Sub-10 nm fabrication: methods and applications

Reliable fabrication of micro/nanostructures with sub-10 nm features is of great significance for advancing nanoscience and nanotechnology. While the capability of current complementary metal-oxide semiconductor (CMOS) chip manufacturing can produce structures on the sub-10 nm scale, many emerging applications, such as nano-optics, biosensing, and quantum devices, also require ultrasmall features down to single digital nanometers. In these emerging applications, CMOS-based manufacturing methods are currently not feasible or appropriate due to the considerations of usage cost, material compatibility, and exotic features. Therefore, several specific methods have been developed in the past decades for different applications. In this review, we attempt to give a systematic summary on sub-10 nm fabrication methods and their related applications. In the first and second parts, we give a brief introduction of the background of this research topic and explain why sub-10 nm fabrication is interesting from both scientific and technological perspectives. In the third part, we comprehensively summarize the fabrication methods and classify them into three main approaches, including lithographic, mechanics-enabled, and post-trimming processes. The fourth part discusses the applications of these processes in quantum devices, nano-optics, and high-performance sensing. Finally, a perspective is given to discuss the challenges and opportunities associated with this research topic.