Method of inhibiting degradation of gate oxide film

Abstract

A method of inhibiting degradation of a transistor gate oxide film by high density plasma is disclosed. After a gate electrode is formed, impurity is injected on the surface of an interlayer insulating film, thereby changing surface characteristics of the interlayer insulating film to scatter ultraviolet rays which are factors of degradation of the interlayer insulating film. Accordingly, the ultraviolet rays are prevented from being permeated into a gate insulating oxide film.

1 . A method for manufacturing a semiconductor device, comprising the steps of: 
 forming a gate oxide film and a gate electrode on a semiconductor substrate;    forming an interlayer oxide film on the semiconductor substrate including the gate electrode;    injecting an impurity into a surface of the interlayer oxide film to form a layer for preventing UV (Ultraviolet rays) generated by high density plasma from penetrating the interlayer oxide film; and    forming a HDP oxide film on the interlayer oxide film.    
   
   
       2 . (canceled)  
   
   
       3 . The method according to  claim 1 , wherein the impurity is selected from a group consisting of As, P, B, BF 2 , BF, Si and Ge.  
   
   
       4 . The method according to  claim 1 , wherein a concentration of the impurity ranges from 1 e 17 /cm 3  to 1 e 22 /cm 3 .  
   
   
       5 . (canceled)  
   
   
       6 . The method according to  claim 1 , wherein the step of injecting the impurity is performed immediately after the formation of the interlayer oxide film or prior to the formation of the HDP oxide film.  
   
   
       7 . The method according to  claim 1 , wherein the impurity is injected to a depth of less than 1000 Å.