To tackle the issue, researchers at the University of Alberta, Canada, and NINT NRC, US, have designed a thin-film copper-hafnium alloy with attributes optimized for AFM-probe applications. Films are deposited using co-sputtering and subsequently patterned into AFM probes using optical lithography.

A unique combination of mechanical, surface and electrical properties, owing to the glassy microstructure of the alloy, allows for the microfabrication of conductive and optically reflective AFM probes of arbitrary sizes and geometries. The realized devices have a 10 nm tip radius, which is competitive with silicon and SiN-based conventional AFM cantilevers.

In the past, fabrication of all-metal cantilevers has proved practically impossible due to cantilever curling caused by differential stresses developed during polycrystalline grain growth. This critical problem is circumvented in this design because the optimized copper-hafnium glassy films possess minimal stress gradients.

Successful imaging using these next-generation AFM probes was performed, demonstrating the feasibility of all-metal AFM probes and their potential for advancing the capabilities of numerous AFM technologies.

The researchers presented their work in Nanotechnology.