Study on the change of structure and optical properties of DLC thin films by mixed gas method

DLC (diamond-like carbon) films have excellent optical properties, especially in the mid-infrared band (8-14 micron). Because of the adjustable refractive index in a certain range, it can be matched with more infrared materials, which is a hot research topic in infrared optics. In this paper, the effects of technological parameters and mixed gases (H2 and Ar) on the structure and properties of DLC films were studied. The results show that the process parameters can change the structure of the film, so that some properties of the film can be changed accordingly, but DLC films with high thermal stability and low internal stress can not be obtained simultaneously. When other gases are mixed in the reaction source gas, the structure and properties of the film will change, which is mainly due to the different role of the introduced gas in the film deposition process.