Fabrication of diamond-like amorphous carbon cantilever resonators

Amorphous carbon (a-C) films were deposited by an off-plane double bend filtered cathodic vacuum arc technique fitted with a plasma immersion ion implantation system. High resolution XPS measurements showed these films have an sp3 content of about 60%. Laser-surface acoustic wave measurements have shown such films to have a Young’s modulus and density of 310GPa and 2.33g∕cm3. 1.2μm thick a-C films were grown and subsequently patterned into 150μm×50μm cantilevers using standard photolithography. Residual stress measurements were obtained from the curvature of bend of the cantilever. An accurate knowledge of the microstructural properties will in turn give accurate modeling results. Simulation results showed that such free-standing cantilevers fabricated with amorphous carbon films have resonant frequency much higher than standard polysilicon cantilevers. As such, free-standing diamond-like amorphous carbon cantilevers had been fabricated. The resonant frequency of these cantilevers was measured by laser vibrometer to be ∼108MHz, in very good agreement with simulation results.