[TuP3G] Oxide Materials & Devices

[TuP3G-04] Molecular Beam Epitaxy of (-201) β-Ga₂O₃ and (002) κ-Ga₂O₃ on AlN

〇Andy Séguret^1,2, Julien Bosch¹, Marty Volant^2,3, Ilyass Jellal^1,2, Hervé Roussel², Fabien Jourdan¹, Yann Genuist¹, Eirini Sarigiannidou², Hanako Okuno³, Vincent Consonni², Eva Monroy¹ (1. Univ. Grenoble-Alpes, CEA, Grenoble INP, IRIG, PHELIQS, 38000 Grenoble (France), 2. Univ. Grenoble Alpes, CNRS, Grenoble INP, LMGP, 38000 Grenoble (France), 3. Univ. Grenoble-Alpes, CEA, Grenoble INP, IRIG, MEM, 38000 Grenoble (France))

We report a comprehensive study of the growth of Ga₂O₃ on (0001) AlN using plasma-assisted MBE, investigating the effect of substrate temperature and Ga flux on the morphology and crystallographic phase of the deposited material. At substrates temperatures > 700°C, and under O-rich conditions, the layers are pure monoclinic (-201)-oriented β-Ga₂O₃, with [010] β-Ga₂O₃ || <11-20> AlN epitaxial relationship. The growth rate collapses under Ga-rich conditions due to the favorable formation of volatile Ga₂O. At lower substrate temperatures, layers grown under O-rich conditions consist of a mixture of (-201) β-Ga₂O₃ and orthorhombic κ-Ga₂O₃, with the κ/β ratio increasing with higher metallic flux and lower substrate temperature. The growth rate increases systematically with the Ga flux, even under Ga-rich conditions, which lead to three-dimensional growth of mostly κ-Ga₂O₃ material. Finally, we demonstrate a significant increase of the growth rate by adding an indium flux during the growth, at temperatures that indium incorporation is inhibited.