DETERMINATION OF THE DEFORMATION STATE OF HGSE ZNTE LAYERS/

High-resolution X-ray diffraction is commonly used to measure the misf it strain and to determine the unstrained lattice parameter of epitaxi al semiconductor layers assuming tetragonal distortion. A method is de veloped which links the measured inter-planar spacings to the deformat ion tensor without assumption of layer symmetry. For the system HgSe o n a thick ZnTe buffer layer deposited by MBE on GaAs substrate, the si x components of the reciprocal metric tensor of each layer are determi ned by a least-squares algorithm from a set of reciprocal lattice vect ors (131, 553). A principal-axis transformation of the calculated defo rmation tensor shows that the deformation nearly parallel to the [110] and [1(1) over bar0$] directions in the interface plane differs by mo re than 15%. This difference is a function of the epilayer thickness a nd reaches a maximum for layers slightly thicker than the critical thi ckness.