The investigation of thermal effect on the properties of pulsed laser deposited diamond-like carbon films

The properties of diamond-like carbon (DLC) film were revealed to mainly depend on the ratio of sp³/sp² carbon bonds. In order to investigate the factors that influence the change of sp³/sp² ratio, the deposition on a substrate under heating and post-annealing treatments of DLC films has been carried out. Comparing the results from substrate heating with post-annealing treatments, it was confirmed that there is a thermal effect caused by excess thermal energy. DLC films were deposited using a pulsed laser deposition (PLD) technique on Si(100) substrates and the temperature range of substrate heating and post-annealing was varied between 25 and 500°C. The properties of DLC films according to the temperatures were analyzed by various techniques. X-ray diffractometer and Raman spectroscopy were used to evaluate the structure of DLC films and investigate the microstructural change with temperature. Rutherford backscattering spectrometry and scanning electron microscopy were used to obtain the information about the density of DLC films. The results of photoluminescence and four-point probe agreed well with the above analyses.