Authors: A. Koeck, R. Hainberger, R. Heer, M. Kast, T. Maier and C. Stepper
Affilation: ARC Seibersdorf research GmbH, Austria
Pages: 66 - 69
Keywords: nanosensors, nanobelts, nanophotonics
Electrical and optical nanosensors for biomedical diagnostics and biochemical analytics are developed. The electrical and optical nanosensors employ nanobelt, nanowire and nanogap structures fabricated on silicon-on-insulator (SOI) wafers. In SOI wafers, a thin silicon layer is separated by a silicon oxide layer from the bulk. An optimized dry etching process allows the removal of both the top silicon layer and the SiO2 in order to yield the nanobelt and nanowire shapes. The SiO2 layer is finally removed, which results in free standing nanobelts and nanowires and in nanogaps. The optical nanosensors are based on planar integrated waveguide structures and silicon photonic wires fabricated from SOI wafers. While the light propagates in the waveguide layer, part of the optical field penetrates into the surrounding cladding layers. When the upper cladding is an aqueous analyte, specific type of molecules can be captured by a biosensitive layer on top of the silicon waveguide, which can be detected with high sensitivity by an integrated Mach-Zehnder-interferometer structure. Simulation tools for the calculation of the sensitivity and the mode behavior as a function of the waveguide geometry were developed and used in order to optimize the sensing performance.