Khan Yasser, Al-Falih Hisham, Zhang Yaping, Ng Tien Khee, Ooi Boon S
Photonics Laboratory, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
Rev Sci Instrum. 2012 Jun;83(6):063708. doi: 10.1063/1.4730045.
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.
动态电化学蚀刻技术经过优化，可生产出形状可控、曲率半径小于10纳米的钨尖。利用了诸如“动态电化学蚀刻”和“脱落”后的反向偏置等新特性，并引入“两步动态电化学蚀刻”来生产具有可控纵横比的极尖锐尖端。使用高速模拟电子器件，传统直流“脱落”技术的电子电流切断时间缩短至约36纳秒。新型“动态电化学蚀刻”减轻了静态直流电化学蚀刻固有的尖端形状不良变异性。总体而言，我们提出了一种简便且稳健的方法，通过使用新型蚀刻剂液位调节机制，实现了锥角30°的变异性和锥长1.5毫米的可控性，同时常规生产超尖锐探针。
