Field emission diodes with tungsten wedge cathode

A process technology and device characterization for vacuum microelectronic diodes with a lateral electron trajectory are described. The cathode for the diode devices is fabricated with successive deposition of Al-W-Ti:W utilizing DC magnetron sputtering. The aluminum film is partially sacrificed to achieve the necessary sharp tip of tungsten for field emission. The metals are deposited by DC magnetron sputtering followed by liftoff lithography and thermal annealing. Selected devices which are electrically characterized in 2 to 5*10/sup -9/ torr vacuum are compared with the Fowler-Nordheim-based model. The cathode-to-anode lateral spacing in these devices is 0.8 mu m. A maximum of 23- mu A current is obtained from the cathode of one of the devices investigated. Static electrical characteristics predicted by the Fowler-Nordheim relationship are compared with experimental data. >