Excess noise in polysilicon thin film transistors operated in kink regime

Low frequency noise in polysilicon thin film transistors (TFTs) has been investigated for different operating conditions. When the devices are biased in the linear regime, the 1/f noise can be ascribed to carrier number fluctuations. When the devices are biased above pinch-off, an anomalous current increase appears. Related to impact ionisation (the kink effect), with an associated excess noise. This excess noise can be attributed, in analogy with SOI-MOSFETs, to additional fluctuations relating to the parasitic bipolar transistor carrier transport, responsible for the enhancement of the anomalous current increase in polysilicon TFTs