A transmission electron microscopic study was made of the initial nucleation layers in the 2-step growth of CdTe, on 2 off-(001) GaAs substrates, using metalorganic chemical vapor deposition. In the case of substrates which had been degreased and etched in the usual manner, the initial deposits were oriented with their axes parallel to those of the substrates and the defects were distributed isotropically. However, initial deposits which were grown on substrates that had been prepared by thermal etching at 545 to 585C contained both (001)- and (111)-oriented grains. When these polycrystalline initial deposits were heated to the bulk growth temperature, epitaxial re-growth occurred. This produced a monocrystalline film with a very distinctive anisotropic defect microstructure, with stacking faults and a mixture and 60-type and 90-type misfit dislocations parallel to the off-cut axis and sub-grain boundaries and with 90-type misfit dislocations in the orthogonal direction. All of the 60-type misfit dislocations, and most of the stacking faults, lay on the (111) plane and produced a rotation of 5 to 8, between the substrate and deposit, about the off-cut axis. The results were explained in terms of differences, in the resolved shear stress, which occurred as secondary defects were introduced during re-growth.

T.T.Cheng, M.Aindow, I.P.Jones, J.E.Hails, D.J.Williams: Journal of Crystal Growth, 1995, 154[3-4], 251-61