Growth of diamond thin films on nickel-base alloys

Abstract

Microwave plasma-assisted chemical vapor deposition has been employed to grow diamond films (thickness up to 50 μm) using a gas mixture of hydrogen (H 2), methane (CH 4), and oxygen (O 2) on various substrates such as Ni 200, MONEL 400, INCONEL 600, INVAR, single crystal nickel with orientations of (100), (111), etc. Nucleation of diamond on the substrates has been achieved by seeding with diamond particles, manual scratching, and ultrasonic agitation in methanol (CH 3OH) containing diamond particles. The substrate underwent H 2 microwave plasma treatment for 5–60 min to remove any oxide film present prior to diamond growth. Growth of diamond over MONEL 400 was achieved at various CH 4 concentrations in H 2. As-deposited films were analyzed by scanning electron microscopy (SEM), Raman spectroscopy, secondary ion mass spectroscopy, X-ray photoelectron spectroscopy and Auger electron spectroscopy. According to SEM the morphology of the grown films was (100) texture over the entire surface (<0.5 cm 2) of Ni 200 substrate. Raman analysis of the top side of deposited film confirms for diamond and on the back side of the free-standing film shows the characteristic peaks for diamond and graphite. As-deposited films were diamond and other forms of non-diamond carbon on INCONEL 600 and INVAR.