Optimization of interface characteristics between dielectric and non-polar GaN surface is very important and urgent for vertical GaN MOS device whose channel is perpendicular to the conventional cplane. In this work, the effects of piranha cleaning and N2 post deposition annealing (PDA) to the interface between atomic-layer-deposited (ALD)-Al2O3 and a-plane GaN samples were comprehensively investigated by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and photo-assisted capacitance-voltage (C-V) measurements. The piranha cleaning and N2 annealing can improve interface characteristics through the reduction in surface roughness and Ga-O bonds, respectively. Therefore, the frequency dispersion and hysteresis are nearly suppressed with a low interface trap quantity (Qit) of 4.1 x 1011 cm-2 and a low average interface state density (Dit) of 2.04 x 1011 cm-2·eV-1 from photoassisted C-V measurements, showing the great promise of utilizing piranha pretreatment, buffered oxide etch (BOE) dip, and N2 annealing as an effective route to improve the vertical GaN MOS interface properties.

中文翻译：

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表面处理和沉积后退火对a-面GaN ALD-Al钪侽钪界面性能的影响


对于沟道垂直于传统c面的垂直GaN MOS器件来说，电介质和非极性GaN表面之间的界面特性的优化是非常重要和紧迫的。在这项工作中，通过X射线光电子能谱（XPS）全面研究了食人鱼清洗和N2沉积后退火（PDA）对原子层沉积（ALD）-Al2O3和a面GaN样品之间界面的影响，原子力显微镜 (AFM) 和光辅助电容电压 (CV) 测量。食人鱼清洗和氮气退火可以分别通过降低表面粗糙度和Ga-O键来改善界面特性。因此，光辅助CV具有4.1 x 1011 cm-2的低界面陷阱量（Qit）和2.04 x 1011 cm-2·eV-1的低平均界面态密度（Dit），几乎抑制了频率色散和滞后现象测量结果显示，利用食人鱼预处理、缓冲氧化物蚀刻 (BOE) 浸入和 N2 退火作为改善垂直 GaN MOS 界面特性的有效途径具有巨大前景。