p-Channel Amorphous Silicon Thin-Film Transistors with High Hole Mobility

The problem of low drift mobility of holes in hydrogenated amorphous silicon (a-Si:H) has been solved by controlling the hydrogen content in the film. A-Si:H films with low hydrogen content have been prepared by the radical-controlled method in which the glow discharge of the mixture of SiF 4 and H 2 is used and the residence time of the reactant species is controlled. A prototype MOSFET demonstrates a hole mobility of 0.12 cm 2 /Vs and an electron mobility of 0.24 cm 2 /Vs, suggesting the feasibility of the a-Si CMOS circuit.