【作者】 杜阳；

【导师】 李培咸；

【作者基本信息】 西安电子科技大学 ， 材料物理与化学， 2009， 硕士

【摘要】 本论文通过MOCVD生长手段,通过一系列实际的生长和测试实验,在蓝宝石衬底上异质外延了高Al组分的AlxGa1-xN外延层,并且针对多种缓冲层技术下的成核层生长、脉冲缓冲层生长和超晶格缓冲层生长工艺,通过材料生长和材料表征两方面,研究了关键层结构中的关键工艺参数对AlxGa1-xN外延材料质量的影响,对关键的工艺参数进行了一系列的优化试验,制备出了高质量的AlN外延材料和高Al组份AlGaN外延材料。对不同Al组分含量的高Al组分AlxGa1-xN外延材料样品,采用XRD对其进行了结晶质量和Al组份的表征分析,测定了实际样品具体的Al组分含量,研究了不同Al组分含量的AlxGa1-xN外延层在实际的螺位错密度、刃位错密度和晶格常数方面的差异。更多还原

【Abstract】 The research of this paper is mainly based on MOCVD crystal growth technical, good-crystal-quality and crack free AlxGa1-xN epilayer with high-Al concentration have been grown on sapphire substrate through a series of growing and testing experiments. And the key point of the buffer layers, the influence factor of several process parameters to the crystal quality have been investigated from the both sides of crystal growth and characterization analysis.Then the process parameters are optimized step by step and the role of each parameter are forecasted during the growing process. Finally, through comparison of the experiment results, the optimized process parameters has been obtained and with which high-Al composition AlxGa1-xN material with best quality could be grown sucessfully.Based on the optimized process formula, AlxGa1-xN epilayers with different Al concentration have been grown by adjusting the incorporation of Al. And the real value of Al concentration are determined by XRD.Furthermore, the differences between density of both screw dislocation and edge dislocation have been investigated, and the paractical crystal constant are also be calculated.更多还原