The polishing surface quality of single crystal diamond with GO green-enhanced diamond hybrid slurry and material removal mechanism analysis

Single crystal diamonds, which have extremely high hardness and brittleness, can provide lower power consumption and higher frequencies for electronic devices compared with other semiconductor materials. The chemical mechanical polishing method is usually used to realize the flattening of single crystal diamond workpiece. However, the conventional oxidants may cause damage to polishing tools and experimental equipment, and even lead to environmental pollution. Therefore, a graphene oxide green-enhanced diamond hybrid slurry was introduced in this study for single crystal diamond polishing with quartz glass as a polishing disk. The effect of graphene oxide on polishing surface quality was analyzed, and the polishing experiments were carried out with different polishing pressures and durations to investigate the influence of varying process parameters. The molecular dynamics method was used to simulate the formation and removal process of graphene oxide-induced degraded layer on single crystal diamond surface. The scratched morphologies on single crystal diamond surfaces were obtained, and the amorphization degree was analyzed to reveal the subsurface damage mechanism. The simulation shows that the oxygen-containing functional groups from graphene oxide chemically react with the carbon atoms on the single crystal diamond surface, removing in the form of CO, CO₂, or adhering to the abrasive grains. Also, the chemical adsorption reduced the activation energy of carbon atoms in single crystal diamond, and made it more loosely arranged and easier to be removed by mechanical scratching, which explained the experimental results.