Using Phosphorus-Doped alpha-Si Gettering Layers to Improve NILC Poly-Si TFT Performance

Abstract

Ni-metal-induced lateral crystallization (NILC) has been utilized to fabricate polycrystalline silicon (poly-Si) thin-film transistors (TFTs). However, the current crystallization technology often leads to trapped Ni and NiSi(2) precipitates, thus degrading device performance. In this study, phosphorus-doped amorphous silicon (p-alpha-Si) and chemical oxide (chem-SiO(2)) films were used as Ni-gettering layers. After a gettering process, the Ni impurity within the NILC poly-Si film and the leakage current were both reduced, while the on/off current ratio was increased. This gettering process is compatible with NILC TFT processes and suitable for large-area NILC poly-Si films.