Optimization of an inductively coupled plasma etching process of GaInP∕GaAs based material for photonic band gap applications

Abstract

In this article, we investigate the dry etching of GaInP∕GaAs based material system using an inductively coupled plasma (ICP) etching system. In a view to develop a suitable ICP process for the etching of aluminum-free material, ridge waveguides have been fabricated and the effects of the ICP parameters have been assessed. The coil power and the platen power have been varied at constant pressure and temperature for a chlorine-based process. The surface quality, sidewall profile, and selectivity have been reported. We also demonstrate the optimization of the chlorine-based process for deep etching and its subsequent implementation in photonic band gap device fabrication for 1.55μm optical applications. The optimized process has been shown to provide a high aspect ratio and a good selectivity for 250nm diam holes with a depth of 3μm in the GaInP∕GaAs material system. The influence of the ICP parameters on this material system have been analyzed mainly by scanning electron microscopy with particular attention drawn to the ways of reducing trenching, an effect commonly associated with ICP etching.