INVESTIGATION OF INTRINSIC CHANNEL CHARACTERISTICS OF HYDROGENATED AMORPHOUS-SILICON THIN-FILM TRANSISTORS BY GATED-4-PROBE STRUCTURE

We use a new hydrogenated amorphous silicon (a-Si:H) device structure, the gated-four-probe a-Si:H thin-film transistor (TFT), to investigat e the intrinsic channel characteristics of inverted-staggered a-Si:H T FTs without the influence of source/drain series resistances. The expe rimental results have shown that, for the conventional a-Si:H TFT stru cture, the field-effect mobility, threshold voltage, and field-effect channel conductance activation energy have a strong dependence on a-Si :H thickness and TFT channel length. On the other hand, for the gated- four-probe a-Si:H TFT structure, these values are a-Si:H thickness and TFT channel length independent, clearly indicating that this new a-Si :H TFT structure can be effectively used to measure the channel intrin sic properties of a-Si:H TFTs. (C) 1998 American Institute of Physics.