Ultradense gold nanostructures fabricated using hydrogen silsesquioxane resist and applications for surface-enhanced Raman spectroscopy

Metal nanostructures have been routinely fabricated by lift-off process using electron-beam lithography. However, for ultradense structures, this method has been limited by metal film thickness with resulting poor pattern quality. The authors report an alternative approach for the fabrication of ultradense gold (Au) nanostructures using hydrogen silsesquioxane (HSQ). Due to the high resolution and excellent etch durability of HSQ resists, ultradense Au gratings with high quality were fabricated. As a promising application, they demonstrate that these structures can be applied to surface-enhanced Raman scattering (SERS) for bioanalysis. Ultradense Au structures fabricated using HSQ resists have proven to be a robust and effective SERS-active substrate.