a second conductive type first source and {HEAD ~ a second conductive type drain}, which are formed beneath the upper surface at two sides of the first gate respectively, wherein the drain and the first source are separated by {TAIL ~ the first gate} and the first field oxide region from to view, and the drain is formed in the high voltage well 
a second conductive type first source and { HEAD ~ a second conductive type drain } , which are formed beneath the upper surface at two sides of the first gate respectively , wherein the drain and the first source are separated by { TAIL ~ the first gate } and the first field oxide region from to view , and the drain is formed in the high voltage well
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH