Boron-doped diamond scanning probe for thermo-mechanical nanolithography

The good thermal conductivity, wear resistance and chemical inertness of a probe material are the essential terms for the processing speed and durability in the probe-based thermo-mechanical lithography. Considering these criteria, diamond can be regarded as the ideal material for a probe. This paper describes the microfabrication, evaluation and application of a boron-doped diamond micro-probe with an integrated resistive heater element. The diamond heater with a pyramidal tip, which is formed at the end of two diamond beams, can be electrically heated by flowing a DC or AC current. The high thermal conductivity of the diamond base supporting the heater element allows a very quick thermal response of 0.45 μs. A hard-wearing sharp diamond tip formed by silicon-lost mold technique shows an excellent durability in contact operation with a sample. Demonstration of thermo-mechanical nanolithography with this heated probe exhibits line patterns with the feature size of 40 nm on a Polymethylmethacrylate (PMMA) film and transferred pits-pattern with the diameter of 230 nm and the pitch of 400 nm onto the silicon substrate.