Converting ceria polyhedral nanoparticles into single-crystal nanospheres
Converting ceria polyhedral nanoparticles into single-crystal nanospheres
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DOI：
10.1126/science.1125767
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发表时间：
2006-06-09
期刊：
影响因子：
56.9
通讯作者：
Her, Yie-Shein
中科院分区：
文献类型：
--
作者：
Feng, Xiangdong;Sayle, Dean C.;Her, Yie-Shein
二氧化铈纳米粒子是先进集成电路化学机械平坦化的关键研磨材料之一。然而，现有技术合成的二氧化铈纳米粒子是不规则的刻面，它们会划伤硅片并增加缺陷浓度。我们开发了一种大规模合成单晶二氧化铈纳米球的方法，可以减少80%的抛光缺陷，提高50%的二氧化硅去除率，有利于纳米电子芯片的精确、可靠的大规模制造。我们在二氧化铈系统中掺杂了钛，使用的火焰温度有利于二氧化铈的结晶，同时使二氧化钛保持在熔融状态。结合分子动力学模拟，我们表明，在这些条件下，二氧化铈内部核演化为单晶球形，没有刻面，因为在整个结晶过程中，它完全被熔融的 1 至 2 纳米二氧化钛壳包裹，在液态下，二氧化钛壳使表面能最小化。这里演示的原理可以应用于其他氧化物系统。
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.