Nonequilibrium segregation and trapping phenomena during ion-induced crystallization of amorphous Si

The segregation and trapping of Au at the moving crystal-amorphous Si interface has been measured. Epitaxial crystallization was induced by 2.5-MeV Ar-ion irradiation. The Au segregation is analogous to behavior at liquid-solid interfaces except that the interfacial segregation coefficient of 0.007 at 320 °C is independent of velocity between 0.6 and 6 Å/sec. The Au is trapped in crystalline Si at concentrations some 10 orders of magnitude in excess of equilibrium concentration.