High-resolution electron beam lithography for the fabrication of high-density dielectric metamaterials

Electron beam lithography has been applied to the fabrication of nanoscale two-dimensional chiral structures with various designs. A fabrication process for planar chiral structures in a thin silicon nitride layer using electron beam lithography and dry etching is presented. A top conductive coating is applied during electron-beam exposure to prevent the occurrence of charging effects caused by the non-conductive silica substrate. Different doses are chosen during the lithography process depending on the complexities and densities of different chiral designs. A very well defined transmission diffraction pattern from arrays of Peano-Gosper fractals is obtained. The optical activity of these dielectric metamaterials shows great potential in their applications of optoelectronic devices and communications