Interface characteristics of frequency dispersion, flatband voltage (V_fb) shift, fixed charge (Q_IL), and interface state density (D_it) in β-Ga₂O₃/Al₂O₃/Pt capacitors were investigated after postmetallization annealing (PMA) at 300 °C in N₂ using a conductance method and a photo-assisted capacitance-voltage technique. After PMA, no frequency dispersion was observed, and the Q_IL and D_it values related to interface states near the conduction band edge (E_c) were significantly reduced to the ranges of −4 to +1 × 10¹¹ cm⁻² and 3 to 8 × 10¹¹ cm⁻² eV⁻¹ at E_c− E = 0.4 eV, respectively, in the capacitors subjected to a low postdeposition annealing (PDA) temperature region of 300–600 °C. In contrast, a large frequency dispersion, and high Q_IL (−2 × 10¹² cm⁻²), and D_it (4–5 × 10¹² cm⁻² eV⁻¹ at E_c− E = 0.4 eV) of the capacitors with a high PDA temperature region of 700–900 °C remained. This difference is considered to be due to hard structural changes at the multilayer level by the interdiffusion of Ga and Al at the β-Ga₂O₃/Al₂O₃ interface caused by PDA above 700 °C. In contrast, the average D_it values due to the electrons deeply trapped below the midgap between 2.6 and 3.3 eV decreased from 2 × 10¹² to 1 × 10¹¹ cm⁻² eV⁻¹ as the PDA temperature was increased from 300 to 900 °C, respectively, before PMA. No significant change in D_it below the midgap was observed, regardless of the PDA temperature after PMA. Note that the PMA treatment effectively improved only the interface properties near the E_c after treatment in the low PDA temperature region below 600 °C.

中文翻译：

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金属化后退火后的β-Ga2O3/ Al2O3 / Pt电容器的界面特性

接口频率分散的特性，平带电压（V _FB）移位，固定电荷（Q _IL），和界面态密度（d_它在β-Ga）的₂ ö ₃ / Al的₂ ö ₃ /铂电容器在postmetallization退火后调查（在300°C的N _2中使用电导方法和光辅助电容电压技术。在PMA之后，未观察到频率色散，并且与导带边缘（E _c）附近的界面状态有关的Q _IL和D _it值显着减小至-4至+1×10 ¹¹  cm ^-2的范围。在经过300-600°C的低后沉积退火（PDA）温度区域的电容器中，分别在E _c -E = 0.4 eV时为3至8×10 ¹¹  cm ^-2  eV ^-1。相反，大的频率分散，和高Q _IL（-2×10 ¹²厘米^-2），和d_它（4-5×10 ¹² 厘米^-2  eV的^-1 E处_Ç -的E = 0.4 eV）的剩下的PDA温度范围为700–900°C的电容器。这种差别被认为是由于在的β-Ga在多层级硬结构变化由Ga和Al的相互扩散₂ ö700°C以上的PDA导致₃ / Al ₂ O ₃接口。相反，随着PDA温度从300°C升高到900° C _，由于深陷在2.6和3.3 eV之间的中间能隙以下的电子而导致的平均D _it值从2×10 ¹²降低到1×10 ¹¹  cm ^-2  eV ^-1。 C分别在PMA之前。不管PMA后的PDA温度如何，在中间间隙以下的D _it均未观察到显着变化。注意，在低于600°C的PDA低温度区域中，PMA处理仅有效地改善了处理后E _c附近的界面特性。