Single-crystalline high-quality beta-Ga2O3 pseudo-substrate on sapphire through sputtering for epitaxial deposition

Guangying Wang; Shuwen Xie; William Brand; Saleh Ahmed Khan; Ahmed Ibreljic; Darryl Shima; Yueying Ma; Brahmani Challa; Fikadu Alema; Andrei Osinsky; Anhar Bhuiyan; Ganesh Balakrishnan; Shubhra S. Pasayat

arXiv · 2512.09294

Single-crystalline high-quality beta-Ga2O3 pseudo-substrate on sapphire through sputtering for epitaxial deposition

Guangying Wang·Shuwen Xie·William Brand·Saleh Ahmed Khan·Ahmed Ibreljic·Darryl Shima·Yueying Ma·Brahmani Challa·Fikadu Alema·Andrei Osinsky·Anhar Bhuiyan·Ganesh Balakrishnan·Shubhra S. Pasayat

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Abstract

Solid-phase epitaxy (SPE) of beta-Ga2O3 thin films by radio-frequency (RF) sputtering and then crystallized through high-temperature post-deposition annealing is employed on sapphire substrates, yielding a high-quality pseudo-substrate for subsequent buffer growth via MOCVD and LPCVD. Low roughness (<0.5 nm) and sharp single-crystalline diffraction peaks corresponding to the (-201), (-402), and (-603) reflections of beta-Ga2O3 were observed in the SPE beta-Ga2O3 film and the subsequent epitaxial buffer layer. N-doped Ga2O3 film on SPE Ga2O3 film grown by LPCVD showed step-assisted growth mode with reasonable electronic behavior with 45 cm^2/V-s mobility at a bulk carrier concentration of 1.3e17 cm^-3. These results suggest that SPE Ga2O3 is a promising pathway to advance the development of beta-Ga2O3 on foreign substrates.

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Guangying Wang, Shuwen Xie, William Brand, Saleh Ahmed Khan, Ahmed Ibreljic, Darryl Shima, Yueying Ma, Brahmani Challa, Fikadu Alema, Andrei Osinsky, Anhar Bhuiyan, Ganesh Balakrishnan, Shubhra S. Pasayat. 2025-12-10. Single-crystalline high-quality beta-Ga2O3 pseudo-substrate on sapphire through sputtering for epitaxial deposition. https://arxiv.org/abs/2512.09294

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