VGF法半绝缘GaAs单晶EL2浓度优化研究

Study on EL2 Concentration Optimization of VGF Semi-insulating Gallium Arsenide Single Crystal

为了获得高电阻率及迁移率的半绝缘GaAs单晶材料,采用经高压及水平合成不同工艺制得的GaAs多晶料,进行垂直梯度凝固(VGF)法半绝缘GaAs单晶生长,测试和分析相应单晶片的EL2浓度、C浓度及电阻率、迁移率等性能参数,对比和分析了GaAs化学计量比的不同对单晶EL2浓度及电学参数的影响,经多炉次实验,确定出GaAs单晶电阻率>1×10^8Ω·cm及迁移率>5×10^3 cm^2/(V·s)时C浓度及EL2浓度的合理范围,并据此结论,指导MBE外延用半绝缘GaAs单晶生长,保证了半绝缘GaAs单晶在满足高电阻率和迁移率的同时,具有较高的重复性和一致性。

In order to obtain the SI-GaAs material with high resistivity and mobility,the VGF(Vertical Gradient Freeze)method was used to grow the SI-GaAs single crystal which the polycrystalline for growth were come from the high pressure synthesis method and the HB synthesis method.Then the concentration of EL2,carbon and resistivity,mobility of the corresponding single crystal chips were tested and analyzed,and the influence of the different GaAs stoichiometric on concentration of EL2 and electrical parameters of the single crystal was compared and analyzed.After several times of experiments,the concentration reasonable scope of EL2 and carbon under the condition of the resistivity greater than>1×10^8Ω·cm and the mobility greater than 5×10^3 cm^2/(V·s)were determined.Finally,the experiment conclusion was used to guide the single crystal growth of SI-GaAs which used for MBE epitaxial growth,and what’s more,realizing the crystal growth having a great repeatability and consistency on high resistivity and mobility.