Semiconductor device and method for manufacturing semiconductor device

Abstract

A semiconductor device of the present invention includes: a III-V nitride semiconductor layer including a channel region in which carriers travel; a concave portion provided in an upper portion of the channel region in the III-V nitride semiconductor layer; and a Schottky electrode consisting of a conductive material forming a Schottky junction with the semiconductor layer, and formed on a semiconductor layer, which spreads over the concave portion and peripheral portions of the concave portion, on the III-V nitride semiconductor layer. A dimension of the concave portion in a depth direction is set so that a portion of the Schottky electrode provided in the concave portion can adjust a quantity of the carriers traveling in the channel region.

1 - 28 . (canceled) 
   
   
       29 . A field effect transistor comprising:
 a channel layer made of a group III nitride semiconductor layer;   a first electron supply layer formed on the channel layer and made of Al u Ga 1-u N (0≦u≦1) different from a material of the channel layer;   a second electron supply layer formed on the first electron supply layer and made of Al V Ga 1-V N (0≦v≦1, u≠v);   a gate electrode formed on a concave portion formed in the second electron supply layer to reach the first electron supply layer, the gate electrode spreading over peripheral portions of the concave portion and coming into contact with the first electron supply layer; and   a source electrode and a drain electrode formed on the second electron supply layer.   
   
   
       30 . The field effect transistor of  claim 29 , wherein
 a dimension of an opening of the concave portion is decreasing in a direction toward the first electron supply layer.   
   
   
       31 . The field effect transistor of  claim 29 , wherein
 the gate electrode is formed to fill the concave portion and a width of part of the gate electrode above the second electron supply layer is decreasing in a direction away from the second electron supply layer.   
   
   
       32 . The field effect transistor of  claim 29 , further comprising
 a protection layer formed on the second electron supply layer,   wherein part of the gate electrode spreading over the peripheral portions of the concave portion is formed on the protection layer.