Modeling and Analysis of Gallium Oxide Vertical Transistors

Gallium oxide (Ga₂O₃) based semiconductor devices are expected to disrupt power electronic applications in the near future. Due to the wide bandgap of Ga₂O₃, it should be possible to fabricate power devices with higher breakdown voltages and lower on-state resistances compared to incumbent Silicon (Si) and Silicon Carbide (SiC) technologies. In particular, vertical metal-oxide field effect transistor (MOSFETs) and vertical Fin Field Effect Transistor (FinFETs) devices based on Ga₂O₃ have been recently reported. Here, we present a comparative modelling study of such vertical Ga₂O₃ power transistors using use Technology Computer Aided Design (TCAD) and analyze their electro-thermal performance under static and dynamic operating conditions. We find that the MOSFETs show a trade-off between the current gains and threshold voltages, as a function of device geometry and acceptor concentrations in the body region. In contrast, in the FinFETs structures it is possible to achieve normally-off operation by proper design of the fin width and its donor concentration, without p-type doping. Overall, the modeling and analysis results presented here can be used as a guide for experimental improvement of the vertical Ga₂O₃ device performance for future power electronic applications.