环境湿度对VGF法半绝缘砷化镓单晶备料生长的影响研究

Impact of Environmental Humidity on VGF Semi-insulating Material Growth of Gallium Arsenide Single Crystal

利用垂直梯度冷凝法生长半绝缘砷化镓单晶的环境是一个密闭的真空系统,但是在备料过程中不可避免要受到周围环境的影响。通过除湿设备对环境除湿,分别在湿度为40%,±5%,和60%,±5%,时,使用等质量的多晶料、掺杂剂等材料进行备料实验研究。结果表明,环境湿度较大时备料,VGF生长出的半绝缘砷化镓单晶表面有凹坑甚至沟道,影响单晶直径,而备料系统中适当的含水量有助于生长过程的掺杂,当环境湿度较大时备料反而会降低砷化镓晶体生长时掺杂C的浓度,进而降低其半绝缘性能。

The growth of semi-insulating GAAS single crystals by vertical gradient condensation method is taken place in a closed vacuum system, which still cannot avoid the influence of environment in the process of material preparation. Based on environment dehumidification by relevant equipment, a study was carried out on the material preparation of polycrystalline,dopant and other materials with the same quality under the humidity conditions of 40%±5% and 60%±5% respectively.The results showed that when the environmental humidity is high, the surface of semi-insulating GAAS single crystals grown from VGF has pits and even channels, which affects the diameter of single crystals. However, the appropriate moisture content in the preparation system is in favor of the doping during the growth process. A higher humidity environment during material preparation will reduce the concentration of doped C during the gallium arsenide crystal growth, thereby lowering its semi-insulation performance.