The Sub-Threshold Characteristics of Polysilicon Thin-Film-Transistors

It is shown that the sub-threshold characteristics of polysilicon transistors are well described by a model which assumes an exponential gap state density, similar to the ones used for hydrogenated amorphous silicon. The model leads to analytical expressions that give a very good fitting of the experimental data. In contrast, a model based on a simple monoenergetic trap level can in no way account for the observed I D-V G characteristics.