Smooth vertical etching of AlGaInP by Cl 2 reactive ion beam etching

Very smooth vertical etching of AlGaInP is achieved for the first time by Cl2 reactive ion beam etching. The etched depth is precisely controlled (σ = 22 nm) by simply monitoring the electrode current of the ion accelerating grid, and the etched surface exhibits no contamination except for Cl, as observed by in situ Auger electron spectroscopy. Furthermore, other III-V compound semiconductors, such as AlGaInP/GaInP double heterostructures and InAlAs/InGaAs/InP multilayers, are also etched smoothly and vertically with no steps between the layers on the sidewalls.