Semiconductor device and method for producing the same

A method for producing a semiconductor device, comprising:

• forming a locally oxidized region in the upper surface of a semiconductor substrate by resist patterning and etching, wherein the locally oxidized region has a first end and second end connected with a central portion that is thicker than the first and second ends, with the ends shaped progressively thinner away from the central portion;
• forming a gate electrode with a first end on the central portion and on one of the thinner ends of the locally oxidized region, and with a second end on the semiconductor outside the locally oxidized region;
• forming an insulating film on the gate electrode, the locally oxidized region and on the semiconductor outside the locally oxidized region;
• forming a mask on the first end of the gate electrode, and on the second end of the locally oxidized region;
• selectively etching the insulating film using the mask, leaving a portion of the insulating film as a spacer insulating film;
• and
• forming a source region and a drain region in the semiconductor by implanting impurities using the locally oxidized region, the gate electrode, and the spacer insulating film as a mask.