C12/02- and Cl2-based Inductively Coupled Plasma Etching of Photonic Crystals in InP: Sidewall Passivation

We have fabricated two-dimensional photonic crystals in InP-based materials with Clz-based inductively coupled plasma etching. To obtain vertical sidewalls, we employ sidewall passivation through addition of Nz or U2 to the plasma. With the Clz/Oz-process we are able to etch 3.2 pm deep holes that have nearly cylindrical shape in the upper 2 pm. The first optical results illustrate the feasibility of our approach, showing over 30 dB transmission reduction in the rK-stopband