Patent ID: 7135718

Claim:
A diode device, comprising: a semiconductor layer of a first conductivity type having a plurality of holes, said holes including ring-shaped holes and main holes provided in an inner circumference of the ring-shaped holes; a filler made of a semiconductor of a second conductivity type filled within said holes; and an electrode film of a material forming a Schottky junction with said semiconductor layer and an ohmic junction with said filler, wherein: among said ring-shaped holes, concentrically provided ring-shaped holes and the filler filled within these holes form a plurality of guard ring portions, the main holes provided in the inner circumference of the innermost ring-shaped holes and the filler filled within these main holes form withstanding voltage portions, said electrode film is at least in contact with a surface of the semiconductor layer positioned in the inner circumference of the ring of the innermost guard ring portion and a surface of the filler in the withstanding voltage portions, a relay diffusion layer of the second conductivity type in a depth shallower than a bottom of the ring-shaped holes formed at the surface within the semiconductor layer positioned between said guard ring portions, said relay diffusion layer is not in contact with at least one of the two guard ring portions adjacent to each other and the relay diffusion layer is held at floating potential, depth of the plurality of holes are set equal, intervals between the guard ring portions are set equal, and a total amount of a first conductivity type impurity and a total amount of a second conductivity type impurity positioned on the inner side of a central line of any one of the guard ring portions are set equal, and a region of the second conductivity type impurity positioned within the inner circumference of the outermost guard ring portion is depleted, when the semiconductor layer of the first conductivity type positioned on the inner side of the outermost guard ring portion is depleted.