Fabrication and testing of freestanding Si nanogratings for UV filtration on space-based particle sensors

Abstract

We demonstrate complete fabrication process integration and device performance of sturdy, self-supported transmission gratings in silicon. Gratings are patterned with nanoimprint lithography and aluminum liftoff on silicon-on-insulator wafers. Double-sided deep reactive ion etching (DRIE) creates freestanding 120nm half-pitch gratings with 2000nm depth and built-in 1mm pitch bulk silicon support structures. Optical characterization demonstrates 10 4 transmission of UV in the 190250nm band while a 25 30% geometric transparency allows particles to pass unimpeded for space plasma measurements.