Excimer laser induced crystallization of amorphous silicon on flexible polymer substrates

Laser crystallization of a-Si:H on PES, PET and AryLite™ polymer substrates is reported. For each material, the glass transition temperature Tg and the coefficient of thermal expansion have been evaluated, to determine the optimum deposition and crystallization processes conditions. 1000-Å thick intrinsic amorphous silicon films have been deposited on the substrates by Plasma Enhanced Chemical Vapour Deposition in the temperature range of 120-250°C. Dehydrogenation and crystallization have been obtained by high energy (10 J) XeCl pulsed excimer laser. The irradiation conditions have been varied to study their influence on the electrical and optical properties of crystallized material. Structural characterization has been performed by X-ray Diffraction. Increasing the radiation energy densities up to 220 mJ/cm2 crystallites sizes up to 750 Å have been obtained.