Fabrication of metallic nanostructures for investigating plasmon-induced field enhancement

• Published in: Microelectronic engineering 2007-05, Vol.84 (5), p.1589-1592
• Main Authors: Stade, F., Heeren, A., Fleischer, M., Kern, D.P.
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit properties; E-beam lithography; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Hydrogen silsesquioxane; Integrated optics. Optical fibers and wave guides; Ion milling; Microelectronic fabrication (materials and surfaces technology); Optical and optoelectronic circuits; Plasmonics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2007.01.256

High resolution metallic nanostructures with well-defined geometry, such as antennae, cones and rods, are essential for nanophotonics and plasmonics. In order to fabricate such structures, we use the negative electron beam resist hydrogen silsesquioxane (HSQ) as an etch mask for an underlying metal stack. By exposing the resist and developing it in tetramethyl ammonium hydroxide (TMAH), structures with dimensions of few tens of nanometers can be fabricated. Afterwards the surrounding metal is removed by ion milling. Finally, the HSQ is lifted off via a sacrificial chromium layer. The process was used to fabricate arrays of cones and antennae of different sizes, either resonant for optical or for infrared wavelengths. Furthermore simulations of the electric field in the vicinity of the metal nanostructures were performed using the finite element method.