In this work, we report on the anisotropic etching characteristics of \b{eta}-Ga2O3 using triethylgallium (TEGa) performed in-situ within an MOCVD chamber. At sufficiently high substrate temperature, TEGa can act as a strong etchant for \b{eta}-Ga2O3 utilizing the suboxide reaction between Ga and Ga2O3. We observe that due to monoclinic crystal structure of \b{eta}-Ga2O3, TEGa etching on both (010) and (001) substrates is highly anisotropic in nature, both in terms of sidewall roughness and lateral etch rate. Smooth sidewalls are only obtained along crystal orientations that minimize sidewall surface energy. Utilizing this technique we also demonstrate deep sub-micron fins with smooth sidewalls and high aspect ratios. Furthermore, we also demonstrate the damage free nature of TEGa etching by fabricating Schottky diodes on the etched surface which display no change in net donor concentration.
@article{arxiv.2408.05824,
title = {In-situ Patterned Damage-Free Etching of 3-Dimensional Structures in \b{eta}-Ga2O3 using Triethylgallium},
author = {Nabasindhu Das and Fikadu Alema and William Brand and Abishek Katta and Advait Gilankar and Andrei Osinsky and Nidhin Kurian Kalarickal},
journal= {arXiv preprint arXiv:2408.05824},
year = {2024}
}