Surface Grating Fabrication by Inductively Coupled Plasma Dry Etching for InP-Based Photonic Integrated Circuits

Abstract

Surface gratings are widely used in photonic integrated circuits (PICs). In this paper, the authors study the fabrication of surface gratings on indium phosphide (InP) based materials by inductively coupled plasma (ICP) dry etching. The etching parameters are optimized to achieve high aspect ratio while maintaining excellent surface morphology. A novel processing technique is presented for surface grating formation on top of a deeply etched ridge waveguide by taking advantages of the lag effect. Fine structures with non‐uniform height can be completed in a single‐step ICP dry etching, thus greatly simplifying the fabrication by eliminating the demanding overlay process. The method is believe to be valuable for the fabrication of a variety of PICs containing hyperfine structures.

Monolithic Miniature Glass Spectrometer

“…Following this, the grooves were etched to 300 nm using the inductively coupled plasma technique (Plasmapro100 Cobra180, Oxford Instruments) at 9 mTorr pressure with 600 W inductively coupled power, and 35 W radio frequency power, the etch recipe comprising SF 6 , C 4 F 8 , and O 2 . 34 An 80 nm thick silver film was sputtered on the wafer and the 45° reflective prism and grating were glued to the flat plane of the block using a UV adhesive ( n = 1.52). Despite the negligible impact of the refractive index of the UV adhesive on the imaging quality, we incorporated this effect in our Zemax simulation by adding a 100 nm UV curable adhesive layer to the model to achieve a more precise analysis.…”