Fabrication Of Smooth Diamond-Like Carbon Microcantilever Arrays

The amorphous carbon films prepared by filtered cathodic vacuum arc (FCVA) deposition system are superior in nature with very smooth surface morphology, relatively high hardness, favorable tribological behaviour and excellent bio-compatibility. These exceptional qualities make them suitable for many device applications. However, the superior quality films prepared at relatively lower substrate bias such as -80V exhibits high compressive stress and thus limit the thickness of the film. This constraint is overcome by stress reduction, which is achieved by preparing the film in conjunction with high substrate pulse biasing. Free-standing Diamond-like Carbon (DLC) micro-cantiliver arrays were successfully fabricated by a single photolithography step. The relatively thick (~1μm), smooth (Rms ~0.75nm), low stress ( substrates, by the FCVA deposition system in conjunction with high substrate pulse biasing of -5kV, 900Hz and 30μs. The undecutting of the microstructure was carried out by anisotropic wet etching of Si in 40 wrt% KOH at 23°C for 31 hrs. The SEM image of the free-standing DLC micro-cantiliver arrays reveals that the maximum transverse deflection of the cantilever at the free end is quite low. The quantitative measurements of deflections were also carried out using an optical profiler to verify.