Calculation of the phase diagram of the GaInSb system in the (Ga +In)-rich region

Abstract

The phase diagram of the GaInSb system in the (Ga + In)-rich region was calculated using the model of regular associated solutions (RAS). The calculated liquidus temperature and solidus composition surfaces were examined by a goodness of fit test derived for an ( n + 1)-dimensional surface for which all the variables are subject to experimental errors. The results obtained using the RAS model were found to be in good agreement with the experimental data. It was also shown that the calculated phase diagram is compatible with the enthalpies of mixing measured for the GaIn, GaSb and InSb binary systems. Expressions were derived for the partial derivatives of the concentration of the various species in the liquid with respect to the temperature. Using these expressions it can be shown that, upon cooling, a liquid containing more (Ga + In) than Sb becomes super-saturated with regard to the atomic (uncombined) species and under-saturated with regard to the molecular species. Hence, the mechanism of crystallization proceeds via the addition of atomic layers to the surface of the crystal.