Reactive ion etching-induced damage in GaAs/AlGaAs quantum well structures and recovery by rapid thermal annealing and hydrogen passivation

Reactive ion etching (RIE)-induced damage in a GaAs/AlGaAs quantum well structure, consisting of four GaAs quantum wells with different thicknesses, has been investigated by photoluminescence (PL). RIE was performed using a mixture of He and CCl2F2 gases under a variety of etching conditions. The PL intensities from the quantum wells damaged under an etching condition of physical sputtering decrease uniformly across the depth through the sample. The reduced PL intensities from the damaged quantum wells are restored by rapid thermal annealing and hydrogen plasma treatment. In particular, PL intensities from the quantum wells situated at the deep region from the surface are more drastically recovered than those from the near surface region. This result suggests that the decreases in the PL intensities created in the deep region have different recovery efficiencies from those at the near surface region. It is indicated also that the defects in the deep region are closely related to the vacancies of sublattice, particularly when light ions are involved in the etching process.