RELAXATION AND CRYSTALLIZATION KINETICS OF AMORPHOUS-GERMANIUM FILMS BY NANOSECOND LASER-PULSES

Relaxation and crystallization of amorphous germanium films on silicon are induced by nanosecond laser pulses. Real time reflectivity measur ements and Raman spectroscopy show that amorphous regrowth occurs upon melting and rapid solidification of the film because the thermal cond uctivity of the silicon substrate is high enough to extract the laser energy absorbed by the film in a very efficient way. The amorphous reg rown film is in a relaxed state when compared to the as-grown amorphou s material. Further pulses induce fast crystallization of the film. An increase of the melting threshold is found upon relaxation and crysta llization of the film.