不同Te掺杂量对InSb晶体性能的影响

Influence of Te doping concentration on the properties of InSb crystal

InSb原料因含受主杂质,制备出的InSb晶体通常呈P型特性,其迁移率低无法满足低温(77 K)时红外探测器需求。为了获得高迁移率特性,通过直拉法(Cz)生长了不同Te掺杂量的InSb∶Te晶体。利用霍尔测试仪测量晶体电学特性,结果表明,InSb∶Te晶体在77 K下的导电类型为N型。随着Te掺杂浓度从10^(16) cm^(-3)增加到1018 cm^(-3),电阻率从10^(-1)Ω·cm减小到10^(-4)Ω·cm,迁移率从103 cm^(2)·V^(-1)·s^(-1)增加到10^(4) cm^(2)·V^(-1)·s^(-1)。利用拉曼光谱仪、X射线衍射仪和傅里叶变换红外光谱仪对晶体的结晶质量和光学性能进行测试。结果表明,与非掺杂InSb晶体相比,Te掺杂使晶体半峰宽(FWHM)增大,透过率降低,带隙变宽,吸收截止波长向短波方向移动,Te掺杂会对拉曼峰强度产生影响。当Te掺杂浓度为6×10^(16) cm^(-3)时,获得最优的迁移率为6.95×10^(4) cm^(2)·V^(-1)·s^(-1),晶体半峰宽为0.51°,吸收截止波长为7.5μm。

InSb crystals prepared from undoped InSb raw materials with the acceptor impurities usually have P-type characteristics and its low mobility cannot meet the demand of infrared detectors at 77 K.In order to obtain high electron mobility,InSb crystals doped with different Te concentrations were grown by the Czochralski method.The electrical properties of the crystals were characterized by Hall effect.The results indicate that the conductivity type of InSb∶Te crystal is N-type at 77 K.With the concentration of Te increases from 10^(16) cm^(-3) to 1018 cm^(-3),the resistivity decreases from 10^(-1)Ω·cm to 10^(-4)Ω·cm and the mobility increases from 103 cm^(2)·V^(-1)·s^(-1) to 10^(4) cm^(2)·V^(-1)·s^(-1).The optical properties and crystallization of InSb crystals were characterized by XRD,FTIR and Raman Spectra.Compared with undoped InSb crystal,Te doping resulted in an increase of the FWHM,with reduced transmittance and broaden band gap,as well as the shift of the absorption cut-off wavelength toward the shortwave direction.Meanwhile,Te doping could affect the intensity of Raman peak intensity.When the Te doping concentration is 6×10^(16) cm^(-3),the optimized mobility is 6.95×10^(4) cm^(2)·V^(-1)·s^(-1),the FWHM is 0.51°and the absorption cut-off wavelength of crystal is 7.5μm.