Etching voltage control technique for electrochemical fabrication of scanning probe microscope tips

A computer-controlled electrochemical etching system has been developed to fabricate sharp tips for scanning probe microscopy (SPM). In the system developed, an etching voltage control technique has been proposed. The proposed technique comprises two steps in a continuous electrochemical etching process: in the first step, a high etching voltage is applied to produce a tip having a low tip aspect ratio and in the second step, a low etching voltage is applied to prevent buildup of an oxide layer. Scanning electron microscope images of the SPM tips confirmed that the tips with a low aspect ratio and an almost oxide-free surface were successfully fabricated by the system developed.