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 semiconductor device comprising: 
 a first transistor including:    a first gate insulating film;    a first gate electrode formed on the first gate insulating film; and    a first film formed on a side of the first gate electrode, the first film having a first curved shape, and    a second transistor including:    a second gate insulating film;    a second gate electrode on the second gate insulating film;    a second film, the second film formed on a side of the second gate electrode, the second film having a second curved shape; and    a third film formed on the second film, the third film having a third curved shape.    
   
   
       2 . The semiconductor device according to  claim 1 , 
 the first film including a first different material from the first gate insulating film; and    the second film including a second different material from the second gate insulating film.    
   
   
       3 . The semiconductor device according to  claim 1 , 
 the first film and the second film including silicon nitride.    
   
   
       4 . The semiconductor device according to  claim 1 , 
 the second gate insulating film including a first portion and a second portion being thinner than the first portion.    
   
   
       5 . The semiconductor device according to  claim 1 , 
 the first gate insulating film being thinner than the second gate insulating film.    
   
   
       6 . The semiconductor device according to  claim 1 , 
 the first transistor having a first break down voltage; and    the second transistor having a second break down voltage that is higher than the first break down voltage.