Emission statistics for Si and HfC/Si emitter arrays after gas exposure

Test arrays of gated Si emitters with N/sub tips/=100 tips have been fabricated. A HfC coating layer was deposited on the tips, showing effectiveness in lowering the operational voltage and improving the uniformity of the array emission. The Si and Si/HfC emitter arrays were measured in high vacuum conditions and after being subject to Ar and O/sub 2/ residual gases with partial pressures in the range 10/sup -4/ to 10/sup -6/ Pa, the evolution in time of the emission properties being recorded. The influence of residual gases on the field emission (FE) properties has been comparatively characterized through model parameter extraction.