Noise performance of polycrystalline silicon thin-film transistors made by sequential lateral solidification

Abstract

Low-frequency noise in polycrystalline silicon (polysilicon) thin-film transistors (TFTs), made using the sequential lateral solidification (SLS) technique, has been investigated. Two types of devices have been analyzed: SLS polysilicon TFTs, where the noise is dominated by the carrier number fluctuations, and extended grain polysilicon TFTs, where an excess noise was present for low drain currents. The noise induced by carrier number fluctuations was seen to scale, in both types of devices, with the inverse of the channel area, as expected from the theory. The excess noise was explained considering the mobility fluctuations induced by the scattering with low angle grain boundaries present in the extended grain polysilicon.