Fabrication of Tungsten nanoprobes by Electrochemical etching: Role of cathode geometry and their use as electrical probe

TL;DR

This paper presents a low-cost method for fabricating tungsten nanoprobes using electrochemical etching, exploring how cathode shape influences probe geometry, and demonstrates their application in electrical measurements of microstructures.

Contribution

The study introduces a simple, inexpensive setup for fabricating tungsten nanoprobes and investigates the effect of cathode geometry on probe shape, enabling accessible nano-contact measurements.

Findings

Probe length varies from 0.58 mm to 2.15 mm.

Half cone angle ranges from 1.4° to 8.8°.

Probes exhibit low contact resistance (~4 ohms) and ohmic behavior.

Abstract

Electrical measurement of nano-scale devices and structures requires skills and hardware to make nano-contacts. Such measurements have been difficult for number of laboratories due to cost of probe station and nano-probes. In the present work, we have demonstrated possibility of assembling low cost probe station using USB microscope (US $ 30) coupled with in-house developed probe station. We have explored the effect of shape of etching electrodes on the geometry of the microprobes developed. The variation in the geometry of copper wire electrode is observed to affect the probe length (0.58 mm to 2.15 mm) and its half cone angle (1.4 to 8.8 degree). These developed probes were used to make contact on micro patterned metal films and was used for electrical measurement along with semiconductor parameter analyzer. These probes show low contact resistance ( 4 ohm) and follows ohmic behavior. Such probes can be used for laboratories involved in teaching and multidisciplinary research activities and Atomic Force Microscopy.