GaAs Taper Etching by Mixture Gas Reactive Ion Etching System

A novel technique is proposed for taper-etching GaAs. The angle of the sidewalls formed by undercutting GaAs can be controlled by adjusting the ratio of He to CCl 2 F 2 used for reactive ion etching (RIE). A negative undercut with a taper angle of 80 degrees is formed with He gas content of 95%. Etched surfaces are analyzed by micro-Auger spectroscopy. The detailed etching conditions for forming taper shapes are described and the mechanism of such formation is also discussed.