Laser crystallization of thin a-Si films on plastic substrates using excimer laser treatments

The thin nanocrystalline silicon films were manufactured on polyimide substrate with Si3N4 buffer layer using XeCl excimer laser crystallization of a-Si films deposed with the use of low-temperature low-frequency plasma enhanced deposition technique. The thicknesses of Si films were 100 nm. The polyimide (temperature of plasticity up to 200 degreesC) was chosen as substrate due its good dielectric and mechanical properties. The structural properties of the films were studied using Raman scattering and high-resolution electron microscopy (HREM). Several regimes of pulse laser crystallization were used, the average size of obtained Si nanocrystals were modified from 2.5 up to 10 nm depending on crystallization regime. The sizes of nanocrystalline grains were estimated from Raman scattering data using approach of effective folding of optical vibration states in nanocrystals. The estimated from data of Raman scattering size of nanocrystals were in good agreement with direct data of HREM. The possibility of scanning laser treatments was shown. The obtained results are actual for manufacturing of polysilicon on plastic substrates structures for giant microelectronic applications (active matrixes of thin film transistors et. c.).