Modeling of the static and dynamic behavior of hydrogenated amorphous silicon thin-film transistors

This article reports on physically based models for hydrogenated amorphous silicon (a-Si:H) inverted staggered thin-film transistors (TFT), which accurately predict both the static and dynamic characteristics of the TFT. The model is implemented in VerilogA hardware description language, which comes as a standard feature in most circuit simulation environments. The static model includes both forward and reverse regimes of operation. The model for leakage current takes into account the physical mechanisms responsible for the source of the reverse current, viz., the formation of the conducting channels at the back and front a-Si:H/a-SiNx:H interfaces and their relative dominance at different bias conditions. The dynamic model includes the different charge components associated with the tail states, deep states, interfaces, and traps and their associated time constants. Good agreement between modeling and experimental results is obtained. (C) 2002 American Vacuum Society.