Temperature dependence of the transfer characteristics of polysilicon thin film transistors fabricated by excimer laser crystallization

The transfer characteristics of polysilicon thin film transistors have been measured in the
temperature range from 400 to 80 K. The active layer has been made by excimer laser crystallization
of amorphous silicon. The devices show high field-effect mobility values ~.200 cm2/V s!, even at
low temperature. The electrical characteristics have been analyzed using a uniformly distributed
density of states ~DOS! model. The DOS has been derived using the values of the conductance at
various temperatures. Using the DOS derived from the ''temperature method,'' we have calculated
the transfer characteristics and the threshold voltage versus temperature, obtaining a very good
agreement with experimental data.