【作者】 吕海涛；

【导师】 张维连； 任丙彦；

【作者基本信息】 河北工业大学 ， 材料物理与化学， 2004， 硕士

【摘要】 本文用化学腐蚀法对CZ法生长的φ50mm蓝宝石单晶中的位错和缺陷进行了分析研究，并采用金相显微镜和SEM对其进行了显微观察和分析。进行了不同温度、不同的试剂以及不同的腐蚀时间条件下的缺陷显示实验。发现，用熔融的KOH腐蚀剂在290℃下腐蚀15分钟时，显示的位错最为清晰、准确，效果最佳。 利用原子力显微镜（AFM）观察了蓝宝石衬底和GaN外延层中缺陷形貌以及衬底与外延之间生长界面的情况，发现在蓝宝石衬底上外延GaN，当蓝宝石中的位错密度小于10⁵／cm²时，GaN中的位错密度增值到10⁸～10⁹／cm²。且GaN外延层中的位错密度与蓝宝石衬底中的位错密度没有线性关系。用扫描电镜（SEM）、XPS、电子探针和紫外荧光光谱仪测量了蓝宝石衬底和GaN外延层中的Mo杂质的含量，发现蓝宝石衬底中含有Mo杂质，含量约为10^-4（质量含量）；而在外延层GaN中没有检测到Mo杂质，即Mo杂质含量小于ppm级。由此可见，在目前的器件产业工艺要求下用廉价的Mo坩锅生长蓝宝石单晶是可行的。更多还原

【Abstract】 In this paper, the dislocation in Φ50mm CZ sapphire crystal had been observed by chemical etching with metallograph and SEM. Comparing the results which were obtained when the reagent and temperature and time varied ,we found the dislocation was displayed very clearly and accurately when we etch with KOH at 290℃ for fifteen minutes,which was the best condition.The defect and interface in sapphire and GaN were observed by AFM.We found that when the dislocation density in sapphire was lower thanl05/cm2, the dislocation density in GaN was 108~109/cm2and not linear with the dislocation in sapphire.The impurity of Mo in sapphire and GaN was measured by SEM XPS EPMA and UVF we found the Mo content in sapphire was 10-4,and the Mo content in GaN was lower than ppm. So it was concluded that low-cost Mo crucible is viable.更多还原