Ultra sharp crystalline silicon tip array used as field emitter

This article describes the fabrication of single crystal silicon field emission tip arrays. Each array consists of 2500 tips. We used 4 in. (100) oriented n type silicon wafers 0.008 – 0.020 Ωcm, Sb doped. The tips were formed using a RIE process. We achieved crystalline emitter tip radiuses of 1.5 – 2 nm. The extraction grid is a self aligned, sputter deposited Ti_0.1W_0.9 film. The radiuses of the extraction grid apertures range from 300 to 150 nm and have a tip to tip spacing from 10 to 5 μm. The testing was done in vacuum with a distance of 500 μm between extraction grid and anode. We have seen maximum stable array currents up to 2 μA. An anode current of 10 nA was initially detected at a minimal gate bias of about 14 V.