Au/p-CdZnTe欧姆接触的电学测量及界面特性分析

Electrical measurement and interface analysis of the ohmic contact on p-CdZnTe with electroless Au

采用化学镀金法在高阻p-CZT(CdZnTe)晶片表面制备Au电极,并用改进的圆环传输线模型(Ring-CTLM)测量了CZT电极的接触电阻,探讨了大气气氛下退火温度对CZT电极欧姆特性的影响。实验结果表明,200℃退火可以显著改善欧姆特性,使接触电阻率cρ显著减小,采用Ring-CTLM模型测得CZT与金电极接触电阻率为0.1524Ω.cm2。通过XPS分析了CZT与Au电极接触界面的成分,发现在Au/p-CdZnTe界面处形成了CdTeO3层,该界面层可起到载流子复合中心的作用,构建的新模型很好地解释了化学镀金法在p-CdZnTe晶片表面形成欧姆接触的机理。

Au ohmic electrodes were prepared by the reaction of gold chloride solution on p-CdZnTe surface,and the Ring-CTLM （ring circular transmission line model method） graph was gained by photolithography. The ohmic contact resistivities （ρc） of Au/p-CdZnTe contacts after annealing at different temperature were characterized by I-V measurement, ρc of contact after annealing at 200℃ was improved to be 0. 1524Ω · cm^2. From XPS analysis, CdTeO3 interface layer was found. This interface layer could act as the charge carrier recombination center, which can explain the ohmic contact mechanism of Au/p-CdZnTe.