Modeling of gallium oxide vertical transistors for high power applications

Abstract

Ultra-wide bandgap semiconductors, such as gallium oxide (Ga2O3), have gained considerable interest in recent years due to their extremely wide bandgap >(4 eV), high breakdown strength ( 8 MV cm--1), and satisfactory electron mobility (200-250 cm2/V s). This interest stems from its potential application in high-power electronic devices across various domains, including electric vehicles, high-performance computing, and green energy technologies. However, one significant challenge in harnessing Ga2O3 for power applications has been associated with the lack of stable p-type doping. This limitation is effectively addressed by fin field-effect transistor (FinFET) structures, designed on an n-type substrate, eliminating the need for p-type doping. Vertical Ga2O3 power devices promise efficient carrier movement and fast operational speed, overcoming short-channel effects in ultra-high-density integrated circuits. This research work aims to cover two main areas of vertical Ga2O3 device modeling: physics-based analytical modeling, and device simulation using numerical simulators. An extensive physics-based surface potential model has been formulated in this study for a vertical Ga2O3 FinFET. In addition, the investigation utilizes statistical analysis using the Monte Carlo simulation technique to study the changes in leakage current in Ga2O3 FinFET. Furthermore, this study proposes a current-voltage and a capacitance-voltage model as a function of surface potential. The verification of the analytical model with experimental data, along with the incorporation of numerical simulators (TCAD), confirms the importance and potential of the proposed models in rapidly creating and characterizing next-generation high-performance vertical Ga2O3 power transistors.