Abstract
This research focuses on revealing mechanical properties of diamond-like carbon (DLC) films for surface modification in MEMS. New compact tensile tester operating in an atomic force microscope (AFM) was developed for characterization of Young's modulus, Poisson's ratio and fracture strength of DLC films. The DLC films having sub-micron thickness from 0.2μm to 0.5μm were deposited onto microscale single crystal silicon (SCS) specimens by PE-CVD method of the hot cathode PIG discharge type. Young's moduli of the DLC films in AFM tensile tests ranged from 99 GPa to 112 GPa. AFM tensile tests and nano-indentation tests revealed that Poisson's ratio of DLC films ranged from 0.27 to 0.40. Fracture stress of the films also exhibited from 0.5 GPa to 1.1 GPa, which depended on the film thickness and deposition condition. SEM observations of fracture surfaces suggested that the fracture initiation of DLC/SCS specimens was induced at the boundary between the film and SCS substrate.
