Semiconductor device and method for manufacturing semiconductor device

Abstract

An object of the technique disclosed in the Description is to provide a semiconductor device that reduces a gate leakage current without degrading its high-frequency characteristic. A semiconductor device relating to the technique disclosed in the Description includes a nitride semiconductor layer, a first insulating film partly disposed on the upper surface of the nitride semiconductor layer, and a gate electrode provided to have a lower surface that is at least partly in contact with the upper surface of the nitride semiconductor layer that is exposed without being covered with the first insulating film. The first insulating film is provided to be in contact with a side surface of the gate electrode. The first insulating film contains a transition metal.

1 . (canceled) 
     
     
         2 . A semiconductor device comprising:
 a nitride semiconductor layer;   a first insulating film partly disposed on an upper surface of the nitride semiconductor layer; and   a gate electrode provided to comprise a lower surface that is at least partly in contact with the upper surface of the nitride semiconductor layer that is exposed without being covered with the first insulating film,   wherein the first insulating film is provided to be in contact with a side surface of the gate electrode,   the first insulating film contains a transition metal, and   the first insulating film contains a 1 wt % or less transition metal.   
     
     
         3 . (canceled) 
     
     
         4 . A semiconductor device comprising:
 a nitride semiconductor layer;   a first insulating film partly disposed on an upper surface of the nitride semiconductor layer; and   a gate electrode provided to comprise a lower surface that is at least partly in contact with the upper surface of the nitride semiconductor layer that is exposed without being covered with the first insulating film,   wherein the first insulating film is provided to be in contact with a side surface of the gate electrode,   the first insulating film contains a transition metal, and
 the first insulating film further contains In. 
   
     
     
         5 .- 8 . (canceled) 
     
     
         9 . A method for manufacturing a semiconductor device, comprising:
 epitaxial-growing a nitride semiconductor layer on a semiconductor substrate;   partly forming a first insulating film on an upper surface of the nitride semiconductor layer;   forming a gate electrode in such a manner that a lower surface of the gate electrode is at least partly in contact with the upper surface of the nitride semiconductor layer that is exposed without being covered with the first insulating film, and in such a manner that a side surface of the gate electrode is in contact with the first insulating film;   adding a transition metal to the first insulating film; and   adding a transition metal to the first insulating film after forming the gate electrode.   
     
     
         10 . (canceled) 
     
     
         11 . A method for manufacturing a semiconductor device, comprising:
 epitaxial-growing a nitride semiconductor layer on a semiconductor substrate;   partly forming a first insulating film on an upper surface of the nitride semiconductor layer;   forming a gate electrode in such a manner that a lower surface of the gate electrode is at least partly in contact with the upper surface of the nitride semiconductor layer that is exposed without being covered with the first insulating film, and in such a manner that a side surface of the gate electrode is in contact with the first insulating film;   adding a transition metal to the first insulating film; and   adding a transition metal to the first insulating film through application of a solution containing a transition metal and through thermal diffusion.   
     
     
         12 .- 13 . (canceled)