In this contribution, experimental facts about conduction and low frequency noise in TFTs are presented giving insight in the correlation between noise in n-type TFTs and their technology, electrical performances and reliability. The conduction and fluctuation mechanisms in polysilicon TFTs are described emphasizing the role of the grain boundary potential barriers. It is experimentally shown that the drain current is thermally activated. In addition, a similar transition between two regimes is observed in function of gate bias for both conduction and noise. Then, the noise temperature dependence investigation shows a thermal deactivation of the drain current spectra density. The relation between noise intensity and grain boundary potential barrier is detailed, allowing the extraction of pertinent parameters, which characterize the noise and potential barrier height variance. This information is useful to optimize the material growth and the process fabrication of the TFTs for improvement of the device performances.
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