Patent ID: 7893437

Claim:
A semiconductor device, comprising: a semiconductor substrate having a first well; a first source electrode, a common drain electrode, and a first gate insulation layer on the semiconductor substrate; a gate electrode on the first gate insulation layer, the first source electrode and the gate electrode being formed from a same polysilicon layer; a second gate insulation layer on the gate electrode; a first source region on the semiconductor substrate between the first source electrode and the first gate insulation layer; a first drain region on the semiconductor substrate between the common drain electrode and the first gate insulation layer; an insulating layer on the first source electrode, and on the first source region; a second source electrode on the insulating layer over the first source electrode; a second source region between the second source electrode and the second gate insulation layer, wherein the first source electrode and the second source electrode are both located between the first source region and the second source region; a second drain region between the common drain electrode and the second gate insulation layer, wherein the common drain electrode is located between the first drain region and the second drain region; and a second well on the second source region, on the second drain region, on the second source electrode, on the second gate insulation layer, and on the common drain electrode.