ANALYSIS OF ELECTRICAL CHARACTERISTICS OF POLYCRYSTALLINE SILICON THIN-FILM TRANSISTORS UNDER STATIC AND DYNAMIC CONDITIONS

Polycrystalline silicon TFT technology is rapidly emerging for large-a rea electronic applications, because of the relatively large mobility values of charge carriers with respect to the corresponding values in amorphous silicon. In contrast, because of the complex energy distribu tion of localized states within the energy gap, and the resulting spac e-charge effects, the TFT electrical characteristics are difficult to model, and a numerical approach is needed in order to better understan d the physical effects which influence the device performances. In thi s article we perform numerical simulations of TFTs at different temper atures under static and dynamic conditions and, by fitting experimenta l data, extract the energy distribution and the capture cross-section of the grain-boundary traps and the parameters of the impact-ionizatio n model. As opposed to single-crystal silicon SOI devices, we find tha t the TFT current and transconductance increase as temperature increas es. (C) 1997 Elsevier Science Ltd.