Electrically conducting probes with full tungsten cantilever and tip for scanning probe applications

We have developed a new hybrid AFM probe combining an SU-8 polymer body with a full tungsten cantilever having a nanometric tip. The fabrication is based on surface micromachining a silicon wafer, where tungsten is sputter deposited in oxidation sharpened moulds to yield sharp tips with radius below 20 nm. The material properties of tungsten were measured, yielding a hardness of 14 GPa, a specific resistivity of 14.8 μohm cm and Young’s modulus of 380 GPa. Analyses of the probes show a mechanical quality factor of 90 in air, and a low contact resistance of 25 ohm on a gold sample is measured. AFM imaging is demonstrated. As a step in the development of a robust electrically conducting AFM probe, the results are very promising.