It was found that the surface stoichiometry which was maintained during the first 5 monolayers of epitaxial growth could have an appreciable effect upon the stacking fault concentration in 2-thick epilayers. In particular, it was possible to decrease the stacking fault concentrations to levels which were of the order of 104/cm2. This was comparable to the stacking fault concentration in the ZnSe substrates which were used for epitaxy. The reduction was achieved by selecting a suitable delay time; such as about 30s for a substrate temperature of 300C, during the alternate element exposure growth phase. This delay time was the time which elapsed between the closing of the Se shutter and the opening of the Zn shutter. It was shown that the surface stoichiometry (Zn/Se ratio) could be tailored during the delay phase because Se thermal desorption occurred at the growth temperature. This occurred in a controlled fashion from an initially Se-terminated surface, and it was suggested that the selection of an optimum delay time which corresponded to the attainment of a near-stoichiometric surface resulted in the growth of low stacking-fault material.

M.H.Jeon, L.C.Calhoun, B.P.Gila, M.H.Ludwig, R.M.Park: Applied Physics Letters, 1996, 69[14], 2107-9