Fabrication and Simulation of Amorphous Carbon Cantilever Structures

In view of the superior bio-compatibility of amorphous carbon (a-C) films, a study has been carried out on the fabrication and simulation of free-standing amorphous carbon micro-cantilevers. The fabrication of micro-structure was carried out by a single photolithography step. A 1.7micro-meter thick, low stress, smooth (R_rms ∼0.75nm) a-C films were deposited by filtered cathodic vacuum arc deposition (FCVA) system, in conjunction with high substrate pulse biasing on patterned n-doped Si <100> substrates. Subsequently, the photoresist was lifted-off in acetone and which is followed by undercutting of the cantilever structures in 40% KOH solution. The deflection of the free-standing cantilever structures was measured using an optical profiler, and the stress in the a-C cantilever structures was independently calculated from the deflection of the cantilever beam and the total tilt angle. This stress value is compared with the stress in the film measured from the film-substrate sandwich by radius of curvature technique. Simulation of the cantilever assembly was carried out to obtain the deflection and stress distribution. The simulated parameters are compared with the experimental results.