doping {TAIL ~ first impurity elements} at a first concentration providing n type into the semiconductor layer using {HEAD ~ the gate electrode} as a mask to form a first n type impurity region 
doping { TAIL ~ first impurity elements } at a first concentration providing n type into the semiconductor layer using { HEAD ~ the gate electrode } as a mask to form a first n type impurity region
OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH