Semiconductor device having silicide transistors and non-silicide transistors formed on the same substrate and method for fabricating the same

Abstract

A semiconductor device includes a first MIS transistor of a non-salicide structure and a second MIS transistor of a salicide structure which are both formed on a substrate of silicon. The first MIS transistor includes a first gate electrode of silicon, first sidewalls, a first source and drain, and plasma reaction films grown in a plasma atmosphere to cover the top surfaces of the first gate electrode and first source and drain, wherein the plasma reaction film prevents silicide formation on the first MIS transistor.

1 - 12 . (canceled) 
   
   
       13 . A method for fabricating a semiconductor device, said method comprising the steps of:
 (a) forming a first gate electrode and a second gate electrode made of a silicon film on a substrate of silicon;   (b) forming first sidewalls on both sides of the first gate electrode and forming second sidewalls on both sides of the second gate electrode;   (c) forming first source/drain regions in regions of the substrate located further from the first gate electrode than the first sidewalls and forming second source/drain regions in regions of the substrate located further from the second gate electrode than the second sidewalls;   (d) forming plasma reaction films to cover the respective top surfaces of the first gate electrode and first gate/drain regions; and   (e) after the step (d), forming silicide layers on the respective top surfaces of the second gate electrode and second source/drain regions.   
   
   
       14 . The method of  claim 13 , wherein
 the step (d) includes the steps of   exposing the substrate to plasma, thereby forming the plasma reaction films on the top surfaces of the first gate electrode and first source/drain regions and the top surfaces of the second gate electrode and second source/drain regions, and   selectively removing ones of the plasma reaction films formed on the second gate electrode and the second source/drain regions and allowing the other ones of the plasma reaction films to be left on the top surfaces of the first gate electrode and first source/drain regions.   
   
   
       15 . The method of  claim 13 , wherein
 the step (d) includes the steps of   forming a resist on the substrate to cover the second gate electrode and the second source/drain regions and expose the first gate electrode and the first source/drain regions, and   exposing the substrate on which the resist is formed to plasma, thereby forming the plasma reaction films on the top surfaces of the first gate electrode and first source/drain regions.   
   
   
       16 . The method of  claim 13 , wherein
 in the step (d), the plasma reaction films are formed of a plasma oxide film using oxygen plasma.   
   
   
       17 . The method of  claim 13 , wherein
 in the step (d), the plasma reaction films are formed of a plasma nitride film using nitrogen plasma.   
   
   
       18 . The method of  claim 14 , wherein
 in the step (d), the plasma reaction films are formed using inductively-coupled plasma.