Institute for Applied Physics, University of Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen, Germany. Center for Light-Matter-Interaction, Sensors and Analytics LISA+, University of Tübingen, Auf der Morgenstelle 15, D-72076 Tübingen, Germany.
Nanotechnology. 2019 Jun 7;30(23):235302. doi: 10.1088/1361-6528/ab0506.
Milling with the focused helium ion beam of a helium ion microscope is one of the most accurate ways to produce nano-structures such as plasmonic nanoantennas. In addition to good and immediate control of the dimensions, features in the sub-10 nm regime are achievable. Especially small gaps and sharp tips in this regime may lead to very high field enhancement under excitation. However, the milling rate of 30 keV helium ions is rather low, making it time-consuming to cut nano-structures out of a gold film. We present two processes to work around the low milling rate to obtain arrays of nano-structures with maximum precision within a reasonable time. These strategies can both be adapted to either poly-crystalline gold films or single-crystalline gold flakes. Using single crystals from a fabrication point of view enables even higher precision due to constant etch rates over the whole crystal as well as straight edges and vertical side-walls due to the uniform crystalline structure.
使用氦离子显微镜的聚焦氦离子束进行铣削是制造等离子体纳米天线等纳米结构的最精确方法之一。除了能够很好地即时控制尺寸外，还可以实现亚 10nm 尺度的特征。在这个尺度下，特别是小间隙和尖锐尖端可能会导致在激发下产生非常高的场增强。然而，30keV 氦离子的铣削速率相当低，因此从金膜中切割纳米结构非常耗时。我们提出了两种克服低铣削速率的方法，以在合理的时间内获得具有最大精度的纳米结构阵列。这两种策略都可以适应多晶金膜或单晶金薄片。从制造的角度来看，使用单晶可以实现更高的精度，因为整个晶体的蚀刻速率是恒定的，并且由于晶体结构的均匀性，边缘是直的，侧壁是垂直的。
