Effect of NH3 flow on incorporation efficiency of Al composition and reduction of surface donor states in AlGaN grown by MOVPE

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• 作者：Tao Gao ; Ruimin Xu ; Dongguo Zhang ; Zhonghui Li ; Daqing Peng ; Xun Don and Tangsheng Chen
• 刊名：physica status solidi (c)
• 出版年：2016
• 出版时间：May 2016
• 年：2016
• 卷：13
• 期：5-6
• 页码：214-216
• 全文大小：461K
• ISSN：1610-1642a

文摘

We have studied the effect of various ammonia (NH₃) flow rates on AlGaN film grown on GaN using c-plane sapphire as substrate by metal organic chemical vapour deposition. The influences of NH₃ flow on the species diffusion anisotropy of thick AlGaN films were investigated by scanning electron microscopy, atomic force microscopy and high-resolution X-ray diffraction measurements. It is demonstrated that, in addition to the larger NH₃ flow, growth of the AlGaN epilayer under the same trimethylaluminum (TMAl) flow condition as others is a critical factor for less micro-cracks. The results of X-ray double crystal diffraction showed that the AlGaN films with larger ammonia flow exhibited lower Al content and smaller (0002) rocking curve width, and while NH₃ flow rate reached 23 liter per minute, a (0002) rocking curve width of 295 arcsecond was reached. (