A simple procedure to extract the threshold voltage of amorphous thin filmMOSFETs in the saturation region

A technique is presented to extract the threshold voltage of amorphous thin film MOSFETs in the saturation region. The technique is proposed because t hreshold voltage extraction in amorphous TFTs is different, and in general more complex, than in conventional crystalline bulk devices, since these TF Ts exhibit several notable dissimilarities inherent to their characteristic s. The saturation drain current follows an m power-law type dependence on g ate bias, with an m different from the conventional value of 2. Additionall y, a plot of the saturation current as a function of gate bias does not rev eal the existence of an inflexion point. The method presented, which extrac ts the value of the power-law parameter rn as well, is based on the use of an auxiliary operator that involves the integration of the drain current as a Function of gate voltage. The technique was tested and its accuracy veri fied using the measured characteristics of an experimental n-channel a-Si:H thin him MOSFET. (C) 2001 Published by Elsevier Science Ltd.