Freely suspended nanostructure with no substrate beneath: fabrication and optical imaging

Nano electromechanical systems (NEMS) were fabricated out of silicon on insulator material. The NEMS structures were reliably located on top of a hole leading through the whole substrate etched using bulk processing. The structures therefore are fully freely suspended and thus have no substrate beneath them that could interfere with the NEMS operation, e.g. electrostatically. Structures of 10 μm×200 nm×120 nm were fabricated. Confocal optical microscopy was used to image these nanostructures. Despite the wavelength of 635 nm, the structures of 200 nm width were clearly resolved and a separation of about 200 nm between two beams could also be roughly identified. In contrast to scanning electron microscopy (SEM) imaging, the optical imaging is absolutely damage free and can be easily carried out under ambient conditions.