Chemical and electrical measurements of Ti/(010) β-Ga₂O₃ and Ti/(001) β-Ga₂O₃ interfaces were conducted as a function of annealing temperature using x-ray photoelectron spectroscopy (XPS), current density–voltage (J–V), and capacitance–voltage (C–V) measurements. XPS revealed partial Ti oxidation at both interfaces in the as-deposited condition, with more Ti oxidation on the (001) β-Ga₂O₃ epilayer surface than the (010) β-Ga₂O₃ substrate surface. The amount of oxidized Ti increased with annealing temperature. The Schottky barrier heights for as-deposited (unannealed) Au/Ti/(010) β-Ga₂O₃ and Au/Ti/(001) β-Ga₂O₃ contacts as determined from J–V and C–V measurements were between 0.64 and 0.83 eV. Shifts in XPS core level peaks for Ti/(010) β-Ga₂O₃ suggest that the Schottky barrier height decreases with temperature up to 350 °C for 10-min anneals and increases for 10-min anneals ≥460 °C. Taken together, the results suggest a strong dependence of Ti reactivity on the β-Ga₂O₃ surface, which can affect the electrical performance and stability of Ti/β-Ga₂O₃ ohmic contacts at elevated temperatures.

中文翻译：

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Ti/Au 与 β-Ga2O3 接触的电气和化学分析

Ti/(010) β -Ga ₂ O ₃和 Ti/(001) β -Ga ₂ O ₃界面的化学和电学测量是使用 X 射线光电子能谱 (XPS) 作为退火温度的函数进行的，电流密度–电压 (J-V) 和电容-电压 (C-V) 测量。XPS 揭示了在沉积状态下两个界面处的部分 Ti 氧化，(001) β -Ga ₂ O ₃外延层表面上的 Ti 氧化比 (010) β -Ga ₂ O _{3 多}基材表面。氧化钛的量随退火温度而增加。根据J-V 和 C-V 测量确定的沉积态（未退火）Au/Ti/(010) β -Ga ₂ O ₃和 Au/Ti/(001) β -Ga ₂ O ₃触点的肖特基势垒高度介于 0.64 和 0.83 eV 之间。Ti/(010) β -Ga ₂ O _{3 的}XPS 核心能级峰的偏移表明肖特基势垒高度随着温度升高至 350 °C 时 10 分钟退火而降低，并且随着 10 分钟退火 ≥460 °C 升高。总之，结果表明 Ti 反应性对β -Ga ₂ O有很强的依赖性₃表面，这会影响 Ti/ β -Ga ₂ O ₃欧姆接触在高温下的电性能和稳定性。