Abstract
Nanometer-scale mechanical properties of extremely thin DLC films deposited using filtered cathodic vacuum arc (FCVA) and electron cyclotron resonance plasma chemical vapor deposition (ECR-CVD) methods were evaluated. Auger electron spectroscopy (AES) revealed these DLC films' thickness and composition. Results showed that the obtained DLC films' thickness nearly corresponds to the set thickness. Nanoindentation hardness and nanowear resistance of the DLC films were investigated using atomic force microscopy (AFM). The nanoindentation hardness of 100-nm-thick DLC films deposited using FCVA and ECR-CVD were 57 GPa and 25 GPa, respectively, as evaluated at 40 μN load. The difference of nanoindentation curves of 5- and 2-nm-thick DLC films deposited using FCVA and ECR-CVD methods is only slightly detectable. It is difficult to evaluate the ultrathin DLC films' hardness using a nanoindentation test of several nanometers' thickness. In contrast, mechanical properties of the extremely thin DLC films can be clarified using nanowear testing with AFM. Wear depths of 100-, 5-, 2-nm-thick FCVA-DLC films are all less than 1 nm: extremely shallow. Especially, the wear depth of 100-nm-thick FCVA-DLC film is nearly 0.1 nm, even at 30 μN load. However, the wear depths of 100-, 5-, 2-nm-thick ECR-CVD-DLC films are greater than those of FCVA-DLC films. These results underscore the excellent wear resistance of extremely thin FCVA-DLC films.
