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In this study, we comprehensively investigated the growth of β-Ga2O3on (001) on-axis Ga2O3substrates via metalorganic chemical vapor deposition (MOCVD) using both triethylgallium (TEGa) and trimethylgallium (TMGa) as the Ga precursors. For MOCVD growth with TEGa, the group VI/III molar ratio was tuned with different TEGa molar flow rates. The correlation between growth conditions and the surface morphology, growth rate, and electron transport properties of MOCVD-grown (001) β-Ga2O3thin films is comprehensively analyzed. Room temperature mobility of 85 cm2/V s with carrier concentration of 2.0 × 1017cm–3was measured for a film grown using the TEGa molar flow rate of 19 μmol/min and VI/III molar ratio of 934. For MOCVD growth of (001) Ga2O3using TMGa, we observed the occurrence of cracking along the [010] direction in the grown films, which was found to be closely related to the film thickness and growth rate. The relatively smooth surface morphology of the films with cracks is attributed to the strain relaxation. (001) β-Ga2O3films containing rotation domains with (−401) plane were observed from high-resolution X-ray diffraction (XRD) and confirmed with atomic-resolution scanning transmission electron microscopy (STEM) imaging. Under the same growth condition, (001) β-Ga2O3films contain higher carbon concentration as compared to that of the (010) β-Ga2O3films. Results from this work provide fundamental insights into the MOCVD epitaxy of β-Ga2O3on (001) Ga2O3substrates, revealing the opportunities and challenges of MOCVD growth of (001) β-Ga2O3thin films with fast growth rates for high-power electronic device technology.

In this work, metalorganic chemical vapor deposition (MOCVD) of (010) β-Ga2O3with fast growth rates was investigated using trimethylgallium (TMGa) as the gallium (Ga) precursor. Key growth parameters including precursor/carrier gas flow, growth temperature, chamber pressure, and group VI/III molar flow ratio were systematically mapped. Surface morphology and charge transport properties of the homo-epi (010) β-Ga2O3thin films were probed to correlate with the crystalline quality. The growth rate of (010) β-Ga2O3thin film increases as the TMGa flow rate increases, and high-quality epi-film is achievable with a fast growth rate up to ∼3 μm/h. By tuning the n-type dopant silane flow rate, the net charge carrier concentration was tuned from ∼1016to 1019cm–3. Room-temperature mobility as high as 190 cm2/V·s was measured for a sample grown with a growth rate of 2.95 μm/h and an electron concentration of 1.8 × 1016cm–3. Temperature-dependent Hall measurement revealed a peak mobility value of ∼3400 cm2/V·s at 53 K. The extracted low compensation level of NA∼ 1.5 × 1015cm–3indicates the high purity of the MOCVD growth of the (010) β-Ga2O3film using TMGa as the Ga precursor. Quantitative secondary-ion mass spectroscopy characterization revealed a relatively high C concentration of 7 × 1016cm–3, indicating that C does not serve as a compensator or a donor in MOCVD grown β-Ga2O3. The results from this study demonstrate the feasibility to grow high-quality Ga2O3thin films with fast growth rates, critical for developing high power electronic device technology.