Comparison of surface and subsurface damage of mosaic single-crystal diamond substrate processed by mechanical and plasma-assisted polishing

Abstract The surface and subsurface damage of a mosaic single-crystal diamond (SCD) (100) substrate processed by mechanical polishing (MP) and plasma-assisted polishing (PAP) were studied. Scanning white-light interferometer (SWLI) (84-μm square) observation for different local positions showed that the surface damage such as scratches and deep pits were observed on the mosaic SCD substrate after MP, while such damage was completely removed after PAP. Scanning cathodoluminescence (CL) measurement of band-A emission for different local positions showed that scratches with high luminescence intensity attributed to subsurface damage were observed on the mosaic SCD substrate after MP, while such specific luminescence was not observed after PAP. Micro-Raman spectroscopy measurement showed that peak position shift of diamond Raman lines attributed to residual stress and full width at half maximum (FWHM) broadening attributed to destruction of the crystalline structure were observed on the mosaic SCD substrate after MP, while such a peak position shift and FWHM broadening were not observed after PAP.