Abasahl B, Santschi C, Raziman T V, Martin O J F
Nanophotonics and Metrology Laboratory, Swiss Federal Insititute of Technology Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
Nanotechnology. 2021 Aug 31;32(47). doi: 10.1088/1361-6528/ac1a93.
After providing a detailed overview of nanofabrication techniques for plasmonics, we discuss in detail two different approaches for the fabrication of metallic nanostructures based on e-beam lithography. The first approach relies on a negative e-beam resist, followed by ion beam milling, while the second uses a positive e-beam resist and lift-off. Overall, ion beam etching provides smaller and more regular features including tiny gaps between sub-parts, that can be controlled down to about 10 nm. In the lift-off process, the metal atoms are deposited within the resist mask and can diffuse on the substrate, giving rise to the formation of nanoclusters that render the nanostructure outline slightly fuzzy. Scattering cross sections computed for both approaches highlight some spectral differences, which are especially visible for structures that support complex resonances, such as Fano resonances. Both techniques can produce useful nanostructures and the results reported therein should guide the researcher to choose the best suited approach for a given application, depending on the available technology.
在详细概述了用于等离子体激元学的纳米制造技术之后，我们详细讨论了基于电子束光刻制造金属纳米结构的两种不同方法。第一种方法依赖于负性电子束抗蚀剂，随后进行离子束铣削，而第二种方法使用正性电子束抗蚀剂和剥离工艺。总体而言，离子束蚀刻能够提供更小且更规则的特征，包括子部件之间的微小间隙，这些间隙可控制至约10纳米。在剥离过程中，金属原子沉积在抗蚀剂掩膜内并可在衬底上扩散，从而导致纳米团簇的形成，使纳米结构轮廓略显模糊。针对这两种方法计算的散射截面突出了一些光谱差异，对于支持复杂共振（如法诺共振）的结构而言，这些差异尤为明显。这两种技术都能制造出有用的纳米结构，其中报道的结果应能指导研究人员根据现有技术，为特定应用选择最合适的方法。
