位错对布里奇曼HgCdTe体晶结构完整性的影响

本文根据Ｘ射线形貌相、扫描电镜和金相显微镜的实验结果和有关位错、相图的理论，分析了位错和亚晶界、亚晶界和Ｘ射线形貌相的关系以及住错对布里奇曼技术生长的ＨｇＣｄＴｅ体晶结构完整性的影响。因位错降低能量的要求，ＨｇＣｄＴｅ体晶中的密度位错要形成亚晶界和三维位错网络等亚结构。在Ｘ射线形貌相中，亚结构的取向衬度是比位错直接象更强的成象机构。正常凝固长晶过程中ＨｇＣｄＴｅ材料的组分要变化，并使其固液界面的温度梯度也发生相应变化，由此引入的热应力在结晶过程中会在ＨｇＣｄＴｅ晶体中产生高密度位错。位错形成的亚晶界和三维位错网络等亚结构严重破坏了ＢｒｉｄｇｍａｎＨｇＣｄＴｅ体晶结构完整性，这使其Ｘ射线形貌相往往不好。

INFLUENCE OF DISLOCATIONS ON PERFECTION OF HgCdTe BULK CRYSTALS GROWN BY BRIDGMAN TECHNIOUE

In the paper influence of dislocations on perfection of HgCdTe bulk crystals grown by Bfdgman technique were analyzed based on the experimental re-sults of X-ray topography, SEM,optical microscope and the theories of disfocation and phase diagram. Owing to effect of composition segregatfon, composition devia-tion of HgCdTe generated in a crystallizing process of normal solidmcation makes temperature gradient changes in the solid-liquid interface. High density dislocations in HgCdTe bulk crystals result from thermal stresses produced by the temperature gradient changes. Dislocations move and form substructures such as three-dimen-sion dislocation networks and subgrain boundaries. It was these substructures that influence on perfection of HgCdTe bulk ctystals grown by Bridman technique.