GaN外延衬底LiGaO2晶体的生长和缺陷

ＬｉＧａＯ２与ＧａＮ的晶格失配率只有０．２％，是一种很有潜力的蓝光衬底材料。通过多次实验，用提拉法生长了尺寸为１５×６０ｍｍ的高质量ＬｉＧａＯ２单晶。利用化学侵蚀、光学显微镜、透射电子显微镜对晶体中的缺陷进行了分析，研究了生长参数、原料化学配比对晶体质量的影响。ＬｉＧａＯ２晶体在〈１００〉方向生长速率最快，在〈００１〉方向上生长较慢。由于原料按非化学计量比挥发致使组份偏离，容易产生γ－Ｇａ２Ｏ３包裹物。包裹物和位错的形成具有一定的相互促进作用，往往形成平行于（００１）面的亚晶界。通过调整原料配比、生长工艺参数可克服上述问题。

Growth and Defects of LiGaO 2 Crystal Used for GaN Epitaxy

The lattice mismatch between LiGaO 2 and GaN is only 0.2%, so LiGaO 2 is expected to be a promising substrate for the epitaxy of GaN. In present work, large LiGaO 2 single crystal (φ15×60 mm) with high quality has been grown using Czochralski method . The crystalline quality was characterized by means of chemical etching, optical microscope and TEM. The influences of growth parameters on LiGaO 2 crystal quality were invetigated. The growth rate along 〈100〉 is the most rapid, that along 〈001〉 is lowest. γ Ga 2O 3 inclusions tend to emerge in LiGaO 2 crystal owing to the volatilization of Li 2O, therefore, a lot of dislocations were induced, which form the subgrain boundary parallel to (001) plane. High quality LiGaO 2 crystal can be obtained by using the charge with excess Li 2O and adopting appropriate growth parameters.