Current DLTS Measurements on Poly-Si Thin Film Transistors

Polycrystalline-silicon thin film transistors have been assessed using current based deep level transient spectroscopy. A continuous distribution of states through the band gap was observed. Analysis suggested the density increased rapidly toward the conduction band edge indicating the presence of tail states. After annealing at 450°C the density of states increased over a large range of the band gap, from mid gap to ~0.1eV below the conduction band.