SOLIDIFICATION KINETICS IN SIGE ALLOYS

The solidification kinetics of SiGe alloys, modeled by the Stillinger- Weber potential, are investigated using nonequilibrium molecular-dynam ics computer simulation techniques. Interface response functions and s olute redistribution at the regrowing solid/liquid interface are inves tigated. The maximum crystallization velocity of SiGe alloys is found to decrease below the pure component values, in agreement with the res ults of explosive crystallization measurements. The results of solidif ication velocity versus interface temperature (i.e., one of the interf ace response functions) obtained from the simulation for SiGe alloys c ompare well, in most cases, with Aziz's continuous growth model assumi ng short-range diffusion-limited growth. Mutual trapping of Si in Ge a nd Ge in Si is found in both Si-rich and Ge-rich alloys, in agreement with Aziz's solute trapping theory and with experiment.