Diamond Growth on Haynes 214 Alloy

Abstract

A major target in diamond deposition is the growth of heteroepitaxial diamond films that are free from impurities, grain boundaries and defects for use in electronic applications. Nickel has been identified as a material with a close lattice match to diamond that minimises defect formation in diamond films but as a substrate, nickels' higher thermal expansion coefficient with respect to diamond, and the interfacial formation of amorphous and graphitic carbon before nucleation of diamond, leads to a weakened diamond/metal bond. Haynes 214 alloy is a nickel-based alloy used in high-temperature environments. Regions within this alloy contain amounts of aluminium known to affect the ability of nickel to stabilise amolphous carbon and graphite. Areas rich in aluminium discourage the formation of sp2 carbon, creating a barrier to carbon diffusion and allowing diamond nucleation to occur on the metal surface. Diamond deposition on Haynes 214 alloy using combustion assisted chemical vapour deposition (CACVD) rapidly produced a well structured, polycrystalline diamond film that typically delaminated with sample cooling. The film exhibited areas that were transparent corresponding to areas on the substrate rich in aluminium and dark areas matching nickel rich areas of the substrate surface catalysing the formation of amorphous and graphitic carbon.