Deep Analysis of the Geometric Component in Charge Pumping of Polycrystalline Silicon Thin-Film Transistors

In this paper, we model the geometric component in a charge pumping (CP) technique of polycrystalline silicon thin-film transistors (poly-Si TFTs). This model is based on both remaining carrier types when the device transits from accumulation to inversion and vice versa. Therefore, it depends on gate length (L) and width (W) as well as on gate signal rise (t_f) and fall time (tf). The proposed model shows good agreement with the experimental data. We have shown that the geometric component due to the remaining carriers, when poly-Si TFT transits from inversion to accumulation, is very small compared with that due to the transition from accumulation to inversion. Consequently, a new analytic CP model, depending on gate width, is developed for n-channel poly-Si TFT.