Method for manufacturing semiconductor device, and semiconductor device

Abstract

The present invention provides a technique for efficiently forming a high-breakdown voltage transistor and a low-breakdown voltage transistor on the same substrate while reducing the deterioration of each transistors' characteristics. At first, an insulating film is formed. The insulating film portions above the drain and source formation regions for the high-breakdown voltage transistor are thicker than those for the low-breakdown voltage transistor. Next, gates are formed on the insulating film. Then sidewalls are formed on the sides of the low-breakdown voltage transistor gate, and apertures are made in the insulating film portions above the drain and source formation regions for each transistor. When apertures are made in the relatively thick insulating film portions above the drain and source formation regions for the high-breakdown voltage transistor, etching is performed not to narrow widths of the sidewalls formed on the sides of the gate for the low-breakdown voltage transistor. Then drain and source regions are formed for each transistor by introduction of impure elements through the apertures.

1 . A method of manufacturing a semiconductor device comprising: 
 forming a first transistor including:    a first gate insulating film;    a first gate electrode formed on the first gate insulating film; and    a first sidewall formed on a side of the first gate electrode, and forming a second transistor including:    a second gate insulating film that includes a first portion and a second portion being thinner than the first portion;    a second gate electrode formed on the first portion of the second gate insulating film; and    a second sidewall formed on a side of the second gate electrode.    
   
   
       2 . The method according to  claim 1 , 
 the first sidewall including a first different material from the first gate insulating film; and    the second sidewall including a second different material from the second gate insulating film.    
   
   
       3 . The method according to  claim 1 , 
 the first sidewall and the second sidewall including silicon nitride.    
   
   
       4 . The method according to  claim 1 , further comprising forming a film on the second sidewall.  
   
   
       5 . The method according to  claim 4 , 
 the film having a curved shape.    
   
   
       6 . The method according to  claim 5 , 
 the film being formed on a portion of the second gate electrode.    
   
   
       7 . The method according to  claim 6 , 
 the film being formed on the second portion of the second gate insulating film.