Nucleation and growth of oriented diamond films on nickel substrates
(100) and (111) oriented diamond films were grown on similarly oriented single crystal Ni substrates using a multi-step seeding and growth process. In-situ reflection monitoring revealed large surface reflectivity changes upon heating of the seeded substrate in H2. The reflectivity change was attributed to the surface melting and dissolution of the seeding particles. The presence of atomic hydrogen lowered the eutectic melting point of the Ni-C compound from 1325 °C to about 1100 °C. It appeared that the molten Ni-C-H surface layer suppressed graphite formation, which is normally observed in diamond growth on Ni, and promoted diamond nucleation. The oriented diamond films were also obtained using non-diamond carbon seeding. Based on experimental observation, a proposed model is described to explain the nucleation mechanism from the molten Ni-C-H surface layer.
