Stable amorphous-silicon thin-film transistors

Hydrogenated amorphous silicon, a-Si:H, prepared with the hot-wire chemical vapour deposition technique is incorporated in thin-film transistors (TFTs). High-quality TFTs are fabricated with this type of a-Si:H, which we deposited at a rate of 17 Å/s. TFTs with a current switching ratio of 5×105, a threshold voltage of 6.3 V, and an electron field-effect mobility in the saturation regime of 0.6 cm2/V s are obtained. These TFTs do not show any threshold voltage shift upon prolonged gate voltage application, in contrast to conventional a-Si:H TFTs. This has been achieved by optimizing the electronic properties of the hot-wire layer, and by optimizing the interface between the gate dielectric and the hot-wire layer.