A hydrogenated amorphous silicon field-effect transistor suitable for digital and analog applications is described. The device consists of a p+-i-n- junction, with the drain and source contacts connected to the n- layer and the control gate electrode to the p+ layer. As in the corresponding crystalline junction field-effect transistor, the channel resistivity is modulated by the gate voltage. The selection of the thickness of the intrinsic layer and the doping and thickness of the n layer is critical for correct operation of the device. A device with a well defined triode and saturation region was manufactured. A transconductance of 1.5×10-6 A/V at VDS=25 V was achieved. This value is comparable to that of state-of-the-art thin-film transistors. © 2000 American Institute of Physics.