Relation Between Temperature and Solidification Velocity in Rapidly Cooled Liquid Silicon

Abstract

ABSTRACTA semi-empirical method to determine the undercooling-velocity relationship for laser induced melting is presented. The technique uses measurements of melt depth versus time to control numerical simulations, resulting in a map of the interface temperature as a function of time, and consequently as a function of the interface velocity. The results are independent of any model for the velocity-undercooling relationship. Results of the technique on simulated and experimental melt depth data are presented. Transient conductance data on 28 nanosecond 694 nm laser irradiation of silicon indicate an undercooling-velocity slope of 17±3 K/(m/sec) near the melting point. Picosecond optical transmission data show a much smaller slope.