Pure and silicon (Si)-incorporated diamond-like carbon (Si-DLC) thin films were deposited onto Si wafers using a reactive sputtering method. By varying the SiH4 flow rate, DLC films of various Si contents were achieved. The effects of Si incorporation on the thermal stability and tribological properties of the DLC films were studied with reference to the modifications to their chemical bonding at elevated temperatures along with their friction mechanisms. Fourier transform infrared spectroscopy (FTIR), optical microscopy, field emission scanning electron microscopy (FESEM) with energy-dispersive X-ray spectroscopy (EDS), and micro-Raman spectroscopy were applied to determine the film's thermal, friction, and wear behaviors. As the Si was incorporated, the Si-O bond intensity increased and the Si-C bond remained within the films, which presumably resulted in the good thermal stability. It was found that the lower friction coefficient of the Si-incorporated films is correlated to the formation of a SiO2 transfer film on the surface of the wear scar.

Keywords: DLC; Reactive sputtering; Si incorporation; Thermal stability; Friction and wear