Abstract
We investigated the mechanism after hundreds of bending parallel to the channel length on p-type poly silicon TFTs on metal foil substrate to discuss the device electronic characteristics and reliability. The extraction of the parasitic resistance、flat band voltage and trap density、threshold voltage、subthreshold slope and mobility were studied in detail for the mobility and current changing under bending condition. The reliability study of p-type polycrystalline silicon thin film transistors on metal foil fabricated by the ELC method under bending condition was investigated. The DC stress was utilized to simulate the operation of P-type poly-Si TFTs and to observe the degradation degree under bending condition. The result indicated threshold voltage shifted more badly in bending situation no matter under compressive or tensile condition than in plan situation. This phenomenon indicated the mobility under compressive strain with DC bias stress was better than tensile strain with DC bias stress. High quality films of n+ microcrystalline-Si:H was directly deposited on glass substrates at 150°C by ICP-CVD without any post-deposition re-crystallization. The crystallinity of n+ nc-Si:H evaluated from Raman spectra is about 91.35% and the grain size is about 20nm with growth rate about 5.33 nm/s. Sheet resistance values of lower than 103 Ω/sq were obtained and the resistivity was about 2.7 Ω•cm. The direct deposition of n+ nc-Si:H at low temperature may deserve more and more attention according to the cost down issue and ability for flexible substrate usage.