Stress-induced width-dependent degradation of low-temperature polycrystalline silicon thin-film transistor

This study characterizes the stress-induced subthreshold degradation effect in low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs) formed using sequential lateral solidified (SLS) crystallization on a glass substrate. The SLS process is adopted to improve carrier mobility by increasing the grain size. The deterioration of the innate subgrain boundaries that are induced by channel hot-electron stress causes these transistors to exhibit double-hump subthreshold characteristics which become more prominent as the width of the channel increases. A physical theory and a proposed transistor network model accurately explain and predict the width-dependent subthreshold degradation characteristics of these stress LTPS-TFTs. (c) 2007 American Institute of Physics.