Semiconductor device and method of manufacturing the same

A method of manufacturing a semiconductor device, comprising:

• forming a dummy gate insulating film on a semiconductor substrate, and forming a dummy gate electrode on the dummy gate insulating film;
• carrying out ion implantation of an impurity into a surface region of the semiconductor substrate by using the dummy gate insulating film and the dummy gate electrode as a mask, and forming an extension region;
• forming a gate sidewall insulating film on side faces of the dummy gate insulating film and the dummy gate electrode;
• doping the impurity into a surface region of the semiconductor substrate by using the dummy gate insulating film, the dummy gate electrode and the gate sidewall insulating film as a mask to form a contact junction region, and forming a source region and a drain region which are constituted of the contact junction region and the extension region;
• forming an interlayer insulating film on the semiconductor substrate so as to cover the dummy gate insulating film, the dummy gate electrode, and the gate sidewall insulating film;
• polishing the interlayer insulating film until a surface of the dummy gate electrode is exposed, and planarizing the surface;
• removing selectively the dummy gate insulating film and the dummy gate electrode to form a gate opening region in the interlayer insulating film;
• forming a recess on the surface region of the semiconductor substrate by oxidizing the surface of the semiconductor substrate which is exposed on a bottom portion of the gate opening region and by removing selectively the oxidized part;
• insulating the surface of the recess in a bottom surface of the gate opening region to form a gate insulating film;
• and
• burying a gate electrode material in the gate opening region to form a gate electrode.