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

摘要

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 120 nm half-pitch gratings with 2000 nm depth and built-in 1 mm pitch bulk silicon support structures. Optical characterization demonstrates 10~(-4) transmission of UV in the 190–250 nm band while a 25–30% geometric transparency allows particles to pass unimpeded for space plasma measurements.