碲锌镉表面钝化层深度剖析及钝化工艺优化

Passivation composition analysis and passivation process optimization of CdZnTe

采用扫描电子显微镜(scanning electron microscopy,SEM)、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)和电流-电压(current-voltage,Ⅰ-Ⅴ)曲线等测试方法,分析了CdZnTe晶片两步溶液法钝化工艺参数对晶片的表面形貌、表面成分和电学性能的影响。研究发现,两步溶液法的最佳钝化时间为30 min,此时漏电流接近最小。CdZnTe钝化后经100℃、60 min的热处理,金相和SEM显示钝化层表面的形貌更为均匀致密,XPS深度剖析表明化学反应中间产物分解较为完全,TeO2含量增多,Ⅰ-Ⅴ测试显示热处理后漏电流减小较为明显,有效提高了探测器的性能。

The influence of different passivation time and annealing on the surface morphology,electrical properties and composition of CdZnTe is studied via scanning electron microscopy(SEM),current-voltage(Ⅰ-Ⅴ) and X-ray photoelectron spectroscopy(XPS).The result shows that the optimum passivation time for two-step passivation method is 30 minutes,and the leakage current is close to the minimum.After the wafers are annealed for 60 minutes at 100℃,metallography and SEM show that the surface morphology after heat treatment is to a more considerable degree in uniformity and density.XPS depth analysis shows that chemical reaction intermediate decomposition is relatively complete and that TeO2 content is increased.Ⅰ-Ⅴ test shows that the leakage current is reduced,which effectively improves the detector’s performance.