Ultrahigh-aspect-ratio Si and SiO/sub 2/ deeply-etched periodic structures with extremely smooth surfaces for photonics applications

One-dimensional deeply-etched periodic Si and SiO/sub 2/ structures were fabricated and had excellent vertical profiles (< 0.5 deg.), ultrahigh aspect ratios (/spl sim/ 80) and large etch depths (/spl sim/ 20 /spl mu/m). Low scattering optical loss can be expected by their extremely smooth surfaces.