Towards diamond micro four-point probes

Diamond has extreme physical properties, and it is used for critical applications in micro- and nanotechnology and nanosciences. Micro four-point probes for electrical characterization of metal and semiconductor thin-films are made from metal coated silicon microcantilevers. The limiting factors in probe lifetime are frictional wear and thermal damage from electrical overstress.

Diamond has superior thermal conductivity and wear resistant properties which could improve probe lifetime. In this paper, we present wafer-level fabrication of polycrystalline diamond micro cantilevers for micro four-point probe applications. The process only requires two photolithography steps. We show great design flexibility and demonstrate extremely mechanical robust freestanding diamond cantilever up to 300 μm long.

We believe that this process may find important applications beyond micro four-point probes. The next step is to implement micro four-point probes using high quality electrically conductive diamond when it becomes available.