Surface defects induced by in-situ annealing of hydrogenated polycrystalline diamond studied by high resolution electron energy loss spectroscopy

Plasma hydrogenation of polycrystalline diamond films results in a fully hydrogenated well-ordered diamond surface and etching of the amorphous phase located at grain boundaries. Vacuum annealing to 1000 °C followed by in-situ hydrogenation by thermal activated hydrogen of the bared diamond surface results in the formation of sp3-CHx adsorbed groups located on the top surface. Annealing of the in-situ hydrogenated surface to 600 °C results in desorption of these species and partial reconstruction of the film surface. Some irreversible surface degradation was detected in the in-situ annealed and hydrogenated surface compared to the state of the surface obtained upon plasma hydrogenation.