We report on a method of fabricating lanthanum hexaboride (LaB6) cold field emission tips with sub-100-nm apices by using a combination of electrochemical etching and focused ion beam milling. The primary advantage of combining the two methods is rapid fabrication while maintaining reproducibility. The LaB6 tips have low work functions and high mechanical stabilities and are chemically inert to residual gases. Field emission characterization was performed on three tips, with apex sizes of 15, 85, and 80 nm yielding 10 nA cold field emission currents at 0.76, 3.9, and 3.6 kV extraction potentials, respectively. All three tips showed excellent emission current stability for periods exceeding 30 min in a 5 × 10−9 mbar vacuum.

We present our work on the development and characterization of a practical and robust LaB <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf> based cold field emitter electron source. To this end we prepared a Tantalum mounted single crystal LaB <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf> rod that was chemically etched, yielding an apex size of 2μm. The obtained tip is loaded into a ultra high vacuum chamber for pulsed emission in the μs regime, using extraction voltage pulsing. Further processing using focused ion beam (FIB) milling, and conditioning using a build-up technique will be used to reduce the apex size to the nm range.