Influence of HCl concentration in source solution and growth temperature on formation of α-Ga2O3 film via mist-CVD process

We have examined the effect of synthesis conditions on α-Ga2O3 film, one of the ultra-wide bandgap semiconductors, on c-plane sapphire substrate via mist CVD process. The resultant film is dominantly composed of α-Ga2O3 phase, but a small amount of κ-Ga2O3 phase coexists when the growth temperature...

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Bibliographic Details
Published in:Japanese Journal of Applied Physics 2023-06, Vol.62 (SF), p.SF1024
Main Authors: Wakamatsu, Takeru, Takane, Hitoshi, Kaneko, Kentaro, Araki, Tsutomu, Tanaka, Katsuhisa
Format: Article
Language:English
Subjects:
Chemical vapor deposition
Ga
gallium oxide
Gallium oxides
growth conditions
mist-CVD
Sapphire
Substrates
Surface roughness
Wide bandgap semiconductors
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Summary:We have examined the effect of synthesis conditions on α-Ga2O3 film, one of the ultra-wide bandgap semiconductors, on c-plane sapphire substrate via mist CVD process. The resultant film is dominantly composed of α-Ga2O3 phase, but a small amount of κ-Ga2O3 phase coexists when the growth temperature is higher. The source solution containing higher concentration of HCl expands the range of temperatures at which single-phase α-Ga2O3 is grown and suppresses the inclusion of κ-Ga2O3 at higher growth temperatures. Moreover, the growth with higher concentration of HCl up to 0.66 mol l−1 increases the growth rate and improves the surface roughness. Thus, HCl has a crucial role in the selective growth of α-Ga2O3 and the quality of the film. Also, some pits are observed at the surface of α-Ga2O3 and κ-Ga2O3 is precipitated inside the pit defect when the concentration of HCl is low and the growth temperature is high.
ISSN:0021-4922
1347-4065
DOI:10.35848/1347-4065/acc9cf