CH4/H2/N2 reactive ion beam etching for InP based photonic devices

Improved dry etching techniques are crucial for the fabrication of state-of-the-art photonic devices on indium phosphide. One important area is monolithic integration of advanced functions combining ridge and butt-coupling technologies. Reactive ion etching (RIE) of InP-based materials at room temperature with hydrocarbon chemistry is well recognized as an efficient tool, especially for controlling fine pattern etching and anisotropy. Reactive ion beam etching has been studied as an alternative to RTE for which ion energy and current density cannot be controlled independently. This new tool is mainly expected to lead to better etch uniformity on 2-inch InP wafers, to a better control of sidewall angles and a reduction in etched-induced damage. It is currently used with high reproducibility for laser fabrication with methane, hydrogen and argon. In this paper we present process improvements based on nitrogen introduction to reduce polymer deposition. We then show some applications to advanced photonic devices