AlGaN films were grown on face-to-face annealed sputter-deposited AlN/sapphire (FFA Sp-AlN) templates via metalorganic vapor phase epitaxy (MOVPE), and the growth behavior of the AlGaN films was investigated. The sapphire substrates with small off-cut exhibited poor surface flatness of AlGaN grown on the FFA Sp-AlN templates owing to the formation of large hillock structures. To understand the origin of these hillock structures, the crystallinity and surface morphology of conventional fully MOVPE-grown AlN/sapphire (MOVPE-AlN) templates and the FFA Sp-AlN template were comprehensively studied. The screw- and mixed-type threading dislocation density of the FFA Sp-AlN template was estimated to be approximately 1.8 × 106 cm−2, which was two orders of magnitude lower than that of the MOVPE-AlN template. Consequently, the uniquely observed growth of the hillock structures in the FFA Sp-AlN templates was attributed to their low density of screw- and mixed-type threading dislocations. The large surface off-cut sapphire substrates suppressed the hillock structures on the FFA Sp-AlN templates. The improvement in surface flatness resulted in better optical properties of multiple quantum wells grown on the AlGaN layer. These results demonstrate a promising method for achieving highly efficient and cost effective AlGaN based deep ultraviolet light-emitting diodes.AlGaN films were grown on face-to-face annealed sputter-deposited AlN/sapphire (FFA Sp-AlN) templates via metalorganic vapor phase epitaxy (MOVPE), and the growth behavior of the AlGaN films was investigated. The sapphire substrates with small off-cut exhibited poor surface flatness of AlGaN grown on the FFA Sp-AlN templates owing to the formation of large hillock structures. To understand the origin of these hillock structures, the crystallinity and surface morphology of conventional fully MOVPE-grown AlN/sapphire (MOVPE-AlN) templates and the FFA Sp-AlN template were comprehensively studied. The screw- and mixed-type threading dislocation density of the FFA Sp-AlN template was estimated to be approximately 1.8 × 106 cm−2, which was two orders of magnitude lower than that of the MOVPE-AlN template. Consequently, the uniquely observed growth of the hillock structures in the FFA Sp-AlN templates was attributed to their low density of screw- and mixed-type threading dislocations. The large surface off-cut s...

中文翻译：

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在面对面退火溅射沉积 AlN 模板上抑制 MOVPE 生长的 AlGaN 中位错诱导的螺旋小丘

通过金属有机气相外延 (MOVPE) 在面对面退火的溅射沉积 AlN/蓝宝石 (FFA Sp-AlN) 模板上生长 AlGaN 薄膜，并研究了 AlGaN 薄膜的生长行为。由于形成大的小丘结构，具有小切屑的蓝宝石衬底在 FFA Sp-AlN 模板上生长的 AlGaN 的表面平整度较差。为了了解这些小丘结构的起源，全面研究了传统完全 MOVPE 生长的 AlN/蓝宝石 (MOVPE-AlN) 模板和 FFA Sp-AlN 模板的结晶度和表面形貌。FFA Sp-AlN 模板的螺纹和混合型螺纹位错密度估计约为 1.8 × 106 cm-2，比 MOVPE-AlN 模板低两个数量级。最后，在 FFA Sp-AlN 模板中观察到的小丘结构的独特生长归因于它们的低密度螺旋和混合型螺纹位错。大表面切割蓝宝石衬底抑制了 FFA Sp-AlN 模板上的小丘结构。表面平坦度的改善导致在 AlGaN 层上生长的多个量子阱的光学性能更好。这些结果证明了一种实现高效且具有成本效益的基于 AlGaN 的深紫外发光二极管的有前途的方法。 AlGaN 薄膜通过金属有机气相在面对面退火的溅射沉积 AlN/蓝宝石 (FFA Sp-AlN) 模板上生长外延 (MOVPE) 和 AlGaN 薄膜的生长行为进行了研究。由于形成大的小丘结构，具有小切屑的蓝宝石衬底在 FFA Sp-AlN 模板上生长的 AlGaN 的表面平整度较差。为了了解这些小丘结构的起源，全面研究了传统完全 MOVPE 生长的 AlN/蓝宝石 (MOVPE-AlN) 模板和 FFA Sp-AlN 模板的结晶度和表面形貌。FFA Sp-AlN 模板的螺纹和混合型螺纹位错密度估计约为 1.8 × 106 cm-2，比 MOVPE-AlN 模板低两个数量级。因此，在 FFA Sp-AlN 模板中观察到的小丘结构的独特生长归因于它们的低密度螺旋和混合型螺纹位错。大表面下料...