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

1/f noise is investigated in thin film transistors as a function of gate ge ometry and film thickness. Two noise sources are present associated with th e intrinsic channel and the access resistances, Intrinsic channel noise agr ees with Hooge's theory and the value of alpha(H) (approximate to 4 x 10(-3 )) is independent of the device geometry. In order to characterize the nois e in the access resistances a model is proposed. It describes accurately th e 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 fi lm. (C) 1999 Elsevier Science Ltd. All rights reserved.