聚焦离子束（FIB）铣削是一种通用的无掩模和无抗蚀剂图案化技术，已广泛用于制造反等离子体结构，例如用于各种应用的纳米孔和纳米狭缝。然而,由于其减法铣削的性质，这是一个不切实际的方法来制造孤立的等离子体纳米粒子和组件更普遍采用的应用。在这项工作中,我们提出并证明了一种方法，通过简单的“草图和剥离”策略，使用FIB铣削，可靠，快速地定义等离子体纳米颗粒及其组装。系统的实验研究和机理研究表明，由于离子铣削引起的再沉积，保形形成的侧壁涂层使这种制造方法具有高可靠性。特别是,我们证明了这种策略也适用于最先进的氦离子束铣削技术，用它可以直接和快速地原型化具有微小间隙的高保真等离子体二聚体。由于所提出的方法能够快速可靠地图案化通过常规FIB铣削工艺制造不可行的任意等离子体纳米结构,我们的工作为FIB铣削技术提供了额外的纳米图案化能力，因此可以大大提高其在基础研究和器件原型设计中的应用。
Focused ion beam (FIB) milling is a versatile maskless and resistless patterning technique and has been widely used for the fabrication of inverse plasmonic structures such as nanoholes and nanoslits for various applications. However, due to its subtractive milling nature, it is an impractical method to fabricate isolated plasmonic nanoparticles and assemblies which are more commonly adopted in applications. In this work, we propose and demonstrate an approach to reliably and rapidly define plasmonic nanoparticles and their assemblies using FIB milling via a simple \"sketch and peel\" strategy. Systematic experimental investigations and mechanism studies reveal that the high reliability of this fabrication approach is enabled by a conformally formed sidewall coating due to the ion-milling-induced redeposition. Particularly, we demonstrated that this strategy is also applicable to the state-of-the-art helium ion beam milling technology, with which high-fidelity plasmonic dimers with tiny gaps could be directly and rapidly prototyped. Because the proposed approach enables rapid and reliable patterning of arbitrary plasmonic nanostructures that are not feasible to fabricate via conventional FIB milling process, our work provides the FIB milling technology an additional nanopatterning capability and thus could greatly increase its popularity for utilization in fundamental research and device prototyping.
