Defect Suppression in AlN Epilayer Using Hierarchical Growth Units

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• 作者：Qinqin Zhuang ; Wei Lin ; Weihuang Yang ; Wencao Yang ; ChengCheng Huang ; Jinchai Li ; HangYang Chen ; Shuping Li ; Junyong Kang
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：July 11, 2013
• 年：2013
• 卷：117
• 期：27
• 页码：14158-14164
• 全文大小：424K
• 年卷期：v.117,no.27(July 11, 2013)
• ISSN：1932-7455

文摘

Growing AlN layers remains a significant challenge because it is subject to a large volume fraction of grain boundaries. In this study, the nature and formation of the AlN growth mechanism is examined by ab initio simulations and experimental demonstration. The calculated formation enthalpies of the constituent elements, including the Al/N atom, Al鈥揘 molecule, and Al鈥揘₃ cluster, vary with growth conditions in N-rich and Al-rich environments. Using the calculation results as bases, we develop a three-step metalorganic vapor-phase epitaxy, which involves the periodic growth sequence of (i) trimethylaluminum (TMAl), (ii) ammonia (NH₃), and (iii) TMAl+NH₃ supply, bringing in hierarchical growth units to improve AlN layer compactness. A series of AlN samples were grown, and their morphological and luminescent evolutions were evaluated by atomic force microscopy and cathodoluminescence, respectively. The proposed technique is advantageous because the boundaries and defect-related luminescence derived are highly depressed, serving as a productive platform from which to further optimize the properties of AlGaN semiconductors.