Fabrication of iridium field emitter arrays

Iridium field emitter arrays were fabricated using Spindt tip process. Ir field emitter cones show an aspect ratio of 0.95, slightly less than Mo field emitter arrays fabricated using the same microfabrication process. When compared to the Mo field emitter arrays, the current-voltage characteristics of the Ir arrays were found to scale with the work function difference between Ir and Mo. Under ultrahigh vacuum conditions, the emission current stability of the Ir arrays measured over 180 h was found to be similar or slightly better than the emission stability of Mo arrays. However, when operated in the presence of O-2, Ir field emitter arrays proved to be more robust and showed improved emission current stability versus their Mo counterparts. (C) 2000 American Institute of Physics. [S0003-6951(00)03946-2].