Cleaning diamond surfaces via oxygen plasma inhibits the formation of a TiC interface

TiC at the diamond‑titanium interface is known to be a stable and beneficial layer for diamond based electronic devices. However, certain cleaning steps can alter the chemical composition of this interface. One such process is oxygen plasma etching, which terminates the surface of the diamond with oxygen. Oxygen is highly reactive with titanium, forming titanium oxides. Theoretically the titanium-diamond interface can be improved through sufficient annealing after device fabrication. To test this, we investigated the interface of oxygen-terminated polycrystalline B-doped diamond and titanium via XPS in an effort to determine if oxygen would rearrange away from the diamond surface and TiC would be formed through post-deposition annealing. After annealing at temperatures up to 900 °C, it was found that TiC was not detected at any point in this experiment. Oxygen-termination, despite its de-scumming capabilities, likely inhibits the formation of TiC at the diamond surface.