Metalorganic chemical vapor deposition epitaxy of β-Ga2O3 films on (001) Ga2O3 substrates with fast growth rates

Background carbon incorporation and film cracking issue in (001) β-Ga2O3 films grown by metalorganic chemical vapor deposition (MOCVD) are investigated. Quantitative secondary ion mass spectrometry analysis shows that increasing the O2 flow rate significantly reduces carbon concentration, suggesting the importance of optimizing the VI/III ratio and growth temperature to achieve low compensation and controllable doping in MOCVD of (001) Ga2O3 films. MOCVD growth of (001) β-Ga2O3 films with a film thickness of 25 μm at a growth rate of 10 μm/h is achieved. However, film cracking remains a persistent challenge. Reducing the growth rate by adjusting the trimethylgallium (TMGa) flow rate or increasing chamber pressure effectively suppresses cracking, but it results in slower growth rates. In addition, lower growth temperature and high chamber pressure can help suppressing surface reconstruction and reduce the formation of cracking. Buffer layers grown at 850 °C, 100 Torr, and 58 μmol/min of TMGa significantly improve surface morphology of drift layers. Moreover, the use of AlGaO buffer layers with 8% of Al and a thickness of ∼130 nm leads to a lower crack density. X-ray rocking curve analysis confirms high crystalline quality at a growth rate of 10 μm/h, with no degradation observed from the introduction of an AlGaO buffer layer. These optimized growth conditions effectively improve surface smoothness and minimize defects. Results from this work provide fundamental insights in MOCVD epitaxy of β-Ga2O3 on (001) Ga2O3 substrates, revealing the opportunities and challenges of MOCVD (001) β-Ga2O3 thin films with fast growth rates for high-power electronic device technology.