Nanometre scale mechanical properties of extremely thin diamond-like carbon films

Abstract

Extremely thin diamond-like carbon (DLC) films are deposited by the filtered cathodic vacuum arc (FCVA) and plasma chemical vapour deposition (p-CVD) methods. The target thicknesses of the extremely thin protective DLC films deposited on a Si (100) surface by FCVA and p-CVD are 0·1, 0·4, 0·8, 1·0, 2·0, 5·0 and 100·0 nm. Nanoindentation hardness and nanowear resistance are evaluated by atomic force microscopy (AFM). The nanoindentation hardnesses of 100 nm thick DLC films deposited by FCVA and p-CVD are 57 and 25 GPa respectively. The nanowear test by AFM clarifies the mechanical properties of extremely thin DLC films. The wear depths of 1 and 2 nm thick FCVA-DLC films are extremely shallow. The wear depths of the 1·0 and 2·0 nm thick p-CVD-DLC films exceed the film thicknesses after five sliding cycles. These results reveal differences in the wear resistance of extremely thin DLC films and the superior mechanical properties of FCVA-DLC thin films.