiconductor substrate, between the first main surface of the semiconductor substrate and the first semiconductor region;
• a plurality of third semiconductor regions of the first conductivity type, provided in the semiconductor substrate, between the first main surface of the semiconductor substrate and the plurality of second semiconductor regions;
• a plurality of fourth semiconductor regions of the first conductivity type, each provided in the semiconductor substrate between one of the plurality of second semiconductor regions and one of the plurality of third semiconductor regions, and adjacent to the one of the plurality of third semiconductor regions in a depth direction, the plurality of fourth semiconductor regions having an impurity concentration lower than that of the plurality of third semiconductor regions;
• a plurality of trenches penetrating the plurality of third semiconductor regions, the plurality of fourth semiconductor regions, and the plurality of second semiconductor regions;
• a plurality of gate insulating films provided along inner walls of the plurality of trenches, respectively;
• a plurality of gate electrodes respectively provided on the plurality of gate insulating films in the plurality of trenches;
• a plurality of fifth semiconductor regions of the second conductivity type, each provided in the semiconductor substrate between
• one of the plurality of gate insulating films at the inner wall of one of the plurality of trenches,
• and
• one of the plurality of third semiconductor regions and one of the plurality of fourth semiconductor regions through both of which said one of the plurality of trenches penetrates,
• said each fifth semiconductor region being adjacent to said one of the plurality of third semiconductor regions, said one of the plurality of fourth semiconductor regions, and said one of the plurality of gate insulating films;
• a plurality of first electrodes electrically connected to the plurality of third semiconductor regions, the plurality of fourth semiconductor regions, and the plurality of second semiconductor regions;
• and
• a second electrode provided on the second main surface of the semiconductor substrate.