Controllable synthesis of core-shell SiO2@CeO2 abrasives for chemical mechanical polishing on SiO2 film

Abstract

The controllable and facile synthesis of SiO2@CeO2 core-shell (CS) composite nanoparticles is crucial for various applications, i.e., chemical mechanical polishing (CMP), nanoreactors, and photocatalysis. However, it is still a challenge to control the synthesis of homogeneous CeO2-coated SiO2 core-shell nanoparticles without additional chemicals or organic solvents. The study investigated the influence of reaction atmosphere, initial pH of the silica colloidal, and the quantity of cerium nitrate on the ceria coating process systematically. Furthermore, the synthesis mechanism of CS composite nanoparticles was ascertained by monitoring changes in pH, zeta potential, secondary size, and morphology over time. The controllable growth of 3%− 67.5% ceria on the surface of silica is realized by controlling the method and timing of adding cerium nitrate and ammonia solution. X-ray photoelectron spectroscopy revealed the Ce-O-Si chemical bonding that combined with the CeO2 at the interfaces of SiO2 core at temperature of 80 °C without post-heating. The material removal rate (MRR) of SiO2 film increased from 32.27 to 294.02 Å/min equipped with CS-7.65% composite nanoparticles as abrasives demonstrated significant improvement. These findings provide valuable insights for the development of SiO2@CeO2 composite nanoparticles in subsequent research.