Hanssen James L, Hill Shannon B, Orloff Jon, McClelland Jabez J
Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
Nano Lett. 2008 Sep;8(9):2844-50. doi: 10.1021/nl801472n. Epub 2008 Aug 21.
We report on the demonstration of a low emittance, high brightness ion source based on magneto-optically trapped neutral atoms. Our source has ion optical properties comparable to or better than those of the commonly used liquid metal ion source. In addition, it has several advantages that offer new possibilities, including high resolution ion microscopy with ion species tailored for specific applications, contamination-free ion milling, and nanoscale implantation of a variety of elements, either in large quantities, or one at a time, deterministically. Using laser-cooled Cr atoms, we create an ion beam with a normalized rms (root-mean-square) emittance of 6.0 x 10 (-7) mm mrad M e V and approximately 0.25 pA of current, yielding a brightness as high as 2.25 A cm (-2) sr (-1) eV (-1). These values of emittance and brightness show that, with suitable ion optics, an ion beam with a useful amount of current can be produced and focused to spot sizes of less than 1 nm.
我们报道了一种基于磁光阱中性原子的低发射度、高亮度离子源的演示。我们的离子源具有与常用液态金属离子源相当或更好的离子光学特性。此外，它还有几个优点，提供了新的可能性，包括用于特定应用的定制离子种类的高分辨率离子显微镜、无污染离子铣削以及多种元素的纳米级注入，既可以大量注入，也可以一次注入一个，具有确定性。使用激光冷却的铬原子，我们产生了一个归一化均方根（rms）发射度为6.0×10^(-7) 毫米·毫弧度·兆电子伏特且电流约为0.25皮安的离子束，产生了高达2.25安·厘米^(-2)·球面度^(-1)·电子伏特^(-1)的亮度。这些发射度和亮度值表明，通过合适的离子光学系统，可以产生具有有用电流的离子束，并将其聚焦到小于1纳米的光斑尺寸。
