Two-step controllable electrochemical etching of tungsten scanning probe microscopy tips
- Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia)
Dynamic electrochemical etching technique is optimized to produce tungsten tips with controllable shape and radius of curvature of less than 10 nm. Nascent features such as 'dynamic electrochemical etching' and reverse biasing after 'drop-off' are utilized, and 'two-step dynamic electrochemical etching' is introduced to produce extremely sharp tips with controllable aspect ratio. Electronic current shut-off time for conventional dc 'drop-off' technique is reduced to {approx}36 ns using high speed analog electronics. Undesirable variability in tip shape, which is innate to static dc electrochemical etching, is mitigated with novel 'dynamic electrochemical etching.' Overall, we present a facile and robust approach, whereby using a novel etchant level adjustment mechanism, 30 Degree-Sign variability in cone angle and 1.5 mm controllability in cone length were achieved, while routinely producing ultra-sharp probes.
- OSTI ID:
- 22093632
- Journal Information:
- Review of Scientific Instruments, Vol. 83, Issue 6; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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