Growth mechanisms in laser crystallization and laser interference crystallization

The processes involved in the pulsed laser crystallization of amorphous silicon thin films were studied using transient reflection measurements. A model of the melting and solidification induced by the laser exposure, based on a one-dimensional calculation of the heat flow, was used to simulate the time-dependent reflectivity, yielding agreement with the experiments. Two laser beams interfering on the sample surface lead to the growth of long grains (up to 1.5 μm), with a well-defined orientation. We conclude that this lateral growth results from explosive crystallization combined with liquid phase growth.