Inversion/accumulation-mode polysilicon thin-film transistors: characterization and unified modeling

n- and p-channel enhancement-mode polysilicon thin-film transistors are characterized. The device performance is modeled with the use of an effective doping model. This enables a unified description of both n- and p-channel devices. The model is simple, analytic, and in satisfactory agreement with experimental data. The transconductance behavior is discussed in correlation with the grain boundary properties. The threshold voltage is shown to be determined by the trapped electrons and holes, respectively, and it changes appreciably depending on the gate and drain voltages