CMOS-Compatible Top-Down Fabrication of Periodic SiO2 Nanostructures using a Single Mask

Abstract

(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.We propose a CMOS-compatible top-down fabrication technique of highly-ordered and periodic SiO2 nanostructures using a single amorphous silicon (α-Si) mask layer. The α-Si mask pattern is precisely transferred into the underlying SiO2 substrate material with a high fidelity by a novel top-down fabrication. It is the first time for α-Si film used as an etch mask to fabricate SiO2 nanostructures including nanoline, nanotrench, and nanohole arrays. It is observed that the α-Si mask can significantly reduce the pattern edge roughness and achieve highly uniform and smooth sidewalls. This behavior may be attributed to the presence of high concentration of dangling bonds in α-Si mask surface. By controlling the process condition, it is possible to achieve a desired vertical etched profile with a controlled size. Our results demonstrate that SiO2 pattern as small as sub-20 nm may be achievable. The obtained SiO2 pattern can be further used as a nanotemplate to produce periodic or more complex silicon nanostructures. Moreover, this novel top-down approach is a potentially universal method that is fully compatible with the currently existing Si-based CMOS technologies. It offers a greater flexibility for the fabrication of various nanoscale devices in a simple and efficient way.

Observation of Enhanced Optical Spin Hall Effect in a Vertical Hyperbolic Metamaterial

“…Although period of the grating is not small enough to satisfy effective medium theory in our experiment, the transverse shift of a micrometerscale is obtained. The optical spin Hall effect of a vertical hyperbolic metamaterial with period much smaller than the wavelength can be demonstrated by scaling down the period by adopting sophisticated fabrication techniques 25 or in terahertz regime using the current technology. The huge optical spin Hall effect in a vertical hyperbolic metamaterial provides a way to realize compact photonic devices with spin degree-of-freedom such as filters, sensors, switches, and beam splitters.…”