A Comparison of Semiconductor Models for the Study of Liquid Phase Epitaxy

The phase behavior of silicon is studied using the Modified Embedded Atom Method (MEAM) proposed by Baskes, Nelson and Wright. We find this model to quantitatively reproduce aspects of both the solid and liquid phases with an accuracy comparable to the widely-used Stillinger-Weber (SW) potential, thus providing an opportunity to examine the consistency of results obtained previously using the SW model. Although the models are very different, they both produce solid-liquid interfaces on both silicon (100) and (111) which have very similar morphologies. We find that the MEAM predicts the melting point of silicon to be 1445K, or 14% lower than the experimental value. The model also predicts the heat of melting to be 34.9 kJ/mol, 45% lower than the experimental value of 50.6 kJ/mol, and a liquid density which is 5.4% larger than that of the solid at the melting point, which is the density ratio found by experiment. The liquid density is found to be too low with respect to experiment. We also suggest a correction which might be applied to the MEAM model to improve its description of the liquid phase.