Magnetically enhanced plasma coating of nanostructures with ultrathin diamond-like carbon films

Diamond-like carbon (DLC) films are widely used as protective coatings
in a variety of technicalmacro- and micro-applications. However,
most of the widely-used coating methods are not suitable for nanoscale
applications. In this work, the method of magnetically enhanced
plasma deposition (MEPCVD) was employed for the coating of AFM
probes and free-standing nanostructures with 3–20 nm thick DLC
films. The carbon bonding structure, mechanical and tribological
properties of the films as well as the anisotropy of the coatings and its
effect on the shape of nanoscale features were investigated and it is
shown that the method employed produces very smooth coatings
(roughness below 0.2 nm) with a significantly lower than usual internal
stress of 0.5–0.8 GPa. Wear tests of AFM probes at a high load (1 mN)
showed that the DLC coating decreases their wear rate by two orders
of magnitude. It was found that coating of free-standing nanostructures
even with ultrathin DLC films may cause their deformation
due to the interface stress when the coating is asymmetric.