Precision Polishing of Single Crystal Diamond (111) Substrates Using a Sol-Gel (SG) Polishing Pad

In recent years, the application prospect of single crystal diamond (SCD) in the field of electronics is remarkable, and material processing technologies are the basis for the application of semiconductor materials. In this paper, a novel polishing method for SCD substrates was developed utilizing a sol-gel (SG) polishing pad, which is a semi-fixed abrasive polishing tool fabricated by SG technique. The surface morphology of SCD substrates was observed with a 3-D optical profiler and scanning electron microscopy (SEM). The results showed that the surface roughness was 1.32 nm Ra and the material removal rate of SCD (111) was about 120 nm/h. The polished diamond surfaces and wear debris were investigated using Raman spectroscopy and transmission electron microscopy (TEM), respectively. The results showed the removal mechanism of SCD using an SG polishing pad was mainly dominated by the mechanical removal and phase transformation, including the mechanical cleavage, amorphization, and graphitization.