Hyperthermal Atomic Oxygen Beam Irradiation Effect on the Hydrogenated Si-doped DLC Film

抄録

We investigated the effect of hyperthermal atomic oxygen beam irradiation on hydrogenated Si-doped Diamond-Like Carbon (hydrogenated Si-DLC) films for the purpose of use as a solid lubrication material in space. We found that film thickness of hydrogenated Si-DLC was constant after the exposure to atomic oxygen beam. From this result, the hydrogenated Si-DLC films have resistance to etching by the irradiation of atomic oxygen, unlike hydrogenated non-dope DLC films. In addition bulk composition of hydrogenated Si-DLC film kept constant. Especially, hydrogen content in Si-DLC film did not decrease. Therefore, hydrogenated Si-DLC film is expected to keep low fiction properties in a vacuum. Furthermore, the atomic oxygen beam fluence dependence of X-ray Photoelectron Spectroscopy (XPS) and Near Edge X-Ray Absorption Fine Structure (NEXAFS) spectra of hydrogenated Si-DLC films were measured. From these studies, it was found that the C atoms on the hydrogenated Si-DLC surface were desorbed, but Si atoms were remained on the hydrogenated Si-DLC surface as the SiO_x by the collision of atomic oxygen. This SiO_x layer was considerable to disturb the erosion of bulk film against atomic oxygen. From the element distribution in depth direction, it was found that the thickness of SiO_x was about 5 nm.