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Fabrication and characterization of a focused ion beam milled lanthanum hexaboride based cold field electron emitter source Featured

authors
G. Singh, R. Bücker, G. Kassier, M. Barthelmess, F. Zheng, V. Migunov, M. Kruth, R. E. Dunin-Borkowski, S. T. Purcell, and R. J. D. Miller
date published
Aug. 27, 2018
journal
Applied Physics Letters
volume, number
113 (9)
pages
093101
doi
https://doi.org/10.1063/1.5039441
abstract

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.