High current density Si field emission devices with plasma passivation andHfC coating

A novel self-aligned process was developed to fabricate gated Si field emis sion devices. At a gate voltage of 100 V, the emission cut-rent from an arr ay of 100 tips increased from 284 to 460 mu A and the turn-on voltage decre ased from 31 to 21 V after H-2 plasma passivation using an inductively coup led plasma (ICP) source for 2 min. The improvements correspond to a 1,28-eV reduction in the effective work function of the emitters and the instabili ty of the emission current decreased from 11.25 to +/-0.25% after H-2 plasm a passivation. Emitter tips were also coated with Mo silicide and HfC. The emission current increased from 230 mu A for uncoated emitters to 268 mu A for emitters coated with Mo silicide and 389 mu A for emitters coated with HfC, The turn-on voltage decreased from 50 to 41 and 25 V while the breakdo wn voltage increased from 126 to 129 and 143 V when Mo silicide and HfC wer e used for coating, respectively, which correspond to reductions of 0.95 an d 2.23 eV, respectively, in the effective work function of the emitters. Si ngle emitter tips have similar emission characteristics as high-density hel d emitter arrays? indicating excellent emission uniformity from the arrays.