Abstract. An ESOA of LDMOS device is very critical for power device performance. Kirk effect is the one of the major problem which leads to poor ESOA performance. The cause of the problem mainly due to the high beta value of parasitic NPN transistor in the p-body. In this study, we proposed a new 3D high side SideIsolated N-Channel LDMOS which we have obtained not only benchmark Ron and breakdown performance, but also better ESOA without Kirk effect. We have compared the analysis of Kirk effect between the new device and the conventional N-LDMOS structure with LATID technique for the formation of the p-body of both device structures.