Patent ID: 8581367

Claim:
A semiconductor device comprising: a substrate made of a conducting material and having a first main face having a rectangular shape with a center; a first electrode provided at the center on the first main face of the substrate, the first electrode is made of conducting material harder than the substrate; and a second electrode provided along at least a part of the periphery on the first main face so as to surround the first electrode, wherein the second electrode has a thinner film thickness than a film thickness of the first electrode and directly contacts the first main face of the substrate, and the second electrode is formed to be indented in a direction which faces to the substrate relative to the first electrode, and the second electrode is flush with the substrate in a lengthwise direction of the substrate; and a third electrode in contact with a second main face of the substrate opposed to the first main face, wherein a semiconductor element for flowing principal current between the first electrode and the third electrode is provided on the substrate, wherein a combination of the first electrode and the second electrode is in contact over an entire area on the first main face of the substrate, the first electrode and the second electrode are cathode electrodes, wherein the first electrode and the second electrode are ohmic-contacted with the substrate, and the third electrode is Schottky-contacted with the substrate, and wherein material of each of the first electrode and the second electrode is harder than that of third electrode.