C.F. Carlström

InP-based two-dimensional photonic crystals filled with polymers

Polymer filling of the air holes of indium-phosphide-based two-dimensional photonic crystals is reported. After infiltration of the holes with a liquid monomer and solidification of the infill in situ by thermal polymerization, complete filling is proven using scanning electron microscopy. Optical transmission measurements of a filled photonic crystal structure exhibit a redshift of the air band, confirming the complete filling.

Cl2∕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 1550nm. 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 0.25μm. 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.

Inductively coupled plasma etching of deep photonic crystal holes in InP using Cl/sub 2/

We have investigated ICP-etching of deep photonic crystal holes in InP using solely Cl2 as supplied etching gas. The influence of process parameters on hole geometry is discussed and optical test results are reported

Deep Hole InP Photonic Crystals Infiltrated With Solid Polymers And Liquid Crystals

A procedure to etch deep photonic crystal holes in InGaAsP and subsequently fill them with a low index material such as liquid crystal or a solid polymer has been developed. Successful infiltration was proven by optical transmission measurement and in the case of solid polymer also by cross section inspection.

Cl/sub 2//O/sub 2/- and Cl/sub 2//N/sub 2/-based inductively coupled plasma etching of photonic crystals in InP: sidewall passivation

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