1/f Noise in amorphous silicon thin film transistors: effect of scaling down

Abstract 1/f noise is investigated in thin film transistors as a function of gate geometry and film thickness. Two noise sources are present associated with the intrinsic channel and the access resistances. Intrinsic channel noise agrees with Hooge's theory and the value of αH (≈4×10−3) is independent of the device geometry. In order to characterize the noise in the access resistances a model is proposed. It describes accurately the later noise source versus gate width and film thickness. It is shown that only one parameter is necessary to model the experimental data. Finally the contribution of each noise source to the total channel noise is modelled, showing the important part due to the thickness of the a-Si:H film.