Proceedings of the
9th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN2022)
15 – 18 November 2022, Singapore

Towards Atomic-scale Smooth β-Ga2O3 Surfaces Manufacturing via Atmospheric Pressure Inductively Coupled Plasma

Yongjie Zhang1,2 and Hui Deng1,a

1Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China

2Department of Physics and Center for Advanced 2D Materials, National University of Singapore, 2 Science Drive 3, Singapore 117551, Singapore


β-Ga2O3 is an emerging next-generation ultra-wide bandgap semiconductor (UWBG) that shows great application potentials in novel high-power, high-frequency, and high-temperature semiconductor devices. However, β-Ga2O3 is indeed a typical difficult-to-machine material owing to its strong mechanical strength and chemical stability. Herein, we proposed an atomic-scale smoothing strategy, including two modes, namely plasma etching polishing (PEP) and plasma-induced atom migration manufacturing (PAMM), for β-Ga2O3 (010) substrate via atmospheric pressure inductively coupled plasma (ICP). We found that although the high-input-power CF4-O2-Ar plasma can achieve the polishing of β-Ga2O3, the co-existence of etching and migration effects would deteriorate the surface and prevent the further reduction of the surface roughness. We then adopted the low-input-power CF4-O2-Ar plasma and the high-input-power Ar plasma to treat the β-Ga2O3 substrate, and found that the scratched β-Ga2O3 can be polished to the atomic-scale smooth level with the Sa surface roughness of 0.424 nm and 0.347 nm mainly through the etching and migration processes, respectively. The PEP and PAMM methods proposed here are highly efficient, compared with the widely used chemical mechanical polishing (CMP). We believe that both PEP and PAMM would greatly promote the further development of β-Ga2O3-based power electronics.

Keywords: β-Ga2O3, Next-generation semiconductor, Atomic-scale smooth surface, Plasma, ACSM

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