[J-4] Ultrawide Bandgap Semiconductor Devices

[J-4-02] Effect of Lattice Constraint on Structural Stability and Miscibility of (AlxGa1-x)2O3 Films: A First-Principles Study

〇Shuri Fujita¹, Toru Akiyama¹, Takahiro Kawamura¹, Tomonori Ito¹ (1. Mie Univ. (Japan))

Presentation style: On-site (in-person)

https://doi.org/10.7567/SSDM.2022.J-4-02

The structural stability and miscibility of (AlxGa1-x)2O3 alloys is theoretically investigated by means of elec-tronic structure calculations within density functional theory. Effects of lattice constraint due to sapphire sub-strate on the structural stability and miscibility are eval-uated from the energy difference between α-phase and β-phase (AlxGa1-x)2O3 and excess energies. For constrained systems due to sapphire substrate, only α-phase (AlxGa1-x)2O3 is found to be stabilized. Furthermore, the calcu-lated excess energies indicate that the lattice constraint drastically improve the miscibility of (AlxGa1-x)2O3. These results suggest that the lattice constrain is crucial for the stability and miscibility of (AlxGa1-x)2O3 alloys.