Patent ID: 9368940
Filing Date: 2016-06-14
CPC Classification: H01S

Claim Text:
1. A semiconductor device comprising: a substrate; a first nitride semiconductor layer arranged over a major plane of the substrate; a second nitride semiconductor layer arranged over the first nitride semiconductor layer; a third nitride semiconductor layer arranged over the second nitride semiconductor layer: a fourth nitride semiconductor layer arranged between the first nitride semiconductor layer and the second nitride semiconductor layer; and a side face at which the second nitride semiconductor layer is exposed, wherein the side face extends in a first direction, wherein the fourth nitride semiconductor layer is arranged being retracted from the side face, in second areas on both sides of a first area extending in a second direction that intersects the first direction, wherein a band gap of the first nitride semiconductor layer, which is a first conductive type, is larger than that of the second nitride semiconductor layer, wherein a band gap of the third nitride semiconductor layer, which is a second conductive type that is a opposite conductive type of the first conductive type, is larger than that of the second nitride semiconductor layer; wherein a band gap of the fourth nitride semiconductor layer, which contains Al, is larger than that of the third nitride semiconductor layer; wherein the major plane of the substrate has an off-angle in a <1-100> direction from a (0001) plane, and wherein a layer thickness of a third area from the side face of the second nitride semiconductor layer up to an end part of the fourth nitride semiconductor layer is smaller than a layer thickness of the first area.