Effect of the Soft X-rays on Highly Hydrogenated Diamond-Like Carbon Films

The effect of soft X-ray irradiation of diamond-like carbon films in vacuum was investigated using synchrotron radiation (SR). Etching and the desorption of hydrogen upon SR exposure in vacuum occurred in highly hydrogenated diamond-like carbon (H-DLC) films; these processes were not observed in the irradiation of a low-hydrogenated DLC film. The extent of decrease in hydrogen content due to SR exposure was found to decrease with increasing the etching ratio of the H-DLC film. This indicates that hydrogen desorption from the H-DLC films competed with the etching process. Namely, the modified surface, in which hydrogen content was decreased by SR exposure, was immediately removed from the H-DLC film that had a high etching rate. (C) 2011 The Japan Society of Applied Physics