Semiconductor device and mehtod of manufacturing the same

Abstract

A semiconductor device is proposed which includes: a semiconductor substrate of a first conductivity type; a channel region formed at a surface of the semiconductor substrate; source and drain regions of a second conductivity type formed at both sides of the channel region in the semiconductor substrate; an insulating layer covering the channel region; and a gate electrode formed on the insulating layer, the insulating layer containing impurity atoms in such a manner that a concentration thereof is non-uniformly distributed along a surface parallel to the semiconductor substrate.

What is claimed is:  
     
         1 . A semiconductor device comprising: 
 a semiconductor substrate of a first conductivity type;    a channel region formed at a surface of the semiconductor substrate;    source and drain regions of a second conductivity type formed at both sides of the channel region in the semiconductor substrate;    an insulating layer covering the channel region; and    a gate electrode formed on the insulating layer,    the insulating layer containing impurity atoms in such a manner that a concentration thereof is non-uniformly distributed along a surface parallel to the semiconductor substrate.    
     
     
         2 . The semiconductor device according to  claim 1 , wherein the impurity atoms are selected from the group consisting of B, C, N, F, P, S, Cl, As, Se, and Br.  
     
     
         3 . The semiconductor device according to  claim 1 , wherein a highest concentration of the impurity atoms is equal to or a lowest concentration thereof or twice as large as the lowest concentration thereof.  
     
     
         4 . The semiconductor device according to  claim 1 , wherein a highest concentration of the impurity atom is equal to or more than 10 19  cm −3 .  
     
     
         5 . A method of manufacturing a semiconductor device comprising: 
 forming an insulating layer on a semiconductor substrate of a first conductivity type;    forming a conductive layer on the insulating layer;    forming on the conductive layer a spotted layer including minute spots containing a resistive material resisting against ion implantation;    non-uniformly implanting impurity ions to the conductive layer via the spotted layer containing the resistive material; and    diffusing the impurity ions in the conductive layer into the insulating layer.    
     
     
         6 . The method of manufacturing a semiconductor device according to  claim 5 , wherein the impurity ions are selected from the group consisting of B, C, N, F, P, S, Cl, As, Se and Br.  
     
     
         7 . The method of manufacturing a semiconductor device according to  claim 5 , wherein the resistive material is a resist.  
     
     
         8 . The method of manufacturing a semiconductor device according to  claim 6 , wherein the spotted layer is formed by applying the resist to the conductive layer, and spottedly leaving the resist on the conductive layer by performing etch back of the resist.  
     
     
         9 . The method of manufacturing a semiconductor device according to  claim 5 , further comprising: 
 forming a gate oxide layer from the insulating layer; and    forming a gate electrode from the conductive layer.    
     
     
         10 . A method of manufacturing a semiconductor substrate comprising: 
 forming an insulating layer on a semiconductor substrate of a first conductivity type;    forming a conductive layer on the insulating layer;    performing implantation of impurity ions several times so that an impurity concentration of the conductive layer becomes non-uniform due to implantation fluctuations; and    diffusing the impurity ions in the conductive layer into the insulating layer.    
     
     
         11 . A method of manufacturing a semiconductor substrate comprising: 
 forming an insulating layer on a semiconductor substrate of a first conductivity type;    forming a conductive layer on the insulating layer;    forming minute concavity and convexity on a surface of the conductive layer by etching the conductive layer;    performing ion implantation of impurity ions on the conductive layer having the concavity and convexity on the surface; and    diffusing the impurity ions in the conductive layer into the insulating layer.    
     
     
         12 . The method of manufacturing a semiconductor substrate according to  claim 11 , wherein the etching is chemical dry etching.  
     
     
         13 . The method of manufacturing a semiconductor substrate according to  claim 11 , wherein the etching is wet etching.  
     
     
         14 . The method of manufacturing a semiconductor device according to  claim 12 , wherein said impurity ions are selected from the group consisting of B, C, N, F, P, S, Cl, As, Se and Br.  
     
     
         15 . The method of manufacturing a semiconductor device according to  claim 13 , wherein said impurity ions are selected from the group consisting of B, C, N, F, P, S, Cl, As, Se and Br.  
     
     
         16 . The method of manufacturing a semiconductor device according to  claim 14 , further comprising: 
 forming a gate oxide layer from the insulating layer; and    forming a gate electrode from the conductive layer.    
     
     
         17 . The method of manufacturing a semiconductor device according to  claim 15 , further comprising: 
 forming a gate oxide layer from the insulating layer; and    forming a gate electrode from the conductive layer.