A study of chemical products formed on sapphire (0001) during chemical–mechanical polishing

A study of chemical products formed on sapphire (0001) during chemical–mechanical polishing is presented. The results demonstrated that the formation and removal of chemical products both proceeded from the hexagonal close-packed sapphire Al-O layers described as atomic terraces, and the material removal rule of sapphire (0001) during chemical–mechanical polishing is the regular removal of chemical products formed from the atomic terraces, which were successfully characterized by AFM with super-sharp scanning probes. Besides, we also found that the surface with screw dislocations could not be polished completely by CMP due to the crystal distortion energy, and a hard polishing pad could remove scratches more effectively than a soft one •We obtain high-definition atomic terraces by AFM and super-sharp Si probe.•We demonstrate residual chemical products formed from atomic terraces during CMP and relative properties.•We infer the formation and removal rule of sapphire during CMP based on chemical products.•We demonstrate preferential removal rule caused by screw dislocations.