Wet etching in β-Ga2O3 bulk single crystals

Beta-phase gallium oxide (beta-Ga2O3) bulk single crystals have received increasing attention due to their fantastic performances and widespread use in power devices and solar-blind photodetectors. Wet etching has proved to be a simple and effective approach for visualization of defects, polishing of wafers, and patterning of substrates. Recently, a large number of different strategies have been developed for wet etching of beta-Ga2O3 substrates. Here we review recent advances in wet etching of beta-Ga2O3 substrates with an aim to comprehensively understand the etching behavior and mechanism. We classify wet etching into conventional etching including chemical etching, defect-selective etching, patterning, and chemical mechanical polishing and unconventional etching (i.e., electrochemical and electroless etchings including photo- and/or metal-assisted ones) depending on the input of extra assistance or not. In each category, the key parameters that control the etching kinetics were discussed and a number of examples were highlighted. This review intends to shed light on how to design appropriate etching strategies for various purposes and applications.

Automated summary

This review article summarizes recent advances in wet etching of β-Ga2O3 substrates, aiming to comprehensively understand the etching behavior and mechanism. Wet etching is classified into conventional and unconventional types, each with key parameters controlling etching kinetics discussed and examples highlighted. The review intends to provide guidance on designing appropriate etching strategies for various purposes and applications.