中文摘要：

采用坩埚下降法生长了LED用硅掺杂〈511〉取向的GaAs晶体。选用带籽晶槽的PBN坩埚作为生长容器,密封在石英安瓶中以防止生长过程中As蒸汽挥发。研究了掺杂工艺、固液界面形貌和生长缺陷。结果表明：孪晶化是硅掺杂GaAs晶体生长的主要问题。探讨了孪晶形成机理,优化了生长工艺,成功获得了直径2英寸高质量的硅掺杂GaAs晶体,双摇摆曲线显示所得晶体的FWHM为40 arcsec。

英文摘要：

Si-doped 〈511〉orientation GaAs crystal was grown by Bridgman method.PBN crucible with a seed well was used and quartz ampoule was adopted to protect the evaporation of As in the process of growth.The doping technology,solid-liquid interface morphology and growth defects were investigated.The twinning was a crucial problem for the pulling-down growth of Si-doped 〈511〉 GaAs crystal.The formation mechanism of the twins was suggested and the growth parameters were optimized.2-inch Si-doped GaAs crystal has been grown successfully and X-ray rocking curve showed that FWHM was about 40 arcsec.