Gallium oxide (Ga2O3) has attracted much attention because of its notable advantages, including its low cost and a high critical breakdown field. In this study, atomic layer deposition was used to deposit high-quality Ga2O3 onto a SiC substrate with high thermal conductivity. The band arrangement of the Ga2O3/SiC heterojunction was investigated by modulating oxygen vacancies using different post-annealing atmospheres. The results demonstrated that recrystallization of Ga2O3 resulted in a good crystalline state because of the rearrangement of Ga and O atoms following high-temperature annealing. Simultaneously, the roughness of all annealed samples increased. X-ray photoelectron spectroscopy analysis revealed a significant reduction of oxygen vacancy content in samples that were annealed in an oxygen atmosphere; this is attributed to the replacement of oxygen vacancies by oxygen atoms. Conversely, oxygen vacancies increased in an oxygen-free environment. The band offsets (valence band, conduction band) were respectively determined to be (−1.03 eV, 0.5 eV), (−0.63 eV, 0.9 eV), (−1.39 eV, 0.16 eV), and (−1.32 eV, 0.22 eV) for the as-deposited sample and annealed samples with O2, N2, and Ar atmospheres. Finally, the impact that various ratios of oxygen vacancies have on the energy band structure of Ga2O3 was studied using first-principles calculations. Calculations on heterojunctions confirmed that the introduction of oxygen vacancies reduced the potential barrier at the interface and promoted the movement of electrons. Thus, this study provides valuable insights for the design and application of Ga2O3/SiC heterojunction devices.

中文翻译：

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退火气氛对等离子体增强原子层沉积生长的 Ga2O3/SiC 异质结能带对准的影响


氧化镓 （Ga2O3） 因其成本低、临界击穿场高等显著优势而备受关注。在本研究中，原子层沉积用于将高质量的 Ga2O3 沉积到具有高导热率的 SiC 衬底上。通过使用不同的后退火气氛调节氧空位来研究 Ga2O3/SiC 异质结的能带排列。结果表明，由于高温退火后 Ga 和 O 原子的重排，Ga2O3 的再结晶产生了良好的结晶状态。同时，所有退火样品的粗糙度都增加了。X 射线光电子能谱分析显示，在氧气气氛中退火的样品中的氧空位含量显著降低;这归因于氧原子取代氧空位。相反，在无氧环境中，氧气空位增加。沉积态样品和具有 O2、N2 和 Ar 气氛的退火样品的能带偏移（价带、导带）分别为 （−1.03 eV， 0.5 eV）、（−0.63 eV， 0.9 eV）、（−1.39 eV， 0.16 eV） 和 （−1.32 eV， 0.22 eV）。最后，使用第一性原理计算研究了各种比例的氧空位对 Ga2O3 能带结构的影响。异质结的计算证实，氧空位的引入降低了界面处的势垒并促进了电子的运动。因此，本研究为 Ga2O3/SiC 异质结器件的设计和应用提供了有价值的见解。