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GaN外延衬底LiGaO2晶体的生长和缺陷
Growth and Defects of LiGaO 2 Crystal Used for GaN Epitaxy
【摘要】 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。
【Abstract】 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.
【Key words】 LiGaO 2 crystal; crystal growth; epitaxy substrate; GaN; defect.;
- 【文献出处】 光学学报 ,ACTA OPTICA SINICA , 编辑部邮箱 ,1998年04期
- 【分类号】O78
- 【被引频次】4
- 【下载频次】106