An advantage of laser crystallization over conventional heating methods is its ability to limit rapid heating and cooling to
thin surface layers. Laser energy is used to heat the a-Si thin film to change the microstructure to poly-Si.
Thin film samples of a-Si were irradiated with a CW-green laser source. Laser irradiated spots were produced by using
different laser powers and irradiation times.
These parameters are identified as key variables in the crystallization process. The power threshold for crystallization is
reduced as the irradiation time is increased. When this threshold is reached the crystalline fraction increases lineally
with power for each irradiation time.
The experimental results are analysed with the aid of a numerical thermal model and the presence of two crystallization
mechanisms are observed: one due to melting and the other due to solid phase transformation.