Improvement in low energy ion-induced damage with a low temperature GaAs capping layer

A thin capping layer of annealed GaAs (similar to 210 Angstrom) grown at low temperature (LT-GaAs) can effectively block incident ions from penetrating into the growth substrate. Ion-bombarded, multiple quantum well structures capped by an annealed LT-GaAs layer show a dramatic improvement in the photoluminescence, compared to samples capped with ''normal'' GaAs. The improvement appears to be correlated with the microstructures of the LT-GaAs, since the improvement is particularly notable for samples annealed at 600 degrees C. This improvement in low energy ion-induced damage is primarily the result of the reduced channeling of ions through the LT-GaAs layer. These results suggest a potential application of LT-GaAs in reducing ion damage and underscore the importance of the microstructure of arsenic precipitates in LT-GaAs layers. (C) 1996 American Institute of Physics.