A mechanism was proposed for the formation of inhomogeneities during post-growth cooling or low-temperature annealing. This was based upon a diffusional instability in the interacting system, which included cations in lattice sites, Hg interstitials and cation vacancies. The principal features of the mechanism were that the vacancies followed local variations in alloy concentration and were always in local equilibrium, and that their concentration depended super-linearly upon the local composition. The uniform distributions of composition and of the native dopants became unstable under conditions which were likely to obtain at temperatures below 200C in samples that were enriched with Hg interstitials. It was shown that the instability could result in the formation of a so-called layered dopant profile, where the concentration of Hg interstitials varied by a factor of 2 to 3, while the variation in composition was of the order of 10%.

M.I.Vasilevskiy, E.V.Anda: Semiconductor Science and Technology: 1995, 10[2], 157-62