Gettering in Large-Grained Thin Polycrystalline Silicon Films on Glass Substrate

Abstract

Large-grained polycrystalline silicon (poly-Si) films on a glass substrate are good candidate materials for fabricating poly-Si thin-film transistors (TFTs) and poly-Si solar cells. The gettering of metal impurities in thin poly-Si films is one of the key techniques for realizing high-performance, high-reliability, and high-efficiency TFTs and solar cells. In this study, the gettering of large-grained thin poly-Si films with a thickness of 100 nm containing Ni impurities was studied. A large-grained Ni-doped thin poly-Si film was fabricated on a glass substrate by Ni-induced solid phase crystallization (SPC) followed by cw green laser recrystallization. The grain size of the poly-Si film was 1 ×10 µm2. The behavior of Ni impurities in the large-grained thin poly-Si film was evaluated by scanning transmission electron microscopy (STEM), STEM energy-dispersive X-ray spectroscopy (STEM–EDX), and electron diffraction (ED) analysis. It was observed that Ni was stabilized through the formation of nickel-disilicide (NiSi2) at the triple junction during low-temperature device fabrication.