Laser-enhanced crystallization of Ge and Si

Abstract

It is shown experimentally that laser irradiation of amorphous Ge and Si films results in a much larger nucleation rate and growth velocity than under thermal annealing conditions. In particular, the observed nucleation rate enhancement attains more than four orders of magnitude at temperatures around 400°C. Crystal dimensions are also much larger than under thermal annealing conditions. These data are interpreted as due to a combination of thermal effects (temperature, strains) and non-thermal mechanisms (laser-induced metastable states formation, recombination enhanced diffusion). All these mechanisms modify the parameters involved in the diffusion of the vectors of the amorphous to crystal transformation, namely the so-called dangling bonds.