Nanolithography-Free Wafer-Scale Precise Manufacturing of Nanogap Electrodes for Functional Applications

Nanogap electrodes (NGEs) possess rich physical and chemical properties, hold immense potential across domains, including molecular electronics, flexible electronics, nanoscale vacuum devices, and other emerging nanoelectronics. However, traditional fabrication techniques encounter challenges in achieving heterogeneous electrodes, high batch-to-batch consistency, and cost-effective, high-yield, scalable production, hindering the practical utilization of NGEs. This paper introduces an optimized oblique deposition process that addresses these challenges by enabling fine control of gap sizes in NGEs ranging from sub-10 nm to several hundred nanometers without the need for high-resolution nanolithography, while enhancing device uniformity. The proposed method achieves an outstanding depth-height ratio (1:6.9) and an exceptionally high aspect ratio (1:30,000) in ultra-small gaps of 8 nm, surpassing current technological capabilities. It demonstrates excellent scalability on 4-inch silicon wafers, with high success rates and repeatability. Moreover, the process facilitates the fabrication of fabricating heterogeneous electrodes, showcasing outstanding versatility across different substrates and structures. This investigation successfully illustrates the application of the proposed oblique deposition process in wafer-level nanoscale vacuum devices (NVDs) and proves that the NVDs fabricated using this method exhibit outstanding electrical characteristics and stability. These advancements expand the potential applications of NGEs and pave the way for their contributions in various technological domains.