Semiconductor device and a method of manufacturing the same

Abstract

A semiconductor device and a method of manufacturing such a semiconductor device having a field effect transistor with improved current driving performance (e.g., an increase of drain current) of the field effect transistor comprising the steps of ion implanting an element from the main surface to the inside of a silicon layer as a semiconductor substrate to a level shallower than the implantation depth of the impurities in the step of forming the semiconductor region before the step of ion implanting impurities from the main surface to the inside of the silicon layer as a semiconductor substrate to form the semiconductor region being aligned with the gate electrode.

1 . A method of manufacturing a semiconductor device including a field effect transistor comprising the steps of:
 forming a semiconductor film on a main surface of a semiconductor substrate;   ion implanting impurities for reducing a resistance value to the semiconductor film;   patterning the semiconductor film to form a gate electrode;   ion implanting an element of a group identical with that of the semiconductor film to the semiconductor film,   ion implanting the element to the region aligned with the gate electrode of the main surface of the semiconductor substrate; and   ion implanting the impurities to the region aligned with the gate electrode.   
   
   
       2 . A method of manufacturing a semiconductor device according to  claim 1 , further comprising a step of:
 activating the impurities by a heat treatment after the step of ion implanting the impurities,   wherein the step of ion implanting the element of the group identical with that of the semiconductor film is conducted before the step of activating the impurities by the heat treatment.   
   
   
       3 . A method of manufacturing a semiconductor device according to  claim 1 , further comprising a step of:
 activating the impurities by a heat treatment after the step of ion implanting the impurities,   wherein the step of ion implanting the element of the group identical with that of the semiconductor film is conducted before the step of ion implanting the impurities.   
   
   
       4 . A method of manufacturing a semiconductor device according to  claim 1 ,
 wherein the semiconductor film is comprised of silicon and the element is comprised of Ge ions.   
   
   
       5 . A method of manufacturing a semiconductor device according to  claim 2 , wherein the acceleration energy for the element upon ion implantation to the semiconductor film is higher than the acceleration energy for the element upon ion implantation to the region aligned with the gate electrode. 
   
   
       6 . A method of manufacturing a semiconductor device according to  claim 2 , wherein the amount of dose of the element upon ion implantation to the semiconductor film is larger than the amount of dose of the element upon ion implantation to the region aligned with the gate electrode.