Semiconductor device and method for manufacturing the same

A method for manufacturing a semiconductor device, comprising the steps of:

• forming an insulating film on a semiconductor layer that is formed on a semi-insulating semiconductor substrate and includes an active layer;
• forming a first resist film having a first opening part on the surface of the insulating film;
• removing the insulating film by using the first resist film as a mask and forming a tapered recess area whose sidewall is inclined on the surface of the semiconductor layer;
• forming a through hole which has a tapered shape, in which the sidewall is inclined at an angle smaller than the angle of inclination of the sidewall of the recess area by using the first resist film as a mask on the insulating film;
• forming a second resist layer having a second opening part, which entirely exposes the through hole, on the surface of the insulating film;
• and
• vapor-depositing a metal by using the second resist film as a mask so as to fill the recess area and the through hole with the metal.

A semiconductor device, comprising:

• a semiconductor layer that is formed on a semiconductor substrate and includes an active layer having a recess area with inclined sidewalls;
• an insulating film that is formed on the semiconductor layer and has a through hole with inclined sidewalls that are inclined at an angle smaller than the angle of inclination of the inclined sidewalls of the recess area;
• a drain electrode and a source electrode formed on opposite sides of the recess area on the semiconductor layer;
• and
• a gate electrode formed so as to fill the recess area and the through hole and to protrude above the levels of the drain electrode and the source electrode, the upper surface of the gate electrode having a downward concave shape.