近化学计量比的HgCdTe薄膜表面处理方法

Surface Treatment Method of Near-Stoichiometric Ratio HgCdTe Film

本文采用X射线光电子能谱检测技术分别对溴-甲醇(Br_(2):Me)、溴-氢溴酸(Br_(2):HBr)和溴-氢溴酸-乙二醇(Br_(2):HBr:Eg)3种体系的腐蚀液处理后的HgCdTe表面状态进行了研究,结果表明这3种溴基腐蚀液均会造成HgCdTe表面富碲(Te^(0)),且富碲程度为(Br_(2):HBr:Eg)<(Br_(2):HBr)<(Br_(2):Me)。为了获得接近化学计量比的表面,一般采取先氧化富碲为TeO_(2)后腐蚀的方式去除表面富碲,然而,湿法腐蚀去除表面富碲的方法存在各种缺点。等离子体氧化具有氧化性强,工艺稳定,安全环保等优点,因此本文通过氧等离子体氧化Br_(2):HBr:Eg处理后的HgCdTe表面,进一步研究了盐酸、乳酸和氢氧化铵溶液腐蚀去除HgCdTe表面氧化物的情况,结果表明低浓度的盐酸能够较彻底地去除HgCdTe表面氧化物且不引入碳等其他污染物。在此接近化学计量比的表面制备的CdTe钝化膜与HgCdTe界面孔洞大小及数量显著减小,说明CdTe/HgCdTe界面的缺陷密度更低。

Surface components of HgCdTe(MCT)films were examined using x-ray photoelectron spectroscopy after etching with different solutions,including Br_(2):methanol(Br_(2):Me),Br_(2):HBr,and Br_(2):HBr:ethanediol(Br_(2):HBr:Eg).The surface degradation after etching by bromide-based solutions arises from the Te-rich element on the surface of HgCdTe,and the enrichment degree of Te is(Br_(2):HBr:Eg)<(Br_(2):HBr)<(Br_(2):Me).The wet-etch method is difficult to apply in eliminating Te-rich components to achieve a near-stoichiometric surface.In the commonly used method,oxidation is followed by corrosion.Plasma oxidation offers advantages,such as strong oxidation,stability,safety,and environmental protection.Therefore,oxygen plasma treatment has been introduced for various etchants to eliminate oxides,including hydrochloric acid,lactic acid,and ammonia.The results indicate that the use of low-concentration hydrochloric acid immersion generates a better effect without introducing any new dopants,and the defect density of the CdTe/HgCdTe interface decreases significantly after treatment.