McClelland J J, Steele A V, Knuffman B, Twedt K A, Schwarzkopf A, Wilson T M
Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899.
Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899; zeroK NanoTech, Gaithersburg, MD 20878.
Appl Phys Rev. 2016 Mar;3(1). doi: 10.1063/1.4944491. Epub 2016 Mar 24.
Nanoscale focused ion beams (FIBs) represent one of the most useful tools in nanotechnology, enabling nanofabrication via milling and gas-assisted deposition, microscopy and microanalysis, and selective, spatially resolved doping of materials. Recently, a new type of FIB source has emerged, which uses ionization of laser cooled neutral atoms to produce the ion beam. The extremely cold temperatures attainable with laser cooling (in the range of 100 μK or below) result in a beam of ions with a very small transverse velocity distribution. This corresponds to a source with extremely high brightness that rivals or may even exceed the brightness of the industry standard Ga liquid metal ion source. In this review we discuss the context of ion beam technology in which these new ion sources can play a role, their principles of operation, and some examples of recent demonstrations. The field is relatively new, so only a few applications have been demonstrated, most notably low energy ion microscopy with Li ions. Nevertheless, a number of promising new approaches have been proposed and/or demonstrated, suggesting that a rapid evolution of this type of source is likely in the near future.
纳米级聚焦离子束（FIB）是纳米技术中最有用的工具之一，可通过铣削和气体辅助沉积、显微镜检查和微分析以及材料的选择性、空间分辨掺杂实现纳米制造。最近，出现了一种新型的FIB源，它利用激光冷却的中性原子的电离来产生离子束。激光冷却可达到的极低温度（在100μK或更低的范围内）导致离子束的横向速度分布非常小。这对应于一个具有极高亮度的源，其亮度可与甚至可能超过行业标准的镓液态金属离子源的亮度。在本综述中，我们讨论了这些新离子源可以发挥作用的离子束技术背景、它们的工作原理以及最近一些演示的例子。该领域相对较新，因此仅展示了少数应用，最显著的是锂离子低能离子显微镜。然而，已经提出和/或展示了许多有前途的新方法，这表明这种类型的源在不久的将来可能会迅速发展。
