A novel split-gate trench MOSFET embedded with a high-k pillar for higher breakdown voltage

Abstract A novel split-gate trench MOSFET embedded with a high- k pillar (HKP SGT-MOS) is proposed in this study. Numerous electric displacement lines are allowed to enter the high- k pillar introduced beneath the split gate, thus relieving the crowding of the electric field at the bottom corner of the split gate. Therefore, the HKP SGT-MOS can achieve a higher breakdown voltage (BV) without sacrificing its forward conduction. Various dielectrics for the high- k pillar, such as SiO 2 , Si 3 N 4 , Al 2 O 3 and HfO 2 , are investigated. The results reveal that HfO 2 has the largest figure of merit (FOM) and BV. The characteristics of the HKP SGT-MOS have also been validated by the Technology Computer-Aided Design simulation, and the BV and (FOM = BV 2 / R on,sp ) are 258.3 V and 37.46 MW cm −2 , achieving 36.7% and 87.02% improvement compared to the conventional SGT-MOS (CSGT-MOS), and 18.4% and 38.59% improvement compared to the SGT-MOS with short split-gate (SSGT-MOS). Moreover, the influence of the drift doping concentration, the mesa width, the length of the drift region and the width of the split gate/high- k pillar are also studied to optimize the proposed HKP SGT-MOS.