Method of manufacturing a semiconductor device having improved gate structure, and a semiconductor device manufactured thereby

Abstract

A gate insulating film is formed on a semiconductor substrate, and a gate electrode is formed by deposition of semiconductor material on the gate insulating film. An amorphous layer is then formed along the surface of or inside the gate electrode, and side walls are formed on the gate electrode. Finally, impurities are implanted into the semiconductor substrate by ion implantation while the gate electrode and the side walls are used as masks.

1 . A method of manufacturing a semiconductor device comprising the steps of: 
 forming a gate insulating film on a semiconductor substrate;    forming a gate electrode by deposition of semiconductor material on said gate insulating film;    forming an amorphous layer in said gate electrode;    forming side walls on said gate electrode; and    implanting impurities into said semiconductor substrate by ion implantation while said gate electrode and the side walls are used as masks.    
     
     
         2 . The method of manufacturing a semiconductor device according to  claim 1 , wherein said amorphous layer is formed at least either along the top surface of, along the side surfaces of, or inside said gate electrode.  
     
     
         3 . The method of manufacturing a semiconductor device according to  claim 1 , wherein a semiconductor material layer having a grain size of 0.05 μm or less is formed as said amorphous layer.  
     
     
         4 . The method of manufacturing a semiconductor device according to  claim 1 , wherein a semiconductor material layer having a nitrogen concentration of 1×10 20 -1×10 22  atoms/cm 3  is formed as said amorphous layer.  
     
     
         5 . The method of manufacturing a semiconductor device according to  claim 4 , wherein nitrogen is implanted into said semiconductor substrate by ion implantation.  
     
     
         6 . The method of manufacturing a semiconductor device according to  claim 4 , wherein said nitrogen is mixed into said gate electrode simultaneously with deposition of said gate electrode.  
     
     
         7 . The method of manufacturing a semiconductor device according to  claim 4 , wherein said nitrogen is mixed into said gate electrode by annealing said gate electrode in an atmosphere of nitrogen.  
     
     
         8 . The method of manufacturing a semiconductor device according to  claim 4 , wherein a semiconductor material layer having a nitrogen concentration of 1×10 20 -1×10 22  atoms/cm 3  is formed as said amorphous layer to be formed along the surface of or inside said gate electrode, and a semiconductor material layer having a nitrogen concentration of 1×10 20 -1×10 21  atoms/cm 3  is formed as said amorphous layer to be formed along the side surfaces of said gate electrode.  
     
     
         9 . The method of manufacturing a semiconductor device according to  claim 1 , wherein said amorphous layer is formed by oxidization of the surface of said gate electrode.  
     
     
         10 . The method of manufacturing a semiconductor device according to  claim 1 , wherein, in the process for forming said gate electrode, semiconductor material is deposited, and a metal compound layer including the semiconductor material or a metal layer is further deposited on said semiconductor material.  
     
     
         11 . A method of manufacturing a semiconductor device comprising the steps of: 
 forming a gate insulating film on a semiconductor substrate;    forming a gate electrode so as to comprise a plurality of separated layers by deposition of semiconductor material on said gate insulating film;    forming side walls on said gate electrode; and    implanting impurities into said semiconductor substrate by ion implantation while said gate electrode and the side walls are used as masks.    
     
     
         12 . The method of manufacturing a semiconductor device according to  claim 11 , wherein said gate electrode is formed by forming an insulating film on a deposited semiconductor material, and by depositing additional semiconductor material further on said insulating film.  
     
     
         13 . The method of manufacturing a semiconductor device according to  claim 11 , wherein, in the process for forming said gate electrode, semiconductor material is deposited, and a metal compound layer including said semiconductor material or a metal layer is further deposited on said semiconductor material.  
     
     
         14 . A method of manufacturing a semiconductor device comprising the steps of: 
 forming gate insulating films in respective regions on a semiconductor substrate having different conductivity types;    forming gate electrodes by deposition of semiconductor material on each of said gate insulating films;    forming each of nitrogen-containing layers, which are different in nitrogen concentration from each other, along the surface of and/or inside each of said gate electrodes so as to correspond to the conductivity types of said regions of said semiconductor substrate;    forming side walls on each of said gate electrodes; and    implanting impurities into said semiconductor substrate while said gate electrodes and said side walls are used as masks.    
     
     
         15 . The method of manufacturing a semiconductor device according to  claim 14 , wherein, in the process for forming said gate electrode, semiconductor material is deposited, and a metal compound layer including the semiconductor material or a metal layer is further deposited on said semiconductor material.  
     
     
         16 . A semiconductor device comprising: 
 a semiconductor substrate;    a gate insulating film on said semiconductor substrate;    a gate electrode in which an amorphous layer having a grain size of 0.05 μm or less is formed along the surface of or inside said gate electrode and/or along the side surfaces of said gate electrode; and    a conductive region which is formed in said semiconductor substrate by ion implantation after formation of said amorphous layer.    
     
     
         17 . The semiconductor device according to  claim 16 , wherein a semiconductor material layer having nitrogen mixed therein is provided as said amorphous layer.  
     
     
         18 . The semiconductor device according to  claim 16 , wherein a semiconductor material layer having a nitrogen concentration of 1×10 20 -1×10 22  atoms/cm 3  is provided as said amorphous layer along the surface of or inside said gate electrode, and a semiconductor material layer having a nitrogen concentration of 1×10 20 -1×10 21  atoms/cm 3  is provided as said amorphous layer along the side surfaces of said gate electrode.