The challenge in the compact modeling of Thin Film Transistors (TFTs) is to accurately reproduce all regimes of operation (leakage, subthreshold, and above threshold) and account for short channel and non-ideal effects. The models should be suitable for the device characterization and parameter extraction. The non-ideal effects (which might be specific to a particular TFT type) include mobility degradation at high gate biases, velocity saturation (in poly-Si TFTs), drain-induced barrier lowering, self- heating, effects of the series resistance, and the floating-body effects. The self-heating and kink effects might become important in short channel devices [1]). The unified and universal charge control models [2] that describe both the above and below threshold characteristics with one generalized charge control equation are the basic FET models that have the advantages of a better convergence (avoiding the binning problem) and a relatively small number of parameters (simplifying the parameter extraction). These models have been augmented with the AC models that account for the RC constants represented by the fractions of the channel resistances in series with the gate-to-source and gate-to-drain capacitances for reproducing the frequency dispersion. The non-linear contacts have been modeled as non-linear transmission lines and/or non-ideal diodes. [3] Such compact TFT models have been implemented in circuit simulators [3] and, with certain modifications, they are suitable for the simulation of amorphous Si, poly-Si, monocrystalline silicon, and even organic TFTs. [4] [1] L. Wang, T.A. Fjeldly, B. Iniguez, and M.S. Shur, Self-heating and Kink Effects in a-Si:H Thin Film Transistors, IEEE Trans. Electron Devices, Vol. 47, p. 387, February 2000 [2] T. A. Fjeldly, T. Ytterdal and M. Shur, `Introduction to device modeling and circuit simulation,' Wiley, NY 1997. [3] B. Iniguez, L. Wang, Z. Xu, T.A. Fjeldly and M.S. Shur, Short Channel AIM-Spice Models for Amorphous and Polysilicon Thin Film Transistors, in Future Trends in Microelectronics. The Road Ahead, John Wiley and Sons, 1999, p. 213 [4] P.V. Necliudov, M.S. Shur, D.J. Gundlach, T.N. Jackson, Modeling of organic thin _lm transistors of different designs, J. Appl. Phys., December 15 (2000) Figure 1