Large area direct nanoimprinting of SiO2–TiO2 gel gratings for optical applications

Abstract

We demonstrated an economical way of fabricating gel–film-based devices by combining nanoimprint lithography (NIL) and a sol–gel technique. A novel imprinting procedure, new mold surface passivation, and an effective surfactant added to sol were developed. Gratings with 300 nm pitch and 80 nm linewidth and waveguide gratings with varying periods were imprinted in a single step and with excellent uniformity into the gel films coated on a quarter of 4 in. wafers, respectively. Surface roughness measurements of waveguide gratings by atomic force microscope showed smooth profiles with root mean square roughness less than 6 nm. NIL is an excellent patterning technology for gel–film-based optical devices.