We deposited hydrogenated amorphous silicon-based thin film transistors using dc reactive magnetron sputtering at a substrate temperature of 125 °C. We characterize the structural properties of the a-Si:H channel and a-SiNx:Hdielectric layers using infra-red absorption, thermal hydrogen evolution, and refractive index measurements, and evaluate the electrical quality using conductivity, capacitance–voltage, and leakage current measurements. Inverted staggered thin film transistors made with these layers exhibit a field effect mobility of 0.3cm2/V s, aIon/Ioffratio of5×105, a subthreshold slope of 0.8 V/decade, and a threshold voltage of 3 V. ©1997 American Institute of Physics.