Abstract
Metal-induced crystallization method is one of the favorable non-laser crystallization methods for thin-film transistors in large-area displays. However, it is necessary to reduce metal contamination in the film to lower leakage current for the device applications. A new two-step crystallization method, consisting of a nucleation step by $AlCl_3$ vapor-induced crystallization and a grain growth step by a pulsed rapid thermal annealing, has been proposed to increase the grain size and reduce the residual metal contamination in crystallized poly-Si films. The grain size of the poly-Si film crystallized by the VIC + PRTA two-step crystallization process was as large as $70{\mu}m$. Furthermore, the Al concentration in the poly-Si film was reduced by two orders of magnitude from $1{\times}10^{20}cm^{-3}$ by VIC only process to $1.4{\times}10^{18}cm^{-3}$ by the two-step process. As a result, the minimum leakage current of poly-Si TFTs using the poly-Si film prepared by the two-step process was reduced from $1.9{\times}10^{-10}A/{\mu}m$ to $2.8{\times}10^{-11}A/{\mu}m$ at a drain voltage of 5 V, without carrier mobility degradation.
