Patent ID: 8742534

Claim:
A semiconductor device having a lateral diode, the semiconductor device comprising: a semiconductor substrate including a first conductivity-type semiconductor layer; a first conductivity-type first semiconductor region located in the first conductivity-type semiconductor layer; a first conductivity-type contact region having an impurity concentration greater than an impurity concentration of the first conductivity-type first semiconductor region; a second conductivity-type second semiconductor region located in the first conductivity-type semiconductor layer and separated from the first conductivity-type contact region; a first electrode electrically connected through the first conductivity-type contact region to the first conductivity type first semiconductor region; and a second electrode electrically connected to the second conductivity-type second semiconductor region, wherein one of the first conductivity-type first semiconductor region and the second conductivity-type second semiconductor region is a cathode region, the other of the first conductivity-type first semiconductor region and the second conductivity-type second semiconductor region is an anode region, one of the first electrode and the second electrode is a cathode electrode of the lateral diode, the one of the first electrode and the second electrode being connected to the cathode region, the other of the first electrode and the second electrode is an anode electrode of the lateral diode, the other of the first electrode and the second electrode being connected to the anode region, the second conductivity-type second semiconductor region includes a low impurity concentration portion, a high impurity concentration portion, and an extension portion, the low impurity concentration portion is in contact with the high impurity concentration portion and has an impurity concentration less than an impurity concentration of the high impurity concentration portion, the second electrode forms an ohmic contact with the high impurity concentration portion, the extension portion has an impurity concentration greater than the impurity concentration of the low impurity concentration portion and extends in a thickness direction of the first conductivity-type semiconductor layer, the extension portion extends from a surface of the first conductivity-type semiconductor layer to a predetermined depth of the first conductivity-type semiconductor laver, and the predetermined depth is less than a thickness of the first conductivity-type semiconductor layer.