Novel Superjunction LDMOS With a High-K Dielectric Trench by TCAD Simulation Study

Abstract

A novel superjunction (SJ) lateral double-diffused MOSFET (LDMOS) with a deep High-K(HK) dielectric trench (HK SJ-LDMOS) is proposed and its mechanism is investigated by Technology Computer Aided Design (TCAD) simulations. The HK dielectric trench is embedded under the n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> drain, which is connected with the drain electrode. In the OFF-state, the reshaping effect of HK trench enhances the bulk electric field strength and weakens the peak electric field around the edge of the drain diffusion, which increases the breakdown voltage (BV). Moreover, because of the assistant depletion effect by the HK trench, a lower resistivity substrate is allowed for HK SJ-LDMOS, which also increases the doping concentration of the ntype buffer layer under the SJ layer of HK SJ-LDMOS, correspondingly. Thus, a lower specific ON-resistance (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON,sp</sub> ) is also obtained. Simulation results show that the BV increases by 35.2% in comparison with the conventional buffered SJ-LDMOS with the same drift length. Moreover, HK SJ-LDMOS presents an excellent figure of merit, which is two times higher than that of the conventional buffered SJ-LDMOS.