Semiconductor device

Abstract

A semiconductor device includes a silicon substrate having a protrusion, a gate insulating film formed over an upper surface of the protrusion of the silicon substrate, a gate electrode formed over the gate insulating film, a source/drain region formed in the silicon substrate on the side of the gate electrode, a first side wall formed over the side surface of the protrusion of the silicon substrate, the first side wall containing an insulating material. a second side wall formed over the first side wall, the second side wall having a bottom portion formed below the upper surface of the protrusion of the silicon substrate, the second side wall containing a material having a Young's modulus greater than that of the silicon substrate, and a stress film formed over the gate electrode and the second side wall.

1 . A semiconductor device comprising:
 a silicon substrate including a protrusion;   a gate insulating film over an upper surface of the protrusion of the silicon substrate;   a gate electrode over the gate insulating film;   a source/drain region in the silicon substrate;   a first side wall spacer over the side surface of the protrusion of the silicon substrate, the first side wall spacer including an insulating material;   a second side wall spacer over the first side wall spacer, the second side wall spacer including a bottom portion below the upper surface of the protrusion of the silicon substrate, the second side wall spacer including a material having first Young's modulus greater than second Young's modulus of the silicon substrate; and   a stress film over the gate electrode and the second side wall spacer.   
     
     
         2 . The semiconductor device according to  claim 1 , wherein the first side wall spacer is silicon oxide and the second side wall spacer is silicon nitride. 
     
     
         3 . The semiconductor device according to  claim 1 , wherein the side surface of the protrusion is inclined from the direction perpendicular to the major surface of the silicon substrate. 
     
     
         4 . The semiconductor device according to  claim 1 , wherein the second side wall spacer has a thickness four times greater than or equal to the thickness of the first side wall spacer. 
     
     
         5 . The semiconductor device according to  claim 1 , wherein the inclination of the side surface of the protrusion is in the range of 30 degrees and 60 degrees. 
     
     
         6 . A semiconductor device comprising:
 a silicon substrate including a protrusion;   a gate insulating film over an upper surface of the protrusion of the silicon substrate;   a gate electrode over the gate insulating film;   a source/drain region in the silicon substrate;   a first side wall spacer over the side surface of the protrusion of the silicon substrate, the first side wall spacer including an insulating material;   a second side wall spacer over the first side wall spacer, the second side wall spacer formed by a material having first Young's modulus greater than second Young's modulus of the silicon substrate; and   a stress film over the gate electrode and the second side wall spacer.   
     
     
         7 . The semiconductor device according to  claim 6 , wherein the first side wall spacer is silicon oxide and the second side wall spacer is silicon nitride. 
     
     
         8 . The semiconductor device according to  claim 6 , wherein the side surface of the protrusion is inclined from the direction perpendicular to the major surface of the silicon substrate. 
     
     
         9 . The semiconductor device according to  claim 6 , wherein the second side wall spacer has a thickness four times greater than or equal to the thickness of the first side wall spacer. 
     
     
         10 . The semiconductor device according to  claim 6 , wherein the inclination of the side surface of the protrusion is in the range of 30 degrees and 60 degrees. 
     
     
         11 . A method of manufacturing a semiconductor device, comprising:
 forming a gate insulating film and a gate electrode over a silicon substrate;   implanting first impurities into the silicon substrate using the gate electrode as a mask;   selectively removing the surface of the silicon substrate using the gate electrode as a mask so as to form a protrusion of the silicon substrate, the protrusion having an upper surface and a side surface;   forming a first side wall spacer on the side surface of the protrusion, the first side wall spacer containing an insulating material;   forming a second side wall spacer on the first side wall, the second side wall spacer containing a material having first Young's modulus greater than second Young's modulus of the silicon substrate; and   forming a stress film over the gate electrode and the second side wall spacer.   
     
     
         12 . The method according to  claim 11 , further comprising implanting second impurities into the silicon substrate using the gate electrode, the first side wall spacer and the second side wall spacer as a mask. 
     
     
         13 . The method according to  claim 11 , wherein the forming the first side wall spacer on the side surface of the protrusion, the first side wall spacer including an insulating material and the forming the second side wall spacer on the first side wall spacer, the second side wall spacer including the material are performed by forming a first insulating film on the silicon substrate and the gate electrode, forming a second insulating film on the first insulating film having a Young's Modulus grater than that of the first insulating film, and selectively removing the first and the second insulating film such that at least a part of the first and the second insulating film is remained over the side surface of the protrusion of the silicon substrate. 
     
     
         14 . The method according to  claim 11 , wherein the forming the first side wall spacer on the side surface of the protrusion, the first side wall spacer including an insulating material and the forming the second side wall spacer on the first side wall spacer, the second side wall spacer including the material having a Young's modulus greater than that of the silicon substrate further includes selectively removing the entire surface of the first insulating film such that the height of the surface of the first insulating film is lower than that of the upper surface of the protrusion of the silicon substrate. 
     
     
         15 . The method according to  claim 11 , wherein the first side wall spacer is silicon oxide and the second side wall spacer is silicon nitride. 
     
     
         16 . The method according to  claim 14 , the selectively removing the entire surface of the first insulating film such that the height of the surface of the first insulating film is lower than that of the upper surface of the protrusion of the silicon substrate is performed by anisotropic etching the first insulating film after forming the first insulating film over the silicon substrate.