Impurity-induced Step Pinning and Recovery in MOVPE-grown (100) β-Ga2O3 Film: The Influence of Ga supersaturation

Abstract This study focuses on the impact of high-doping impurities (> 10¹⁸ cm⁻ ³) on the morphology of homoepitaxially grown (100) 4°off β-Ga₂O₃ film, as well as incorporating insights from the Cabrera-Vermilyea model (C-V model). Using atomic force microscopy (AFM) imaging, we reveal that under low supersaturation conditions, dopant-induced impurities lead to irregular step formation and growth stalling, inducing the step-bunching formation consistent with C-V model predictions. Conversely, higher supersaturation conditions restore desired step-flow morphology, resembling low-impurity growth states. It is also shown that the step-bunching formed under lower supersaturation conditions and high impurity concentration might induce unwanted structural defects and compensate the free carriers. These findings underscore the delicate interplay between dopant concentrations, growth morphology, and supersaturation in MOVPE-grown (100) β-Ga₂O₃ films, providing a comprehensive understanding for optimizing their electrical properties with respect to power electronics applications.