Abstract
In order to find Si-DLC films with more thermal stability, we have evaluated five types Si-DLC films (0, 4, 11, 21 and 29 at% Si) with changing the mixture ratios of two precursor gases (tetramethylsilane and toluene). We examined the effect of Si content and heat treatment at 770 K for 1.8 ks in the Air on mechanical properties, such as hardness, internal stress, friction coefficient and wear resistance. With the increase of Si content, internal stress of the film decreased, and the films which have more than 21 at% Si content did not decrease the hardness by the thermal treatment. The films of 11-21 at% Si content showed the lowest friction coefficient and the 21 at% Si content film showed the highest wear resistance after the annealing. Silicon oxide was formed on the surface of DLC film after the annealing. In the higher Si content film, the oxide layer seems to act as diffusion barrier of oxygen and they might prevent the graphitization of the Si-DLC films. The 21 at% Si content film is the most thermally stable in the five.
