High-throughput fabrication of infinitely long 10 nm slit arrays for terahertz applications

• Published in: Journal of infrared, millimeter and terahertz waves Vol. 36; no. 3; pp. 262 - 268
• Main Authors: Jeong, Jeeyoon, Rhie, Jiyeah, Jeon, Woojin, Hwang, Cheol Seong, Kim, Dai-Sik
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.03.2015; Springer Nature B.V
• Subjects: Arrays; Atomic layer epitaxy; Chemical treatment; Classical Electrodynamics; Constraining; Deposition; Electrical Engineering; Electronics and Microelectronics; Engineering; High aspect ratio; Infrared; Instrumentation; Organic chemistry; Photolithography; Slits; Solvents; Substrates; Terahertz frequencies; Vulnerability; Fabrication; Terahertz spectroscopy; Terahertz nanotechnology; Field enhancement; Nano-slit
• ISSN: 1866-6892; 1866-6906
• DOI: 10.1007/s10762-014-0135-3

In pursuit of higher field enhancement and applications in terahertz frequency regime, many techniques have been developed and reported for fabrication of high-aspect-ratio metallic nanostructures. While techniques utilizing spacer deposition has successfully overcome the size limit of conventional fabrication tools, they suffer from low throughput or vulnerability to mechanical and chemical treatment, limiting their further application to various fields. In this Letter we report a high-throughput scheme for fabricating metallic gap structures, free from all the aforementioned shortcomings. Vertically aligned gaps are first defined with photolithography and atomic layer deposition, and then made suitable for transmission measurements by etching out predefined sacrificial layers. Existence of the sacrificial layers alleviates many requirements associated with fabrication steps, thereby increasing the overall reliability of the whole process. Using this method we fabricate arrays of 10 nm wide metallic slits whose length is only limited by the substrate size, here 1 cm, and then characterize the sample with terahertz time domain spectroscopy. The sample show steady performance of up to 2500-fold field enhancement even after sonication under various solvents.