Tensile properities of single-crystal-silicon fully coated with submicrometer-thick PECVD DLC

The paper reports the improvement of tensile strength of single-crystal silicon (SCS) microstructures fully coated with sub-micrometer thick diamond like carbon (DLC) film using plasma enhanced chemical vapor deposition (PECVD). To minimize the deformations or damages caused by non-uniform coating of DLC, which has high residual stress, the released SCS specimens with the dimensions of 120 μm long, 4 μm wide and 5 μm thick were coated from the top and bottom side simultaneously. Three kinds of different deposition bias voltages were adopted with the thickness around 150 nm. The tensile strength improved up to 53.5% by the full coatings depending on deposition bias voltage. In addition, the deviation in strength reduced significantly compared to bare SCS specimen.