Interfacial atomic transport in the nucleation of crystalline silicon from the melt

Observations of liquid supercooling achieved prior to solidification of rapidly quenched Si thin films as a function of quench rate are examined in terms of a numerical model for transient nucleation, which allows estimation of the kinetics for the transfer of atoms to and from crystalline clusters. The process is found to be thermally activated with an activation energy of 1.09 ± 0.05 eV/atom. This differs appreciably from previous estimates for the activation energy for planar growth of crystalline Si (≈0.3 eV) and possible reasons for this discrepancy are discussed. © 1991.