Effect of Ni silicide density on electrical performance of silicide-induced crystallized polycrystalline silicon thin-film transistors

The electrical performance of low temperature polycrystalline silicon (LTPS) thin-film transistors (TFTs) fabricated by silicide-induced crystallization (SIC) is greatly affected by metal contamination such as Ni silicide. In this paper, the effect of Ni silicide density on the SIC poly-Si TFTs is investigated by in-situ Ni silicidation at room temperature, 100°C, 200°C, and 300°C, respectively. It was observed that grain size of fully crystallized polycrystalline silicon (poly-Si) decreased with the increase of in-situ silicidation temperature. This is due to an increase in the density of nucleation sites for crystallization. As a result, grain boundaries and interface trap-state densities were significantly increased and electrical properties such as subthreshold slope, on-state current and field effect mobility were drastically degraded.