镓硼共掺对6英寸VGF法锗单晶电阻率均匀性的影响

Influence of Ga-B Co-Doping on the Resistivity Uniformity of 6 inch Ge Single Crystal by VGF Method

由于杂质分凝效应,镓掺杂垂直梯度凝固(VGF)法锗单晶的电阻率分布不均匀,理论上利用镓和硼分凝系数的差异,镓硼共掺工艺可以提升锗单晶电阻率均匀性。采用镓硼共掺工艺制备了6英寸(1英寸≈2.54 cm)VGF法锗单晶,对比分析了掺杂工艺对锗单晶电阻率均匀性的影响。当镓和硼杂质浓度分别为5.13×10^(18)cm^(-3)和0.67×10^(18)cm^(-3)时,在等径0~40 mm范围内轴向电阻率不均匀性为4.92%,等径0 mm和40 mm处径向电阻率不均匀性分别为1.63%和0.45%,与镓杂质浓度为5.13×10^(18)cm^(-3)的镓掺杂工艺相比,锗单晶头部的电阻率均匀性明显提升。当硼杂质浓度提高到1.89×10^(18)cm^(-3)时,镓硼共掺锗单晶头部电阻率均匀性变差。结果表明,适量硼掺杂的镓硼共掺工艺可以提升锗单晶头部电阻率均匀性。

The resistivity distribution of Ga-doped Ge single crystal by vertical gradient freeze(VGF)method is not uniform due to the impurity segregation effect.In theory,by using the segregation coefficient difference between Ga and B,the resistivity uniformity of Ge single crystal can be improved by Ga-B co-doping process.The 6 inch(1 inch~2.54 cm)Ge single crystals by VGF method were grown with Ga-B co-doping process,and the effects of the doping process on the resistivity uniformity were comparatively analyzed.When the Ga and B impurity concentrations are 5.13×10^(18)cm^(-3)and 0.67×10^(18)cm^(-3)respectively,the axial resistivity non-uniformity is 4.92%in the equal diameter range of 0-40 mm,and the radial resistivity non-uniformities at equal diameters of 0 mm and 40 mm are 1.63%and 0.45%respectively.Compared with the Ga doping process with a Ga impurity concentration of 5.13×10^(18)s cm^(-3),the head resistivity uniformity of Ge single crystal is significantly improved.When the B impurity concentration is increased to 1.89×10^(18)cm^(-3),the head resistivity uniformity of Ga-B co-doped Ge single crystal deteriorates.The results show that the Ga-B co-doping process with moderate B doping can improve the head resistivity uniformity of Ge single crystal.