Mechanism of photocatalysis-assisted chemical mechanical polishing of CVD single crystal diamond

Abstract

Chemical vapor deposition (CVD) single-crystal diamond has very promising applications in the domains of semiconductors, optical windows, and heat conductivity. However, polishing diamonds is difficult due to their extreme hardness and chemical stability. This study presents a photo catalysis-assisted chemical mechanical polishing (PCMP) approach for creating an ultra-smooth surface on CVD single-crystal diamond. The study used X-ray photoelectron spectroscopy to analyze surface information for the investigation of the PCMP mechanism. The analysis and experimental results reveal that the material removal processes for lapping with larger and smaller abrasives vary. Mechanical action during the PCMP stage enhances the chemical intereaction between carbon and hydroxyl radicals. Diamond carbons are oxidized by hydroxyl radicals ·OH formed on titanium dioxide particles in forms of “C-O”, “C = O” and “O = C-OH”.

Keywords

• photocatalysis
• chemical mechanical polishing
• single crystal diamond
• mechanism