New fabrication technique for Si in SiO2 multimetasurface layers

We present a new method of fabricating multi-metasurface layers using a new precise oxidization processing for self-planarization. Our technique uses standard lithography etching/deposition process without mechanical polishing, layer separation/bonding. This method can stream-line process for multi-layers and allow precise alignment between metasurface layers. We have fabricated test samples with two metasurfaces layers of Si nano-strip embedded in SiO2 using this new fabrication method. Preliminary experimental results showed self-planarization of the first metasurface layer and ebeam alignment of the second polysilicon base metasurface on top. This work demonstrated the feasibility of the new fabrication technique and opens the door for future industry commercialization of multi-layer, multi-function metasurface devices/systems.