GaAs单晶作为一种重要的LED衬底材料在光电器件中应用十分广泛, 但载流子浓度(C.C.)分布不均、杂质浓度过高等缺陷会严重影响相关器件的性能。为制备纵向载流子浓度分布均匀的掺硅HB-GaAs单晶, 本文探讨了单晶生长过程中熔区长度对纵向载流子浓度分布的影响。以高纯GaAs多晶为原料, 设定不同的拉晶温度曲线, 采用窄熔区技术进行晶体生长研究, 最终生长出C.C.值分布更均匀、位错密度低(EPD≤10 000 cm-2)的<111>向N型掺硅GaAs单晶。利用辉光放电质谱法(GDMS)和范德堡法霍尔效应测试对晶体进行了表征, 单晶纯度达到5N且无硼杂质沾污。

As an important Light Emitting Diode(LED) substrate material, GaAs single crystal has been widely used in optoelectronic devices, but the defects such as uneven distribution of carrier concentration (C.C.) and high concentration of impurities seriously affect the performance of corresponding devices. In order to prepare a Si-doped HB-GaAs single crystal with uniform longitudinal distribution of C.C., the influence of the melting zone length on the longitudinal distribution of C.C. during crystal growth was investigated. Using high-purity GaAs polycrystals as raw materials, setting different crystal pull temperature curves, and using narrow-melt zone technique for the crystal growth research, finally, N-type Si-doped <111> GaAs single crystal having a more uniform distribution of C.C. and lower dislocation density (EPD≤10 000 cm-2) was obtained. The crystal was characterized by glow discharge mass spectrometry (GDMS) and Vanderbilt method. The purity of the single crystal reaches 5N which stained without boron impurities.