Semiconductor device and method for fabricating same

Abstract

An aspect of the present invention includes; a silicon oxynitride film having an oxynitride layer which is formed on at least the surface of a silicon substrate and in which nitrogen atoms are in a three-coordinate bond state, and a silicon oxide layer which is formed between said oxynitride layer and said silicon substrate.

What is claimed is:  
     
         1 . A semiconductor device comprising a silicon oxynitride film having an oxynitride layer which is formed on at least the surface of a silicon substrate and in which nitrogen atoms are in a three-coordinate bond state, and a silicon oxide layer which is formed between said oxynitride layer and said silicon substrate.  
     
     
         2 . The semiconductor device a set forth in  claim 1 , wherein the amount of fixed charges of said silicon oxynitride film is 2.0×10 11  cm −2  or less.  
     
     
         3 . The semiconductor device as set forth in  claim 1 , wherein said oxynitride layer is a monoatomic layer.  
     
     
         4 . The semiconductor device as set forth in  claim 1 , wherein said oxynitride layer is formed on the uppermost surface of said silicon substrate.  
     
     
         5 . The semiconductor device as set forth in  claim 1 , wherein said silicon oxynitride film is a gate insulating film of a field effect transistor.  
     
     
         6 . A method for fabricating a semiconductor device comprising: 
 forming a layer in which nitrogen atoms are arranged on at least the surface of a silicon substrate;    causing said nitrogen atoms in said layer to be in a three-coordinate bond state with silicon atoms existing on the surface of said silicon substrate; and    forming a silicon oxide layer between said silicon substrate and said layer while holding the bonding state of said nitrogen atoms of three-coordinate bonds in said layer with said silicon atoms.    
     
     
         7 . The method for fabricating a semiconductor device as set forth in  claim 6 , wherein said forming of the layer in which the nitrogen atoms are arranged on the silicon substrate is carried out by allowing said silicon substrate to react with a nitrogen containing gas.  
     
     
         8 . The method for fabricating a semiconductor device as set forth in  claim 7 , wherein said nitrogen containing gas consists of nitrogen atoms or nitrogen molecular radicals.  
     
     
         9 . The method for fabricating a semiconductor device as set forth in  claim 6 , wherein said layer in which the nitrogen atoms are arranged on the silicon substrate is a monoatomic layer.  
     
     
         10 . The method for fabricating a semiconductor device as set forth in  claim 6 , wherein said oxynitride layer is formed on the uppermost surface of said silicon substrate.  
     
     
         11 . The method for fabricating a semiconductor device as set forth in  claim 6 , wherein said causing the nitrogen atoms is carried out by carrying out a heat treatment at a temperature of 600° C. to 950° C.  
     
     
         12 . The method for fabricating a semiconductor device as set forth in  claim 6 , wherein said forming of the layer in which the nitrogen atoms are arranged on at least the surface of the silicon substrate, and said causing step are repeated a plurality of times before forming a silicon oxide layer between said silicon substrate and said layer.  
     
     
         13 . The method for fabricating a semiconductor device as set forth in  claim 6 , which further comprises: 
 forming a gate electrode on said silicon substrate after forming said silicon oxide layer; and    using said gate electrode as a mask to inject impurities into said silicon substrate to form source and drain regions.    
     
     
         14 . The method for fabricating a semiconductor device as set forth in  claim 6 , which further comprises terminating the surface of said silicon substrate with hydrogen before forming said layer in which the nitrogen atoms are arranged on at least the surface of the silicon substrate, and thereafter, raising the temperature of said silicon substrate to completely remove hydrogen.