Investigations of 4H‐SiC trench MOSFET with integrated high‐K deep trench and gate dielectric

Abstract This paper proposes and investigates a novel 4H‐SiC trench MOSFET (TMOS) with integrated high‐ K deep trench and gate dielectric (INHK‐TMOS). The integrated high‐ K (INHK) consists of a high‐ K gate dielectric and an extended high‐ K deep trench dielectric in the drift region. Firstly, the high‐ K gate dielectric together with the metal‐forming high‐ K metal gate structure, which increases the gate oxide capacitance ( C OX ), reduces the threshold voltage ( V TH ) and the specific on‐resistance ( R on,sp ). Secondly, the extended high‐ K deep trench dielectric not only modulates the electric field in the drift region by introducing a new electric field peak at the bottom of the high‐ K deep trench dielectric, thereby enhancing the breakdown voltage ( BV ), but also improves the doping concentration ( N D ) of the drift region by the assist depletion effect of the high‐ K dielectric, further optimizing the forward conduction characteristics. Simulation results demonstrate that when compared to the conventional TMOS, the INHK‐TMOS using HfO 2 exhibits a 52.6% reduction in V TH , a 52.1% reduction in R on,sp , a 20.3% increasement in BV and a 202.3% improvement in figure of merit.