Amorphous silicon thin film transistor fabricated at 125 °C by dc reactive magnetron sputtering

We deposit hydrogenated amorphous silicon-based thin film transistors using dc reactive magnetron sputtering at a substrate temperature of 125 °C, which is low enough to allow the use of plastic substrates. We characterize the structural properties of the a-Si:H channel and a-SiN_x:H dielectric layers using infra-red absorption, thermal hydrogen evolution, and refractive index measurements, and evaluate the electrical quality using capacitance-voltage and leakage current measurements. Inverted staggered thin film transistors made with these layers exhibit a field effect mobility of 0.3 cm²/V-s, a I_on/I_off ratio of 5×10⁵, a sub-threshold slope of 0.8 V/decade, and a threshold voltage of 3 V.