Ultrarapid crystal growth and impurity segregation in amorphous silicon annealed with short Q-switched laser pulses

Very short Q-switched laser pulses have been used to produce especially high-speed crystal growth in ion implanted, amorphous Si layers. This is shown to occur in an unstable, explosive manner which can give pronounced lateral modulation of layer structure. Novel phenomena relating to impurity segregation and cell formation in amorphous Si are also presented. These provide strong evidence that amorphous Si melts to form an undercooled, normal, low viscosity liquid and that the amorphous phase itself is not a glassy state.