Current–voltage characterization and temporal stability of the emission current of silicon tip arrays

Abstract

We report an investigation of current–voltage ( I– V) characteristics of silicon tip arrays, presenting a discussion of the electrical phenomena with respect to the field emission current. The samples were fabricated on silicon substrates using reactive ion etching SF 6 plasma and sharpened by thermal oxidation. Current–voltage measurements were performed using anode–cathode distances of 30 and 50 μm, and followed a Fowler–Nordheim behavior. No significant changes in the field enhancement factor were found for the different anode–cathode spacings. However, a rise in threshold voltage was detected as anode–cathode separation increased. We also studied the histeresis behavior of the silicon tips for a fixed distance and found differences in the threshold voltage for ascending and descending ramps, possibly caused by a variation in the “effective” work function. Finally, we investigated the short-term current emission stability and found the behavior to be consistent with evidence from the literature, which correlates the instability in electron emission to localized interface traps and gas desorption events.