HgCdTe材料的溴-甲醇抛光工艺研究

Study on Bromine-Methanol Polishing Process of HgCdTe Wafers

碲镉汞(HgCdTe)红外探测器制备中的化学-机械抛光工艺会在碲镉汞材料表面形成一定深度的损伤层。用溴-甲醇化学机械抛光取代溴腐蚀工艺,有效地降低了抛光过程所产生的表面损伤。在溴-甲醇抛光工艺中,可变参数有溶液的浓度比、抛光时间、转盘转速等,不同的参数组合对于抛光效果有不同的影响,经过正交试验可以以较少的试验次数高效经济地得到最佳的溴-甲醇抛光工艺参数组合。以该优化参数进行抛光所得到的碲镉汞材料通过XRD测试以及Ar+刻蚀后表面形貌的测试表明,HgCdTe晶片表面剩余损伤大大减小。

The traditional chemo-mechanical polishing process leaves damages on the surface of the MCT wafers to a certain depth in the production of HgCdTe infrared detectors.Chemical etching can reduce some of those damages,however leaves a rough surface.Chemo-mechanical polishing with bromine-methanol can reduce the damage more effectively,produce stoichiometric MCT surface and increase the minority carrier lifetime while the surface is smooth and mirror-like.There are three variable parameters in bromine-methanol polishing which are volume ratio of bromine-methanol,polishing time and rotating rate of the turntable.Different parameters will make different polishing effect.Orthogonal experiment can present the best polishing parameters more effectively and economically with fewer experiments in quantity.The MCT wafers were polished with the optimized parameters and then exposed to XRD measurement.The XRD results show that the damages are removed effectively.The morphology of the surface after Ar＋ ion etching affirms the XRD results.