Comparative study of Cl₂, Cl₂/O₂, and Cl₂/N₂ inductively coupled plasma processes for etching of high-aspect-ratio photonic-crystal holes in InP

An extensive investigation has been performed on inductively coupled plasmaetching of InP. An important motivation for this work is the fabrication of high-aspect-ratio holes for photonic crystals. The essential chemistry is based on Cl₂ with the addition of N₂ or O₂ for sidewall passivation. The influence of different process parameters such as gas flows, temperature,pressure, ion energy, and inductively coupled plasma power on the hole geometry is presented. It is concluded that photonic crystals can be etched with Cl₂ only; however, temperature and pressure control is critical. Adding passivation gases largely broadens the window in the parameter space for hole etching. Most importantly, etching of narrow holes can be carried out at higher temperatures where the etching is mass limited and spontaneous etching of InP by Cl₂ occurs.Part of this research is supported by NanoNed, a technology program of the Dutch Ministry of Economic Affairs

CI2/O2-inductively coupled plasma etching of deep hole-type photonic crystals in InP

We have developed an inductively coupled plasma etching process for fabrication of high-aspect-ratio hole-type photonic crystals in InP, which are of interest for optical devices involving the telecommunication wavelength of 1550 nm. The etching was performed at 250 °C using Cl2/O2 chemistry for sidewall passivation. The process yields nearly cylindrical features with an aspect ratio larger than 10 for hole diameters near 0.25 µm. This makes them very suitable for high-quality photonic crystal patterns

Comparative study of Cl2, Cl2/O2, and Cl2/N2 inductively coupled plasma processes for etching of high-aspect-ratio photonic-crystal holes in InP

An extensive investigation has been performed on inductively coupled plasma etching of InP. An important motivation for this work is the fabrication of high-aspect-ratio holes for photonic crystals. The essential chemistry is based on Cl2 with the addition of N2 or O2 for sidewall passivation. The influence of different process parameters such as gas flows, temperature, pressure, ion energy, and inductively coupled plasma power on the hole geometry is presented. It is concluded that photonic crystals can be etched with Cl2 only; however, temperature and pressure control is critical. Adding passivation gases largely broadens the window in the parameter space for hole etching. Most importantly, etching of narrow holes can be carried out at higher temperatures where the etching is mass limited and spontaneous etching of InP by Cl2 occurs.QN/Quantum NanoscienceApplied Science