Ga2O3 SEMICONDUCTOR ELEMENT

Abstract

A Ga 2 O 3 -based semiconductor element includes a β-Ga 2 O 3 substrate including a first conductivity type, a first β-Ga 2 O 3 single crystal film formed on the β-Ga 2 O 3 substrate, a second β-Ga 2 O 3 single crystal film including a second conductivity type formed on the first β-Ga 2 O 3 single crystal film, a source electrode formed on the second β-Ga 2 O 3 single crystal film, a drain electrode formed on a surface of the β-Ga 2 O 3 substrate opposite to the first β-Ga 2 O 3 single crystal film, and a gate electrode formed via a gate insulating film in a trench formed in the second β-Ga 2 O 3 single crystal film.

What is claimed is: 
     
         1 . A Ga 2 O 3 -based semiconductor element, comprising:
 a β-Ga 2 O 3  substrate comprising a first conductivity type;   a first β-Ga 2 O 3  single crystal film formed on the β-Ga 2 O 3  substrate;   a second β-Ga 2 O 3  single crystal film comprising a second conductivity type formed on the first β-Ga 2 O 3  single crystal film;   a source electrode formed on the second β-Ga 2 O 3  single crystal film;   a drain electrode formed on a surface of the β-Ga 2 O 3  substrate opposite to the first β-Ga 2 O 3  single crystal film; and   a gate electrode formed via a gate insulating film in a trench formed in the second β-Ga 2 O 3  single crystal film.   
     
     
         2 . The Ga 2 O 3 -based semiconductor element according to  claim 1 , wherein the first β-Ga 2 O 3  single crystal film comprises the first conductivity type. 
     
     
         3 . The Ga 2 O 3 -based semiconductor element according to  claim 2 , wherein the first conductivity type is n-type and the second conductivity type is p-type. 
     
     
         4 . The Ga 2 O 3 -based semiconductor element according to  claim 1 , wherein the trench extends to the first β-Ga 2 O 3  single crystal film. 
     
     
         5 . The Ga 2 O 3 -based semiconductor element according to  claim 4 , wherein a bottom surface of the trench ends above a bottom surface of the first β-Ga 2 O 3  single crystal film. 
     
     
         6 . The Ga 2 O 3 -based semiconductor element according to  claim 5 , wherein the gate insulating film is disposed in the first β-Ga 2 O 3  single crystal film and in the second β-Ga 2 O 3  single crystal film. 
     
     
         7 . The Ga 2 O 3 -based semiconductor element according to  claim 1 , further comprising:
 a contact region disposed in the second β-Ga 2 O 3  single crystal film on both sides of the gate electrode.   
     
     
         8 . The Ga 2 O 3 -based semiconductor element according to  claim 7 , wherein the source electrode is disposed on an upper surface of the contact region. 
     
     
         9 . The Ga 2 O 3 -based semiconductor element according to  claim 8 , wherein the source electrode is further disposed on an upper surface of the gate insulating film. 
     
     
         10 . The Ga 2 O 3 -based semiconductor element according to  claim 1 , wherein the gate insulating film is disposed in the first β-Ga 2 O 3  single crystal film. 
     
     
         11 . The Ga 2 O 3 -based semiconductor element according to  claim 10 , wherein the gate insulating film extends in the second β-Ga 2 O 3  single crystal film to contact a bottom surface of the source electrode. 
     
     
         12 . The Ga 2 O 3 -based semiconductor element according to  claim 1 , wherein the Ga 2 O 3 -based semiconductor element includes a Ga 2 O 3 -based MISFET including a vertical-type semiconductor element in which the source electrode and the drain electrode are arranged respectively on upper and lower sides of the Ga 2 O 3 -based semiconductor element and a current flows in a vertical direction. 
     
     
         13 . The Ga 2 O 3 -based semiconductor element according to  claim 12 , wherein, when a voltage of more than a threshold voltage is applied to the gate electrode, channels are formed in the second single crystal film on both sides of the gate electrode and a current flows from the source electrode to the drain electrode. 
     
     
         14 . The Ga 2 O 3 -based semiconductor element according to  claim 1 , wherein the β-Ga 2 O 3  substrate comprises a main surface which is rotated from 50° to 90° with respect to a (100) plane. 
     
     
         15 . The Ga 2 O 3 -based semiconductor element according to  claim 14 , wherein the first β-Ga 2 O 3  single crystal film is formed on the main surface of the β-Ga 2 O 3  substrate. 
     
     
         16 . A Ga 2 O 3 -based semiconductor element, comprising:
 a β-Ga 2 O 3  substrate comprising a first conductivity type;   a first β-Ga 2 O 3  single crystal film comprising the first conductivity type formed on a main surface of the β-Ga 2 O 3  substrate;   a second β-Ga 2 O 3  single crystal film comprising a second conductivity type formed on the first β-Ga 2 O 3  single crystal film;   a source electrode formed on the second β-Ga 2 O 3  single crystal film;   a drain electrode formed on a surface of the β-Ga 2 O 3  substrate opposite to the first β-Ga 2 O 3  single crystal film; and   a gate electrode formed in the first β-Ga 2 O 3  single crystal film and the second β-Ga 2 O 3  single crystal film.   
     
     
         17 . The Ga 2 O 3 -based semiconductor element according to  claim 16 , wherein the gate electrode is covered via a gate insulating film in a trench that extends in the first β-Ga 2 O 3  single crystal film and the second β-Ga 2 O 3  single crystal film. 
     
     
         18 . The Ga 2 O 3 -based semiconductor element according to  claim 17 , further comprising:
 a contact region disposed in the second β-Ga 2 O 3  single crystal film on both sides of the gate electrode.   
     
     
         19 . The Ga 2 O 3 -based semiconductor element according to  claim 18 , wherein the source electrode is disposed on an upper surface of the contact region and on an upper surface of the gate insulating film. 
     
     
         20 . The Ga 2 O 3 -based semiconductor element according to  claim 16 , wherein the main surface of the β-Ga 2 O 3  substrate is rotated from 50° to 90° with respect to a (100) plane.