Semiconductor device and fabrication method therefor

摘要

A high withstand voltage well is formed on a surface of a semiconductor substrate. A drain region and a source region of a high withstand voltage transistor included in an input protection circuit are formed on the high withstand voltage well. A p-type impurity region is formed adjacent to the lower portion of the drain region of the high withstand voltage transistor. The p-type impurity region is fabricated in the same fabrication step as a low withstand voltage well formed in a region on which a low withstand voltage transistor is formed.