[TuP3G] Oxide Materials & Devices

[TuP3G-09] Growth and Characterization of β-(Al_xGa_1-x)₂O₃ Thin Films by MOCVD

〇Hyeong-Yun Kim¹, Sunjae Kim¹, Dowon Lee¹, JungHun Choi¹, Ji-Hyeon Park¹, Dae-Woo Jeon¹ (1. Korea Inst. of Ceramic Eng. and Tech. (Korea))

β-(Al_xGa_1-x)₂O₃ is an ultra-wide-bandgap semiconductor with strong potential for next-generation power electronic applications due to its high critical electric field, wide tunable bandgap, and favorable heterointerface properties with β-Ga₂O₃. In this study, β-(Al_xGa_1-x)₂O₃ films were grown by metal–organic chemical vapor deposition (MOCVD) using triethylgallium (TEGa) and trimethylaluminum (TMAl) as Ga and Al precursors, respectively. The compositional range and limits for Al incorporation were investigated by varying the TMAl-to-TEGa supply ratio on c-plane sapphire substrates. Then, the optimized growth conditions were applied to β-Ga₂O₃ substrates to examine the substrate dependent behavior of Al incorporation. A increase in the optical bandgap was observed with increasing TMAl ratio, and the Al composition was estimated to reach approximately 50% based on Vegard’s law. The β-(Al_xGa_1-x)₂O₃ films also demonstrated excellent insulating properties with leakage currents on the order of pA. These results provide insights into ternary composition engineering, highlighting its potential for future power semiconductor applications.