Semiconductor device, semiconductor device fabrication method, and electronic device

Abstract

A semiconductor device includes a source electrode and a drain electrode located over a surface of a semiconductor layer including an electron transit layer and an electron supply layer. A gate electrode is located between the source electrode and the drain electrode. A first diamond layer is located between the source electrode and the drain electrode over the surface with an insulating film therebetween. A second diamond layer is located directly on the surface between the gate electrode and the drain electrode. Of heat generated by the semiconductor layer of the semiconductor device in operation, heat on the side of the electrode on which a relatively strong electric field is applied is efficiently transferred to the second diamond layer. The semiconductor device achieves an excellent heat dissipation property from the semiconductor layer and effectively suppresses overheating and a failure and degradation of the characteristics due to the overheating.

What is claimed is: 
     
         1 . A semiconductor device fabrication method comprising:
 a process for forming a source electrode and a drain electrode apart from each other over a first surface of a semiconductor layer;   a process for forming a first insulating film over a first region of the first surface, among a plurality of regions including the first region of the first surface on a side of the source electrode between the source electrode and the drain electrode, a second region of the first surface on a side of the drain electrode between the source electrode and the drain electrode, and a third region of the first surface between the first region and the second region between the source electrode and the drain electrode;   a process for forming a diamond layer having an opening corresponding to the third region over a second surface of the first insulating film opposite to the first surface and over the second region, the diamond layer being in contact with the second region; and   a process for forming a gate electrode in the opening.   
     
     
         2 . The semiconductor device fabrication method according to  claim 1 , wherein:
 the semiconductor layer has a concave portion formed in the second region; and   the first surface includes an inside of the concave portion.   
     
     
         3 . The semiconductor device fabrication method according to  claim 1 , further comprising:
 a process for forming a second insulating film over the third region,   wherein:   the opening is formed so as to reach the second insulating film; and   the gate electrode is formed in the opening which reaches the second insulating film.