Single Wafer Surface Micromachined Field Emission Electron Source

This paper reports on the design, fabrication and characterization of a MEMS electron source for low voltage electron emission (10 μA below 100 V) entirely built within a single silicon wafer. This device consists of a hermetically sealed microcavity that encapsulates an array of field emission silicon tips and a reaction chamber to which the emitted electrons are accelerated. An electron transparent membrane (20 nm-thick SiN) is positioned in between the two cavities. SiN circular pillars are designed to support the microcavities, control the tip-to-membrane distance and isolate the electrodes. The device is fabricated using a surface micromachining process that reduces the distance between the emitters and the electrodes leading to low voltage field emission.