CURRENT CHARACTERISTICS OF POLYCRYSTALLINE THIN-FILM TRANSISTORS USING SPUTTERED SILICON FILMS

Polycrystalline thin-film transistors using sputtered Si films followed by high temperature crystallization have been fabricated and characterised. An analytical model has been proposed to explain the current-voltage characteristics of the TFT covering the sub-threshold, linear and saturation regions. The model assumes a spatial uniform distribution of trap states consisting of tail and deep states. The tail states have an exponential distribution within the bandgap, and the deep states are found to have a uniform distribution. The trap parameters can be easily extracted, and the model gives excellent agreement with experimental results.