Semiconductor device and manufacturing method of the same

Abstract

A semiconductor device capable of improving the driving power and a manufacturing method therefor are provided. In a semiconductor device, a gate structure formed by successively stacking a gate oxide film and a silicon layer is arranged over a semiconductor substrate. An oxide film is arranged long the lateral side of the gate structure and another oxide film is arranged along the lateral side of the oxide film and the upper surface of the substrate. In the side wall oxide film comprising these oxide films, the minimum value of the thickness of the first layer along the lateral side of the gate structure is less than the thickness of the second layer along the upper surface of the substrate.

1 . A semiconductor device comprising:
 a gate structure arranged over a semiconductor substrate;   side walls arranged on both lateral sides of the gate structure; and   a stress liner film arranged so as to cover the gate structure and the side wall,   wherein the side wall has an oxide film with an L-cross sectional shape having a first layer along the lateral side of the gate structure and a second layer along the upper surface of the semiconductor substrate, and   wherein the minimum value of the thickness of the first layer is less than the thickness of the second layer.   
     
     
         2 . A semiconductor device according to  claim 1 , wherein the side wall further has a nitride film arranged over the second layer. 
     
     
         3 . A semiconductor device according to  claim 2 , wherein the nitride film comprises a rectangular parallelepiped body in which each of the bottoms thereof is less than the height thereof. 
     
     
         4 . A semiconductor device according to  claim 3 , wherein the height for the nitride film is 10 nm or less. 
     
     
         5 . A semiconductor device according to  claim 2 , wherein the nitride film is arranged in the region for an SPAM, but not arranged in the region for a logic. 
     
     
         6 . A semiconductor device according to  claim 1 , further including a silicide layer arranged over the gate structure and the semiconductor substrate. 
     
     
         7 . A semiconductor device according to  claim 6 , further including an oxide film arranged over the semiconductor substrate at outside of the side wall. 
     
     
         8 . A manufacturing method of a semiconductor device comprising the steps of:
 forming a gate structure over a semiconductor substrate;   forming side walls on both lateral sides of the gate structure; and   forming a stress liner film so as to cover the gate structure and the side wall,   wherein the side wall forming step includes the steps of:   forming a first oxide film along the lateral side of the gate structure, a second oxide film in an L-cross sectional shape along the lateral side of the first oxide film and the upper surface of the semiconductor substrate, and a nitride film along the second oxide film respectively; and   etching the first oxide film, the second oxide film, and the nitride film with a hot phosphoric acid, and   wherein the second oxide film is removed more than the first oxide film in the etching step.   
     
     
         9 . A manufacturing method of a semiconductor device according to  claim 8 , wherein the first oxide film is formed of TEOS and the second oxide film is formed of USG in the side wall forming step. 
     
     
         10 . A manufacturing method of a semiconductor device according to  claim 8 , wherein the side wall forming step further includes the steps of:
 etching the semiconductor substrate at the surface of a region excepting just below the gate structure; and   forming a silicide layer over the gate structure and the semiconductor substrate.   
     
     
         11 . A semiconductor device according to  claim 2 , further including a silicide layer arranged over the gate structure and the semiconductor substrate. 
     
     
         12 . A semiconductor device according to  claim 11 , further including an oxide film arranged over the semiconductor substrate at outside of the side wall.