Nldmos semiconductor device

Abstract

This application provides a semiconductor device. The semiconductor device includes: a substrate () having a first conductivity type; an STI structure () disposed in the substrate () in the form of a first ring-like structure and surrounding a portion of the substrate (), wherein a portion of the substrate surrounded by the STI structure serves as an active area (); a drain doped region () disposed an a top of a central portion of the active area () and having a second conductivity type; source doped regions () having the second conductivity type, wherein the source doped regions are disposed at the top of the active area () on opposite sides of the drain doped region () and are spaced apart from the drain doped region (); a field oxide layer () that is disposed over the top surface of the substrate () within the active area () in the form of a second ring-like structure and surrounds the drain doped region (); gate polysilicon () that is disposed over the top surface of the substrate () and is in the form of a third ring-like structure surrounding the field oxide layer (); and a drift region () having the second conductivity type wherein the drift region is disposed in the substrate () and surrounds the drain doped region ().