GaAs/AlGaAs分子束外延材料的X射线双晶形貌观察

本文介绍了用非平行非对称(+、-)双晶X射线形貌术研究Ⅲ—Ⅴ族化合物外延晶体的设置和原理。分析了外延后形成的弯曲样品造成的衍射效应。对分子束外延(MBE)法生长的GaAs/AlGaAs衬底和外延层分别进行了X射线形貌术观察。讨论了外延层中存在的失配位错、生长小丘、沾污和局部微差取向等缺陷。对位错的组态和来源进行了初步分析。本实验结果也表明,有应变超晶格过渡层的MBE法对生长优质的GaAs/AlGaAs外延片是有利的。

OBSERVATION OF X-RAY DOUBLE CRYSTAL TOPOGRAPHY ON GaAs/AlGaAs MBE GROWN LAYERS

X-ray double crystal topography method with non-parallel asymmetrical (+, -) setting and the study on GaAs/AlGaAs epitaxial crystal are given in this paper. The diffracted effects of bending crystal plane resulted from epitaxy are analysed.From the topographies of substrate and epitaxial layers on MBE, misfit dislocations, line dislocations, growth hillock, defects from pollution and misorientation are discussed.The origination and developement of defects and dislocations are explained from the processes and principle. It is found that the MBE growth GaAs/AlGaAs epitaxy can be improved by the insert of a serial strain super lattices.