Residual gas effects on the emission characteristics of silicon field emitter arrays

Measurements have been performed on the degradation of emission from silico n field emitting devices in ultrahigh vacuum (UHV) and vacuums containing C O2 and CH4 with anode potentials of 0 and 2500 V. Degradation is very fast in CO2, slower in CH4, and very slow in UHV. Analysis of the data using a n umerical simulation shows that, in UHV, the degradation can be explained by an increase in work function with time. For CO2 and CH4, however, it is pr imarily due to a blunting of the tips that is partly compensated for by a d ecrease in work function as emission progresses. There is some evidence for tip sputtering being important in the case of CO2 at high anode voltages. (C) 2000 American Vacuum Society. [S0734-211X(00)06302-2].