Stress effect on aluminum-induced crystallization of sputtered amorphous silicon thin films

This study emphasizes the important role of film stress in aluminum-induced crystallization (AIC) of sputtered amorphous silicon (a-Si). a-Si/Al/glass stacking structures with various a-Si/Al thickness ratios were prepared to provide different film stresses for systematical study of the film stress effect. Results showed that the existence of film stress tended to deteriorate the crystallization tendency of the AIC of a-Si. To further investigate the importance of the film stress effect, an a-Si(2000 Angstrom)/Al(500 Angstrom)/glass sample with a low film stress of 0.53 Mpa was prepared and annealed. It was found that the release of film stress in consuming thermal energy during the thermal annealing process occurred before the metal enhancement effect came to effect. From discussions, it was also suggested that the low film stress, large concentration gradient and low activation energy of metal silicide formation would provide greater enhancement for metal-induced crystallization.