Silicon doped diamond-like carbon(Si-DLC) thin films with Si contents in the range 0-15 at.% were deposited on silicon substrates using a reactive sputtering method. The thermal annealing behavior of the films was investigated by annealing the films using a rapid thermal process(RTP) system. X-ray photoelectron spectroscopy(XPS), Raman spectroscopy, Fourier transform IR(FTIR) spectroscopy, high resolution transmission electron microscopy (HRTEM) and micro-hardness testing were used to determine the structural and mechanical property changes of the annealed pure and Si-DLC films. It was found that the graphitization process as a result of the D-band and G-band splitting, the increase of I-D/I-G ratio and G-peak position shifting started from 400 degrees C in the pure DLC films, and from 500 degrees C in the 15 at.% Si-DLC films, respectively. Moreover, in the case of the 15 at.% Si-DLC films the intensity of the Si-C bond was detected even after annealing at 600 degrees C, which indicated the formation of a SiC phase embedded in the amorphous carbon matrix. This formation of SiC nanocrystallies with a size of 5 nm was confirmed by HRTEM images, and then they were stable even after high temperature annealing although the size was decreased slightly. Therefore, the mechanical properties and thermal stability of the reactive sputtered Si-DLC films could be improved by the existence of SiC nanocrystallites after thermal annealing.

Keywords: Si-DLC thin flim; reactive sputtering; thermal annealing; nanocrystallite