HVPE Growth of Si-Doped β-Ga2O3 on Sapphire: Influence of Substrate Offcut on Structural and Electrical Properties
Abstract
Si-doped β-Ga2O3 films were heteroepitaxially grown on sapphire substrates using HVPE. The influence of sapphire offcut on growth kinetics, surface morphology, crystalline quality, and electrical transport properties was systematically investigated. Growth kinetics studies revealed a strong dependence of deposition rate on HCl flow, growth pressure, and source-to-substrate distance, with growth rates reaching up to 30 μm/hr. Increasing sapphire offcut angle from 0∘ to 8∘ promoted a transition from multidirectional growth to highly aligned terrace-dominated surfaces, reducing the surface roughness from 14.69 to 2.74 nm. The improved surface morphology was accompanied by enhanced crystalline quality, with phase-pure (-201)-oriented β-Ga2O3 growth and a reduction in the rocking-curve full width at half maximum from 994 to 414 arcsec as the sapphire offcut increased. Electrical characterization of films grown on 6∘ offcut substrates yielded carrier concentrations ranging from 1.0×1017 to 3.4×1018 cm−3. A maximum room-temperature electron mobility of 100cm2/V·s was achieved at a carrier concentration of 1.0×1017cm−3, representing the highest reported room-temperature mobility for HVPE-grown β-Ga2O3 on a foreign substrate. Analysis of the temperature-dependent transport characteristics yielded donor activation energies of 35 and 90 meV together with a low acceptor concentration of 3×1015 cm−3, consistent with the improved crystalline quality achieved on the offcut sapphire substrates. These results demonstrate that HVPE is capable of producing high-quality β-Ga2O3 heteroepitaxial layers with good crystalline quality and carrier transport characteristics, providing a promising pathway for scalable β-Ga2O3 epitaxy on low-cost foreign substrates.
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BibTeX
@misc{sarker2026hvpe,
title = {{HVPE Growth of Si-Doped $β$-Ga$_2$O$_3$ on Sapphire: Influence of Substrate Offcut on Structural and Electrical Properties}},
author = {Sourav Sarker and Saleh Ahmed Khan and Ahmed Ibreljic and Anhar Bhuiyan},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2606.05607},
eprint = {2606.05607},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.05607},
}
RIS
TY - UNPB
TI - HVPE Growth of Si-Doped β-Ga_2O_3 on Sapphire: Influence of Substrate Offcut on Structural and Electrical Properties
AU - Sourav Sarker
AU - Saleh Ahmed Khan
AU - Ahmed Ibreljic
AU - Anhar Bhuiyan
PY - 2026
DA - 2026/09/29
PB - arXiv
DO - 10.48550/arxiv.2606.05607
UR - https://arxiv.org/abs/2606.05607
AB - Si-doped β-Ga_2O_3 films were heteroepitaxially grown on sapphire substrates using HVPE. The influence of sapphire offcut on growth kinetics, surface morphology, crystalline quality, and electrical transport properties was systematically investigated. Growth kinetics studies revealed a strong dependence of deposition rate on HCl flow, growth pressure, and source-to-substrate distance, with growth rates reaching up to 30 μm/hr. Increasing sapphire offcut angle from 0^∘ to 8^∘ promoted a transition from multidirectional growth to highly aligned terrace-dominated surfaces, reducing the surface roughness from 14.69 to 2.74 nm. The improved surface morphology was accompanied by enhanced crystalline quality, with phase-pure (-201)-oriented β-Ga_2O_3 growth and a reduction in the rocking-curve full width at half maximum from 994 to 414 arcsec as the sapphire offcut increased. Electrical characterization of films grown on 6^∘ offcut substrates yielded carrier concentrations ranging from 1.0×10^17 to 3.4×10^18 cm^−3. A maximum room-temperature electron mobility of 100cm^2/V·s was achieved at a carrier concentration of 1.0×10^17cm^−3, representing the highest reported room-temperature mobility for HVPE-grown β-Ga_2O_3 on a foreign substrate. Analysis of the temperature-dependent transport characteristics yielded donor activation energies of 35 and 90 meV together with a low acceptor concentration of 3×10^15 cm^−3, consistent with the improved crystalline quality achieved on the offcut sapphire substrates. These results demonstrate that HVPE is capable of producing high-quality β-Ga_2O_3 heteroepitaxial layers with good crystalline quality and carrier transport characteristics, providing a promising pathway for scalable β-Ga_2O_3 epitaxy on low-cost foreign substrates.
ER -