Advances in High-Voltage Power Electronics Using Ga₂O₃-Based HEMT: Modeling

Gallium oxide (Ga₂O₃) is a promising ultra-wide-bandgap (UWBG) material with exceptional transport properties, including a large breakdown voltage, making it ideal for high-voltage power device applications. Recently, Ga₂O₃ has gained significant attention as a next-generation material for electronic device fabrication aimed at advancing power electronics. In this paper, we investigate the effect of a Ga₂O₃ buffer layer on a GaN-based high electron mobility transistor (HEMT), focusing on output I-V characteristics and surface charge effects. Furthermore, we explore an advanced approach to enhance HEMT performance by utilizing polarization-induced two-dimensional electron gas (2DEG), as an alternative to conventional doping methods. A III-N/Ga₂O₃ heterostructure is proposed as a distinctive electrical property and a cost-effective UWBG solution. To evaluate the associated effects, we simulate a two-dimensional (2D) Ga₂O₃/GaN HEMT structure incorporating surface charge models. Our results confirm that 2DEG formation near the surface creates a conductive channel due to polarization-induced dipoles at the interface. The simulations also show a negative shift in the threshold voltage, a condition typically unattainable without oxidation layers or doping. Finally, we analyze the potential of AlGaN/Ga₂O₃-based HEMTs for future power electronic applications.