Friction force microscopy study of annealed diamond-like carbon film

In this paper we introduce mechanical and structural characteristics of diamond-like carbon (DLC) films which were prepared on silicon substrates by radio frequency (RF) plasma enhanced chemical vapor deposition (PECVD) method using methane (CH4) and hydrogen (H-2) gas. The films were annealed at various temperatures ranging from 300 to 900 degrees C in steps of 200 degrees C using rapid thermal processor (RIP) in nitrogen ambient. Tribological properties of the DLC films were investigated by atomic force microscopy (AFM) in friction force microscopy (FFM) mode. The structural properties of the films were obtained by high resolution transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The wettability of the films was obtained using contact angle measurement. XPS analysis showed that the sp(3) content is decreased from 75.2% to 24.1% while the sp(2) content is increased from 24.8% to 75.9% when the temperature is changed from 300 to 900 degrees C. The contact angles of DLC films were higher than 70 degrees. The FFM measurement results show that the highest friction coefficient value was achieved at 900 degrees C annealing temperature. (C) 2012 Elsevier Ltd. All rights reserved.