DLC FILM PREPARATION BY LASER-ARC AND PROPERTIES STUDY

The LASER-ARC was used to prepare diamond-like carbon (DLC) films up to a thickness of about 1 μm on different substrate materials. The laser-induced, laser-pulsed and laser-guided vacuum are evaporation is a precisely controlled pulsed plasma source for which the film deposition is characterized by plasma sustained ion bombardment. At a deposition rate of 1 nm/s DLC films were prepared on Si(111)-wafers, quartz, glass, ZnSe and NaCl or KCl substrates with an increased adhesion allowing wear tests. Mechanical, optical and electrical properties of the films were studied depending on the substrate deposition temperature (500 °C > T > 25 °C) and on substrate bombardment with Ar+ ions. Film-substrate interfaces were analyzed by secondary ion mass spectrometry. Unlubricated friction measurements in air were carried out with a ball-on-disk machine using hardened steel and Al2O3 balls. The friction coefficient varied depending on deposition conditions from 0.1 to 0.5. The optical properties of the films were estimated both by ellipsometry (λ = 633 nm) and spectral reflection and transmission measurements. The refractive index varied between 2.3 and 1.8 with an extinction coefficient from 0.2 to 1.1, corresponding to substrate deposition temperature of 25 °C to 500 °C. The optical band gap (Tauc-gap) was of the order of 1.3 eV at 25 °C and 0.3 eV at 500 °C. © 1992.