Aluminum induced lateral crystallization of amorphous silicon thin films

A new process for low-temperature crystallization of amorphous Si (a-Si) films, metal-induced lateral crystallization (MILC), was developed. In our work, Al metal was adopted for the purpose of enhancing the crystallization of a-Si. The a-Si films right under the Al films were crystallized to the poly-Si films at the initial stage of annealing. These crystalline seeds were then grown laterally into Ai-free area without further nucleation (lateral crystallization), thus obtaining large-grained poly-Si films with no metal contamination. The crystallinity was examined by Raman spectroscopy and X-ray diffraction. The results show that during MILC, the lowest temperature of Al induced lateral crystallization is about 300 degrees C and the crystallinity was enhanced while the temperature increased. This low temperature contamination-free lateral crystallization phenomenon may be applicable to the low temperature fabrication of poly-Si TFTs on the glass substrates.