Dispersive charge injection model for a-Si:H/a-SiO2 Thin-Film Transistors instability

Bias stress measurements at different temperatures and stress voltage have been performed on a-Si:H thin-film transistors, where very thin ( 18 nm) plasma deposited a-SiOr was used as gate insulator. The data are explained on the basis of dispersive charge injection into the first 2-3 nm of the gate insulator. According to the proposed model a new functional form for the threshold voltage shift kinetics is deduced and a very good agreement with the experimental data is found.