Transient nucleation following pulsed-laser melting of thin silicon films

Thin Si films on thermally grown SiO{sub 2} layers were completely melted by pulsed-laser irradiation. The molten films cool very rapidly ({gt}10{sup 9} K/s) until bulk nucleation initiates solidification. The quench rate was varied by changing the thickness of the Si or the SiO{sub 2} layers. For quenches below {similar to}10{sup 10} K/s the supercooling prior to nucleation was constant and {similar to}500 K; however, for more rapid quenches, the supercooling increases significantly. This increase is attributed to embryo distributions that fall out of steady state during rapid quenches.