Atomic-level flat polishing of polycrystalline diamond by combining plasma modification and chemical mechanical polishing

This paper presents an atomic-level flat polishing method based on hydroxyl (•OH) oxidation combining plasma modification and chemical mechanical polishing (CMP) of polycrystalline diamond (PCD). The PCD surface was firstly modified using •OH generated by He-based H₂O₂ plasma leading to the formation of an approximately 30 nm thick uniform oxidation layer on the PCD surface composed of carbon-oxygen mixed layer and oxygen-rich layer. Reactive force field molecular dynamics (ReaxFF MD) simulations explained the plasma modification mechanism. The modified layer was then removed using CMP resulting in an atomic-level flat surface with arithmetical mean height (Sa) of 0.366 nm.