III-Nitride/Ga2O3 heterostructure for future power electronics: opportunity and challenges

Ga₂O₃ has become the new focal point of high-power semiconductor device research due to its superior capability to handle high voltages in smaller dimensions and with higher efficiencies compared to other commercialized semiconductors. However, the low thermal conductivity of the material is expected to limit device performance. To compensate for the low thermal conductivity of Ga₂O₃ and to achieve a very high density 2-dimensional electron gas (2DEG), an innovative idea is to combine Ga₂O₃ with III-Nitrides (which have higher thermal conductivity), such as AlN. However, metal-polar AlN/β-Ga₂O₃ heterojunction provide type-II heterojunction which are beneficial for optoelectronic application. because of the negative value of specific charge density. On the other hand, N-polar AlN/β-Ga₂O₃ heterostructures provide higher 2DEG concentration and larger breakdown voltage compared to conventional AlGaN/GaN devices. This advancement would allow the demonstration of RF power transistors with a 10x increase in power density compared to today's State of the Art (SoA) and provide a solution to size, weight, and power-constrained applications.