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In this Letter, the role of background carbon in metalorganic chemical vapor deposition (MOCVD) β-Ga2O3 growth using trimethylgallium (TMGa) as the Ga precursor was investigated. The quantitative C and H incorporations in MOCVD β-Ga2O3 thin films grown at different growth rates and temperatures were measured via quantitative secondary ion mass spectroscopy (SIMS). The SIMS results revealed both [C] and [H] increase as the TMGa molar flow rate/growth rate increases or growth temperature decreases. The intentional Si incorporation in MOCVD β-Ga2O3 thin films decreases as the growth rate increases or the growth temperature decreases. For films grown at relatively fast growth rates (GRs) (TMGa > 58 μmol/min, GR > 2.8 μm/h) or relatively low temperature (<950 °C), the [C] increases faster than that of the [H]. The experimental results from this study demonstrate the previously predicted theory—H can effectively passivate the compensation effect of C in n-type β-Ga2O3. The extracted net doping concentration from quantitative SIMS {[Si]-([C]-[H])} agrees well with the free carrier concentration measured from Hall measurement. The revealing of the role of C compensation in MOCVD β-Ga2O3 and the effect of H incorporation will provide guidance on designing material synthesis for targeted device applications.
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This content will become publicly available on July 1, 2026
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.
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- Award ID(s):
- 2231026
- PAR ID:
- 10628416
- Publisher / Repository:
- AIP
- Date Published:
- Journal Name:
- Journal of Vacuum Science & Technology A
- Volume:
- 43
- Issue:
- 4
- ISSN:
- 0734-2101
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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