Semiconductor device

A semiconductor device comprising:

• a semiconductor substrate comprising a first semiconductor region of a first conductivity type;
• an active region in the semiconductor substrate;
• a breakdown withstanding region outside the active region;
• a collector region of a second conductivity type on a back surface of the semiconductor substrate;
• a second semiconductor region of the second conductivity type in a peripheral area of the breakdown withstanding region, the second semiconductor region being formed through the semiconductor substrate from a front surface thereof to the back surface thereof, the second semiconductor region being in contact with the collector region;
• a third semiconductor region of the second conductivity type in a surface portion of the breakdown withstanding region on a front side of the semiconductor substrate, the third semiconductor region surrounding the active region;
• an interlayer insulator film formed selectively on the front surface of the semiconductor substrate;
• a plurality of electrically conductive film portions in contact with the third semiconductor region, the plurality of electrically conductive film portions being on the interlayer insulator film;
• one or more of the plurality of the electrically conductive film portions, excluding at least an electrically conductive film portion in contact with a farthest third semiconductor region, which a depletion layer extending from the second semiconductor region toward the active region reaches, the farthest third semiconductor region being spaced apart most widely from the second semiconductor region, comprising a second semiconductor region side edge portion projecting farther toward the second semiconductor region than a second semiconductor region side edge portion of the third semiconductor regions in contact with the respective one or more of the plurality of electrically conductive film portions;
• a fourth semiconductor region of the second conductivity type in a surface portion of the breakdown withstanding region on the front side of the semiconductor substrate, the fourth semiconductor region suppressing an expansion of the depletion layer extending from the second semiconductor region toward the active region at a reverse voltage application;
• and
• the one or more of the plurality of electrically conductive film portions, in contact with the third semiconductor regions between the second semiconductor region and the fourth semiconductor region and excluding at least the electrically conductive film portion in contact with the farthest third semiconductor region, which the depletion layer extending from the second semiconductor region toward the fourth semiconductor region reaches, the farthest third semiconductor region being spaced apart most widely from the second semiconductor region, comprising a second semiconductor region side edge portion projecting farther toward the second semiconductor region than the second semiconductor region side edge portion of the third semiconductor regions in contact with respective one or more of the plurality of electrically conductive film portions.