Patent ID: 7859052

Claim:
A semiconductor apparatus comprising: a first first-conductivity-type semiconductor layer; a second first-conductivity-type semiconductor layer provided on a major surface of the first first-conductivity-type semiconductor layer; a third second-conductivity-type semiconductor layer being adjacent to the second first-conductivity-type semiconductor layer, provided on the major surface of the first first-conductivity-type semiconductor layer, and forming a periodic array structure in combination with the second first-conductivity-type semiconductor layer in a lateral direction generally parallel to the major surface of the first first-conductivity-type semiconductor layer; a first main electrode electrically connected to the first first-conductivity-type semiconductor layer; a fourth second-conductivity-type semiconductor region provided on the third second-conductivity-type semiconductor layer; a fifth first-conductivity-type semiconductor region selectively provided in a surface of the fourth second-conductivity-type semiconductor region; a second main electrode provided in contact with the fifth first-conductivity-type semiconductor region and the fourth second-conductivity-type semiconductor region; a control electrode provided on the fifth first-conductivity-type semiconductor region, the fourth second-conductivity-type semiconductor region, and the second first-conductivity-type semiconductor layer via an insulating film; and a sixth first-conductivity-type semiconductor layer provided on the major surface of the first first-conductivity-type semiconductor layer in a termination section outside the periodic array structure of the second first-conductivity-type semiconductor layer and the third second-conductivity-type semiconductor layer, the second first-conductivity-type semiconductor layer having an impurity concentration varying in the lateral direction, the impurity concentration being minimized at a center in the lateral direction, an impurity concentration in the sixth first-conductivity-type semiconductor layer being not higher than the impurity concentration at the center of the second first-conductivity-type semiconductor layer, and the second first-conductivity-type semiconductor layer having lower ends of regions with a higher impurity concentration sandwiching the third second-conductivity-type semiconductor layer and being formed to extend below the major surface of the first first-conductivity-type semiconductor layer.