Semiconductor device with ohmic electrode formed on compound semiconductor having wide band gap and its manufacture method

Abstract

A first film of rare-earth metal is formed on a semiconductor region of compound semiconductor exposed on a substrate. A second film essentially comprising silicon is formed on the surface of the first film. The first and second films are heated to silicidate at least a portion of the first film in contact with the second film. It is possible to lower the contact resistance of an ohmic electrode formed on semiconductor having a wide band gap.

1 - 7 . (canceled)  
   
   
       8 . A semiconductor device comprising: 
 a substrate having a semiconductor region made of compound semiconductor formed in a surface layer of said substrate; and    a first film made of rare-earth metal directly disposed on a surface of the semiconductor region.    
   
   
       9 . A semiconductor device according to  claim 8 , wherein the semiconductor region is made of group III-V compound semiconductor comprising nitrogen as a group V element.  
   
   
       10 . A semiconductor device comprising: 
 a substrate having a semiconductor region made of compound semiconductor formed in a surface layer of said substrate; and    a first film of silicide of rare-earth metal directly disposed on a surface of the semiconductor region.    
   
   
       11 . A semiconductor device according to  claim 10 , wherein the semiconductor region is made of group III-V compound semiconductor comprising nitrogen as a group V element.  
   
   
       12 . A semiconductor device according to  claim 10 , further comprising a second film directly disposed on a surface of said first film and made of metal silicide having a resistivity lower than a resistivity of said first film.  
   
   
       13 . A semiconductor device according to  claim 10 , wherein a silicon concentration of a portion of the semiconductor region in contact with said first film is higher than a silicon concentration of a portion of the semiconductor region remote from said first film.