Recrystallization of Si on amorphous substrates by doughnut-shaped cw Ar laser beam

Abstract

Continuous single-crystal Si films longer than 600 μm over SiO2 have been produced with or without lateral epitaxial growth from bulk silicon seed by changing the mode structure of the cw Ar laser beam. The thermal profile of the laser spot is controlled by using a doughnut-shaped beam instead of usual Gaussian one to suppress competitive nucleation from side edges of the molten zone. The result indicates that the liquid-solid interface line profile is the most essential limiting parameter on the mechanism of regrowth.