Preparation of nanocrystalline silicon films by excimer-laser-induced crystallization

Abstract

Excimer laser-induced crystallization (ELC) technique has been used to prepare nanocrystal silicon (nc-Si) from amorphous silicon (a-Si) thin films on silicon or glass substrate. The a-Si films without hydrogen grown by pulsed laser deposition (PLD) are chosen as precursor to avoid the problem of hydrogen effluence during annealing. The analysis has been performed by scanning electron microscopy (SEM), Raman scattering spectroscopy and high-resolution transmission electron microscopy (HRTEM). Experimental results show that the silicon nanocrystals can be formed by laser annealing. The growth characters of nc-Si are strongly dependent on the laser energy density. It is shown that the volume of melted Si essentially predominates the grain size of nc-Si, and the surface tension of crystallized silicon is responsible for the mechanism of nc-Si growth