Patent ID: 9368609
Filing Date: 2016-06-14
CPC Classification: H01L

Claim Text:
1. A semiconductor device comprising: a first nitride semiconductor layer formed above a substrate; a second nitride semiconductor layer formed over the first nitride semiconductor layer and having a band gap larger than that of the first nitride semiconductor layer; a trench passing through the second nitride semiconductor layer as far as a midway of the first nitride semiconductor layer; and a gate electrode disposed by way of a gate insulation film in an inside of the trench, wherein a corner of the trench between a side wall of the trench and a bottom of the trench comprises a chamfered shape, and a corner of the gate insulation film in contact with the corner of the trench comprises a chamfered shape, and wherein the corner of the trench comprises a first tapered portion and a second tapered portion situated below the first tapered portion, and an angle formed between the second tapered portion and the bottom of the trench is smaller than an angle formed between the first tapered portion and the bottom of the trench.