Instability in radiatively melted silicon films.

Bosch and Lemons were first to report that in heating of silicon with a laser, the heated area can break up into small regions of solid and liquid. In this paper, the instabilities resulting from this unusual thermal situation have been analyzed. It is shown that a stable pattern can develop provided that the spacing between the solid and liquid is small enough. For a 1/2 micron thick layer of polysilicon on silica, the calculated stable spacing is less than about 10 micron, in accord with experiment.