948708.fig.003a
(a) Photolithography
948708.fig.003b
(b) SiO2-RIE-etching
948708.fig.003c
(c) Si-RIE-etching
948708.fig.003d
(d) Si-tip-emitter
Figure 3: SEM images of the structured cathode fabrication process. (a) Developed photoresist. (b) Patterned SiO2 disks. (c) Etched bulk Si. (d) Final emitter.