Fabrication of stereo metallic resonant structures with polymer droplets as template

Using polymer droplets formed in dewetting of polymer film on silicon surface as template, the silicon columns capped with circular polymer plates are fabricated via plasma etching. By blanket deposition of a gold layer on the structure, an array of metallic microcavities featured by a metal circular plate separated by a silicon column with the bottom metallic film is achieved. The geometrical parameters of the stereo structures can be tuned. We show that the electric field at the edge of the cap is greatly enhanced, which can be used as the hot spot for trace amount of chemical detection.