Low-Damage Reactive Ion Etching of Nanoplasmonic Waveguides with Ultrathin Noble Metal Films

Abstract

Nanoplasmonic waveguides utilizing surface plasmon polaritons (SPPs) propagation have been investigated for more than 15 years and are now well understood. Many researchers make their efforts to find the best ways of using light and overcoming the speed limit of integrated circuits by means of SPPs. Here, we introduce the simulation results and fabrication technology of dielectric-metal-dielectric long-range nanoplasmonic waveguides, which consists of a multilayer stack based on ultrathin noble metals in between alumina thin films. Various waveguide topologies are simulated to optimize all the geometric and multilayer stack parameters. We demonstrate the calculated propagation length of Lprop = 0.27 mm at the 785 nm wavelength for the Al2O3/Ag/Al2O3 waveguides. In addition, we numerically show the possibility to eliminate signal cross-talks (less than 0.01%) between two crossed waveguides. One of the key technology issues of such waveguides’ nanofabrication is a dry, low-damage-etching of a multilayer stack with extremely sensitive ultrathin metals. In this paper, we propose the fabrication process flow, which provides both dry etching of Al2O3/Au(Ag)/Al2O3 waveguides nanostructures with high aspect ratios and non-damage ultrathin metal films patterning. We believe that the proposed design and fabrication process flow provides new opportunities in next-generation photonic interconnects, plasmonic nanocircuitry, quantum optics and biosensors.

Optical hydrogen sensing with high-Q guided-mode resonance of Al2O3/WO3/Pd nanostructure

“…After the first step, the e-beam resist masks were removed. On the second step, Al 2 O 3 layers etching was carried out using chlorine gases (BCl 3 and Cl 2 mixture) plasma 39 with the following tungsten mask removal in a fluorine gases plasma. After that, the Al 2 O 3 gratings were covered by an e-beam evaporation with 110 nm thick tungsten oxide (WO 3 ) layer at a rate of 0.50 nm/s and oxygen partial pressure of Torr and 1 nm palladium (Pd) layer at a rate of 0.025 nm/s.…”