摘要 |
A semiconductor device includes a high voltage first conduction type well in a semiconductor substrate, a second conduction type body in the high voltage first conduction type well, a source region in the second conduction type body, a trench in the high voltage first conduction type well, a first isolation oxide, an impurity doped polysilicon film, and a second isolation oxide stacked in the trench in succession, a drain region in the high voltage first conduction type well on one side of the trench, and a polygate on and/or over the high voltage first conduction type well. |