1/f noise modeling in long channel amorphous silicon thin film transistors

1/f noise investigations in thin film transistors with long channel and thi n thickness of amorphous silicon film are presented. It is found that the n oise behavior follows the mobility fluctuation model in ohmic and saturatio n regimes, whereas in the subthreshold conduction, a quadratic law versus t he drain current is observed. The noise modeling is proposed taking into ac count the equations usually utilized for crystalline silicon metal-oxide-se miconductor field-effect transistors according to Hooge's theory. Moreover, the Berkeley Short-Channel Insulated Gate Field-Effect Transistor Model is adapted to predict the noise levels. Two noise parameters have been extrac ted: The first is used in the subthreshold region, whereas we show that the second, directly related to Hooge's parameter, is adequate to describe alo ne the noise in normal conduction up to the saturation. (C) 2000 American I nstitute of Physics. [S0021-8979(00)01403-1].