Influence of Ge and Si on Reactive Ion Etching of GaN in Cl2 Plasma

Abstract

We investigated the influence of Ge and Si in Cl2 plasma on reactive ion etching (RIE) of GaN. The etched surfaces of GaN were smooth, and high etch rates of 0.63 µm/min and 0.41 µm/min were obtained using a Ge plate and a Si plate, respectively. A rough surface was formed for the quartz plate without the Ge plate or Si plate. Optical emission spectroscopy revealed optical emissions related to GeClx+ ions in Cl2 plasma with the Ge plate, to SiClx+ ions with the Si plate and to Cl+ ions without the Ge or Si plate. It is considered that the GeClx+ ions and SiClx+ ions for RIE of GaN play an important role in obtaining a smooth etched surface of GaN, and that the high-energy Cl+ ion severely damages the GaN surface.