Large-scale synthesis of water dispersible ceria nanocrystals by a simple sol-gel process and their use as a chemical mechanical planarization slurry

Ceria nanocrystals with a cube shape were synthesized from the hydrolytic sol-gel reaction of cerium salt in the presence of oleylamine. The overall synthetic process is very simple and readily applicable to the large-scale synthesis of tens of grams of product in a single reaction in air. These ceria nanocrystals are readily dispersible in aqueous media without the addition of any extra dispersing agent. The aqueous dispersion of the ceria nanocrystals was successfully used as a chemical mechanical polishing slurry, and it exhibited high removal selectivity between silicon oxide and silicon nitride at pH 7.