Method of manufacturing semiconductor device

1. A method for manufacturing a semiconductor device, the method comprising:

preparing a semiconductor substrate constituted of a group III nitride semiconductor and including a p-type body region, a main surface of the semiconductor substrate being a c-plane;

forming a groove on the main surface by dry-etching the main surface; and

wet-etching an inner surface of the groove using an etchant to expose the c-plane including the body region in a wet-etched region, the etchant having an etching rate to the c-plane of the semiconductor substrate that is lower than the etching rate to a plane other than the c-plane of the semiconductor substrate;

forming an n-type source region and an n-type drain region in the semiconductor substrate such that the c-plane exposed by the wet etching includes the source region and the drain region, and the body region is located between the source region and the drain region on the c-plane exposed by the wet etching; and

forming a gate electrode at a position facing an area between the source region and the drain region of the c-plane exposed by the wet etching.

2. The method of claim 1 , wherein

the forming of the source region and the drain region comprises forming at least one of the source region and the drain region at a position of a bottom surface of the groove.

3. The method of claim 2 , wherein

the forming of the groove on the main surface comprises forming a first groove and a second groove on the main surface, and

the forming of the source region and the drain region comprises forming the source region at a position of a bottom surface of the first groove and forming the drain region at a position of a bottom surface of the second groove.