title: Converting ceria polyhedral nanoparticles into single-crystal nanospheres.
abstract: Ceria nanoparticles are one of the key abrasive materials for chemical-mechanical planarization of advanced integrated circuits. However, ceria nanoparticles synthesized by existing techniques are irregularly faceted, and they scratch the silicon wafers and increase defect concentrations. We developed an approach for large-scale synthesis of single-crystal ceria nanospheres that can reduce the polishing defects by 80% and increase the silica removal rate by 50%, facilitating precise and reliable mass-manufacturing of chips for nanoelectronics. We doped the ceria system with titanium, using flame temperatures that facilitate crystallization of the ceria yet retain the titania in a molten state. In conjunction with molecular dynamics simulation, we show that under these conditions, the inner ceria core evolves in a single-crystal spherical shape without faceting, because throughout the crystallization it is completely encapsulated by a molten 1- to 2-nanometer shell of titania that, in liquid state, minimizes the surface energy. The principle demonstrated here could be applied to other oxide systems.
authors.affiliation: Ferro Corporation, 7500 East Pleasant Vally Road, Independence, OH 44131, USA. shawn.feng@jhresearchusa.com
authors.forename: Xiangdong
authors.initials: X
authors.lastname: Feng
authors.forename: Dean C
authors.initials: DC
authors.lastname: Sayle
authors.forename: Zhong Lin
authors.initials: ZL
authors.lastname: Wang
authors.forename: M Sharon
authors.initials: MS
authors.lastname: Paras
authors.forename: Brian
authors.initials: B
authors.lastname: Santora
authors.forename: Anthony C
authors.initials: AC
authors.lastname: Sutorik
authors.forename: Thi X T
authors.initials: TX
authors.lastname: Sayle
authors.forename: Yi
authors.initials: Y
authors.lastname: Yang
authors.forename: Yong
authors.initials: Y
authors.lastname: Ding
authors.forename: Xudong
authors.initials: X
authors.lastname: Wang
authors.forename: Yie-Shein
authors.initials: YS
authors.lastname: Her