Individually Addressable Fully Integrated Field Emission Electron Source Fabricated by Laser Micromachining of Silicon

A cathode with individually addressable Si tips allows the observation of the activation procedure and emission behaviour of each field emission emitter at any time of the measurement. The cathode consists of an array of $2\mathrm{x}2$ conically shaped emitter structures, which were fabricated by laser micromachining and wet etching of a Si substrate bonded on a glass carrier. Using the same process, a Si extractions grid was fabricated and mounted onto the emitter. Integral field emission measurements were performed in a diode configuration in a vacuum chamber at pressures of about 10–9 mbar. The emitters show an onset voltage between 200 V and 300 V. The emission current for each emitter on the cathode was regulated to a given value (1.0 $\mu\mathrm{A}, 2.5\mu\mathrm{A}, 5.0\mu \mathrm{A})$ by an external regulating circuit and was recorded individually during the measurement. With such approach, the relation between the emission behaviour and the geometry of emitters can be studied in detail. In addition, the current stabilization of each emitters of an array can be investigated, which led to a current stability of better than 0.5%.