Growth of Single Crystals and Fabrication of GaN and AlN Wafers
Growth of Single Crystals and Fabrication of GaN and AlN Wafers
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单晶生长以及 GaN 和 AlN 晶圆的制造
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
R. Davis
中科院分区：
文献类型：
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作者：
Z. Sitar;R. Davis
摘要：通过控制蒸发金属Ga并与NH3反应，在(0001)蓝宝石衬底上生长了1050℃的GaN薄膜。研究了在此过程中Ga物种从源到衬底的迁移以及氨-液镓反应对Ga迁移的影响。将实验结果与理论预测进行了比较，以量化蒸汽生长技术中的输运机制。在NH3存在的情况下，Ga的输运远远超过了气相输运的预测上限。目视观察证实，有相当数量的镓以团簇而不是原子的形式离开源。纯的氮气直接流到熔融的砷源上方。这防止了熔融的Ga和NH3之间的直接接触和反应，并防止了Ga在源表面的溅射和GaN结壳的形成。它提高了Ga的蒸发速率，并能控制系统中的Ga输运和V/III比。结果表明，该过程是有限的传质过程，最大生长速率受控于Ga和反应性氨物种向衬底表面的传输。
Abstract : GaN thin films were grown on (0001) sapphire substrates at 1050 deg C by controlled evaporation of Ga metal and reaction with NH3. Transport of Ga species from source-to-substrate during this process and the influence of ammonia-liquid Ga reaction on Ga transport were investigated. Experimental results were compared to theoretical predictions to quantify the mechanism of transport in the vapor growth technique. In presence of NH3 Ga transport far exceeded the predicted upper limit for the vapor phase transport. Visual observations confirmed that a significant amount of Ga left the source in a cluster rather than atomic form. Pure N2 was flowed directly above the molten Ga source. This prevented direct contact and reaction between the molten Ga and NH3 and prevented Ga spattering and GaN crust formation on the source surface. It enhanced Ga evaporation rate and enabled control of Ga transport and V/III ratio in the system. The results showed that the process was mass transport limited and the maximum growth rate was controlled by transport of both Ga and reactive ammonia species to the substrate surface.