Design and Analysis of High‐Performance Schottky Barrier β‐Ga₂O₃ MOSFET With Enhanced Drain Current, Breakdown Voltage, and PFOM

Abstract

In this article, a Schottky barrier β‐Ga2O3 MOSFET is proposed. It shows improvements in drain saturation current, Ion/Ioff ratio, transconductance, and off‐state breakdown voltage. The proposed design, which implements the Schottky barrier source and drain contacts, has led to reduced on‐state resistance (Ron), reduced forward voltage drops, faster switching speed, higher frequency, and improved efficiency. After device optimization, we determined that a source and drain having a work function of 3.90 eV result in the highest drain saturation current of (Ids) 264 mA. Additionally, in the transfer characteristics, we demonstrate that increasing the channel doping concentration led to a shift toward depletion mode operation, while decreasing the doping concentration moved the device toward enhancement mode at the cost of drain current. Analysis of lattice temperature and self‐heating effects on different substrates has also been performed. Furthermore, introducing a passivation layer of SiO2 as a gate oxide and an unintentionally doped (UID) layer of 400 nm doping concentration of 1.5 × 1015 cm−3, results in further significant improvements in the drain saturation current (Ids) of 624 mA and transconductance of 38.09 mS, approximately doubling their values compared with the device without a passivation layer of SiO2 and an Ion/Ioff ratio of 1015, and the device's performance at various substrate temperatures has been evaluated. In addition, the inclusion of a passivation layer of SiO2 improves the breakdown voltage to 2385 V, which is significantly high compared with the conventional device. Moreover, the lower specific‐on‐resistance Ron,sp of 7.6 mΩ/cm2 and higher breakdown voltage then the high‐power figure of merit (PFOM) (BV2/Ron,sp) of 748 MW/cm2 have been achieved.