Field-emission triodes with integrated anodes

A silicon microtriode where the gate and anode are fully integrated along w ith the cathode tip on the silicon substrate is proposed. The device can op erate in two modes: a normally on mode and a normally off mode. In the norm ally on mode, reported here, the anode is a suspended bimetallic layer of c hromium and gold above a sharp silicon tip, formed by the anisotropic etchi ng of silicon in potassium hydroxide solution. The gate, in the same plane as the anode, is formed of the same bimetallic layer and approaches from th e sides. The process requires only one mask and is extremely simple. Field emission was found between the anode and the cathode tip and, in three-term inal mode, the device was found to have gate control. The extrapolated gate pinch-off voltages for the two devices measured were -230 and -162 V at an anode voltage of 120 V. (C) 2000 American Vacuum Society. [S0734-211X(00)0 7502-8].