GaAs Radical Etching with a Cl2 Plasma in a Reactive Ion Beam Etching System

GaAs radical etching, similar to that reported with a Br2 plasma in a reactive ion etching system, has been confirmed in a Cl2 gas reactive ion beam etching system for the first time. Ion bombardment was completely suppressed with a sample faced opposite to the ion source. Etching rates at substrate temperatures of 300 to 400°C were 30 Å/min to 10µm/min. The etched surface was very smooth and showed crystallographic orientation to expose the {111}A facet. Apparent activation energy was about 500 kcal/mol. It is expected that a damage- and contamination-free surface can be obtained by this radical etching technique.