An effective KOH solution etching method in defect characterization of (100) β-Ga2O3

Abstract

Chemical etching offers a simple and efficient method for revealing defects in semiconductor materials, highlighting the importance of etchants selection. While H₃PO₄ is commonly used for defect-selective etching on the (100) surface of β-Ga₂O₃, its inability to effectively distinguish between different types of defects necessitates the use of alternative etchants, such as alkali solutions. In this work, we investigated the kinetics of defect-selective etching using 30 wt% KOH solution on the (100) surface of β-Ga₂O₃, determining an activation energy (E_a) of 0.671 eV and establishing an optimal defect-selective etching condition of 110 °C for 1.5 h. Three types of etch pits were observed by Optical Microscope (OM), and subsequently identified as dislocation-, strain- and void-related pits using transmission electron microscopy (TEM) combined with focused ion beam (FIB). Compared to H₃PO₄, KOH etching enables differentiation of these types defects on (100) surface of β-Ga₂O₃ directly by OM, offering a more effective and accurate approach for defect revelation. This research presents a novel and efficient method for defects revealing on the (100) plane, highlighting its potential in defects characterization in β-Ga₂O₃.