Two-step controllable electrochemical etching of tungsten scanning probe microscopy tips
Abstract
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 ∼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° variability in cone angle and 1.5 mm controllability in cone length were achieved, while routinely producing ultra-sharp probes.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 01, 2012
- Source ID
- 10.1063/1.4730045
Entities
People
- Boon S Ooi
- Hisham Al-falih
- Tien Khee Ng
- Yaping Zhang
- Yasser Khan
Organizations
- Defense Advanced Research Projects Agency
- King Abdullah University of Science and Technology