Measurement of the depth distribution of ion beam etching-induced damage in AlGaAs/GaAs multiple quantum well structure

The defect depth distribution caused by a 500 eV nitrogen ion beam etching (IBE) of an Al0.35Ga0.65As/GaAs multiple quantum well (MQW) structure was investigated by confocal photoluminescence (PL) measurements on a beveled section of the sample. The beveled section with an extremely small inclination angle necessary for the high depth resolution was fabricated by the IBE itself. Compared to other ion beam or plasma assisted etching processes reported, e.g., Ar-IBE, the 500 eV nitrogen IBE yields a very low defect density. A model including diffusion effects for the description of the profile gives a value of 4×10−15 cm2 /s for the defect diffusion coefficient.