Semiconductor device with drift layer

Abstract

A semiconductor device includes a semiconductor substrate having a first conductive type impurity, a well having a second conductive type impurity formed in a predetermined region of the semiconductor substrate, a plurality of field oxide layer formed on an upper surface of the semiconductor substrate having the first conductive type impurity and the well having the second conductive type impurity, a gate electrode formed on corresponding portions of the field oxide layer and the well, and a lightly doped first impurity region formed in the well between the gate electrode and the first conductive type impurity region and surrounding the first conductive impurity region from sides and lower portions thereof and relatively lightly doped in comparison to the first conductive type impurity region. The device includes a junction of the lightly doped first impurity region surrounding the first conductive type impurity region is relatively deep in comparison to a junction of the lightly doped first impurity region below the field oxide layer, thereby sufficiently relieving electric field and preventing a hot carrier generation and heightening a junction breakdown voltage.