INFRARED STUDIES OF HARD HYDROGENATED AMORPHOUS-CARBON (A-C-H) FILM AND THE EFFECT OF ARGON PLASMA TREATMENT

The hard hydrogenated amorphous carbon (a-C:H) films were deposited on both sides of well polished germanium (Ge) substrate by RF plasma dec omposition of benzene vapours. Infrared spectroscopy was used to measu re the transmission and Sp3/Sp2 ratio of diamond-like carbon (DLC) fil m as a function of plasma treatments. It has been demonstrated that th e partial etching of a-C:H film by argon plasma treatment may be a sui table process (1) to improve the film quality and also (2) to tailor a t required wavelengths the infrared transmission of a-C:H coated Ge op tics.