High-Mobility MOCVD β-Ga2O3 Epitaxy with Fast Growth Rate Using Trimethylgallium

In this work, metalorganic chemical vapor deposition (MOCVD) of (010) beta-Ga2O3 with 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) beta-Ga2O3 thin films were probed to correlate with the crystalline quality. The growth rate of (010) beta-Ga2O3 thin film increases as the TMGa flow rate increases, and high-quality epi-film is achievable with a fast growth rate up to similar to 3 mm/h. By tuning the n-type dopant silane flow rate, the net charge carrier concentration was tuned from similar to 10(16) to 10(19) cm(-3). Room-temperature mobility as high as 190 cm(2)/V.s was measured for a sample grown with a growth rate of 2.95 mm/h and an electron concentration of 1.8 x 10(16) cm(-3). Temperature-dependent Hall measurement revealed a peak mobility value of similar to 3400 cm(2)/V.s at 53 K. The extracted low compensation level of NA similar to 1.5 x 10(15) cm(-3) indicates the high purity of the MOCVD growth of the (010) beta-Ga2O3 film using TMGa as the Ga precursor. Quantitative secondary-ion mass spectroscopy characterization revealed a relatively high C concentration of 7 x 10(16) cm(-3), indicating that C does not serve as a compensator or a donor in MOCVD grown beta-Ga2O3. The results from this study demonstrate the feasibility to grow high-quality Ga2O3 thin films with fast growth rates, critical for developing high power electronic device technology.

Automated summary

In this study, high-quality Ga2O3 thin films were successfully grown with fast growth rates using metalorganic chemical vapor deposition (MOCVD). Key growth parameters and the flow rate of n-type dopant silane were adjusted to achieve high crystalline quality, high mobility, and low compensation level. These results are crucial for the development of high power electronic device technology.