Assessment of the β-Ga2O3 substrate orientation for µm-level-thick layers via MOVPE process

Abstract This study explores the transfer of optimized growth conditions from (100) to (010) orientation in β-Ga₂O₃ films via the metalorganic vapor phase epitaxy (MOVPE) process, aiming to uncover a shared growth window. While (100) orientation demands intentional substrate treatment for ideal growth, (010) orientation requires specific growth conditions to lower surface roughness. Our findings reveal that a low O₂/Ga flux ratio growth condition enables a uniform process for both orientations across various film thicknesses with smooth surface roughness. Notably, extended defects (nanopipes) manifest prominently in EFG-grown substrates impact film quality (hillock formation) and electrical properties in films of > 3 µm thick. Nanopipes-free Czochralski-grown crystals enable thick films (4 µm) without deteriorating their structural quality and electrical properties.