CRYSTAL DEFECTS AND INTERDIFFUSION BEHAVIOR OF HG1-XCDXTE (100)CDTE EPITAXIAL LAYERS GROWN BY CHEMICAL-VAPOR TRANSPORT/

Crystal defects of chemical vapor transport grown Hg1-xCdxTe on (100) CdTe structures have been investigated using chemical etching, wavelen gth-dispersive spectroscopy, x-ray rocking curve, and scanning electro n microscopy methods. The results indicate that the origin and spatial distribution of the misfit dislocations can be attributed to both the lattice parameter misfit and the inevitable interdiffusion occurring between the substrate and the epitaxial layer. It is proposed that the interdiffusion of Hg along the [($) over bar 100] direction is enhanc ed by dislocation channels and other defect cores along or near this d irection owing to defects on the initial surface of the CdTe substrate . The results indicate that the subgrain boundaries in Hg1-xCdxTe are caused by slight misorientation of the lattices and polygonization of the defects during epitaxial layer growth, and by the propagation of t he subgrain boundaries existing in the CdTe substrate.