Tough New Probe Developed

Diamond is probably the optimal tip material for many applications. Until now, commercially available diamond AFM tips are either glued to a microcantilever or made by coating a silicon tip manufactured using conventional microfabrication techniques. Chemical vapor deposition (CVD) techniques for growing thin films of synthetic diamond typically do not produce single-crystal films, in which atoms are all oriented in a regular lattice.

The material UNCD is the closest diamond atomic structure in which the material is organized in very small grains leading to smooth surfaces easy to mold and shape by microfabrication techniques. The similarity of UNCD to single-crystal diamond and its superiority to silicon, silicon carbide and other micro- and nanoelectromechanical systems (MEMS and NEMS) materials, in the context of strength, toughness and wear performance, has been established.

The standard MEMS microfabrication techniques used for the diamond tips - an important feature of this development - provides scalability to massively parallel arrays of probes for high throughput.

"This technology offers tremendous potential for the large-scale production of single- and two-dimensional tip arrays of doped and undoped diamond exhibiting superior wear resistance and functionality," said team leader, Horacio D. Espinosa, professor of mechanical engineering at Northwestern's McCormick School of Engineering and Applied Science. "The approach can be easily integrated with the AFM Nanofountain Probe (NFP) recently developed by our group and, in this way, achieve the merging of two unique technologies.

"The demonstrated low wear and writing capability of UNCD tips with chemical inks is very promising. Moreover, the possibility of doping the material to make it conductive is very exciting and opens a large number of opportunities for scientific discovery."; Source: Northwestern University