Abstract The crystal quality and morphological properties of semi-polar (11–22) gallium GaN were enhanced by introducing the In-Situ Multiple Ammonia Treatment (I-SMAT) method. On- and off-axis x-ray rocking curve (XRC) analysis reveals that I-SMAT would reduce several types of crystal defect namely prismatic stacking faults, basal stacking fault type I and II, and partial/perfect dislocations. By implementing an optimized flow of ammonia (NH3) and number of treated GaN pairs, the arrowhead-like features of semi-polar (11–22) GaN was effectively reduced the root mean square roughness from 4.52 to 3.07 nm. High atomic force microscopy (AFM) magnification scan demonstrated the alteration of the grain structure on the surface to become more compact and orderly arranged resulting in narrowing/shallowing of the interfacial valleys between grains. Great influence of employed I-SMAT pairs and NH3 flux was observed from XRC and AFM analysis. Conversely, excessive NH3 flux during this approach would roughen the structural and morphological properties of the semi-polar epilayer whereby the alternating thin GaN epilayer would undergo the selective-area etching to the extreme.

中文翻译：

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通过原位多氨处理在 m 面蓝宝石上调节半极性 (11-22) GaN 的晶体质量和表面结构

摘要 通过引入原位多氨处理 (I-SMAT) 方法提高了半极性 (11-22) 镓 GaN 的晶体质量和形态特性。轴上和轴外 X 射线摇摆曲线 (XRC) 分析表明，I-SMAT 将减少几种类型的晶体缺陷，即棱柱形堆垛层错、基底层错 I 型和 II 型以及部分/完全位错。通过实施优化的氨 (NH3) 流和处理过的 GaN 对的数量，半极性 (11-22) GaN 的箭头状特征有效地将均方根粗糙度从 4.52 降低到 3.07 nm。高原子力显微镜 (AFM) 放大扫描表明，表面晶粒结构的改变变得更加紧凑和有序，导致晶粒之间的界面谷变窄/变浅。从 XRC 和 AFM 分析观察到所采用的 I-SMAT 对和 NH3 通量的巨大影响。相反，在这种方法中过多的 NH3 流量会使半极性外延层的结构和形态特性变得粗糙，从而交替的薄 GaN 外延层将经历极端的选择性区域蚀刻。