Micro-Tribological Properties of Extremely Thin Diamond-Like Carbon (DLC) Films

Micro-tribological properties such as nanowear resistance and low load reciprocating friction of extremely thin DLC (Diamond-like carbon) films deposited by bend type FCVA (Filtered cathodic vacuum arc) and ECR (Electron cyclotron resonance)-CVD (Chemical vapor deposition) techniques were evaluated. Structure and composition of these DLC films were evaluated using Raman spectroscopy, TEM (Transmission electron microscopy) and AES (Auger electron spectroscopy). These analyses show that FCVA-DLC film has the tetrahedral structure. Nanowear properties were evaluated by AFM (Atomic force microscopy). FCVA-DLC film shows superior nanowear resistance. Wear depths of 1- and 2-mn-thick FCVA-DLC films are extremely shallow as less than 1 nm. However, wear depths of ECR-CVD-DLC are deeper and reach to its thickness after. few slidings. From the 10 mN-load reciprocating friction test, friction coefficients of nm-thick ECR-CVD-DLC films are fluctuated, and their damages are greater than those of FCVA-DLC films. From the friction properties dependence on film thickness, friction coefficient of FCVA is low and stable. In contrast, the friction coefficients of ECR-CVD-DLC films with thinner than 1.0 nm are as high as that of Si(100) substrates. These results reveal the excellent wear resistance of extremely thin films deposited by FCVA.