半绝缘砷化镓中本征缺陷的光学显微研究

Investigation of the native defects in LEC SI-GaAs by optical microscopy

本文利用光学显微技术系统分析热处理对液封直拉法生长的半绝缘砷化镓（LECSI-GaAs）中本征缺陷的影响。实验结果表明，晶体生长后的热处理可以影响砷沉淀的密度与分布。500℃热处理对As沉淀的密度无明显影响；真空条件下，在850-930℃范围内热处理AB腐蚀坑变浅，砷沉淀数量增加；真空条件下，高于1100℃热处理后，砷沉淀几乎消失。晶体中砷沉淀的密度会随热处理条件的不同而变化，本文对其机理进行探讨。

The effects of thermal annealing on the native defects in LEC SI-GaAs were studied by optical microscopy. The results showed that the thermal annealing could affect the density and distribution of the arsenic precipitates. The density and distribution of the arsenic precipitates can not be affected obviously at 500 ℃, Under vacuum conditions, AB etching pits become shallower, and the number of arsenic precipitates increases in the range of the 850-930 ℃. Under vacuum conditions, arsenic precipitates almost disappear after thermal annealing above 1100℃. The density of arsenic precipitates in SI-GaAs crystal changes with different thermal annealing conditions, the mechanism of the change was discussed.