Electrolyte electroreflectance in the characterization of HgCdTe heterostructures

摘要

We have used the technique of electrolyte electroreflectance (EER) coupled with electrochemical etching to profile through epitaxial layers and heterostructures of Hg1minus;xCdxTe. The need for proper electrochemical control during EER measurements is discussed. The resolution achieved in both composition, Dgr;x=plusmn;0.002, and etch depth, plusmn;30 Aring;, has made possible the observation of the variations in composition at the ambient/epilayer, epilayer/substrate, and highhyphen;x/lowhyphen;xinterfaces. Good correlations of the profiles observed have been obtained with secondary ion mass spectroscopy, electron dispersive xhyphen;ray diffraction, and Rutherford backscattering measurements. The variation of the broadening parameter Ggr; at these interfaces is also discussed.