Depth dependence of ion implantation damage in AlxGa1−xAs/GaAs heterostructures

To determine the influence of interface type on the accumulation of damage and ion mixing in GaAs/AlxGa1−xAs heterostructures, the damage produced by ion implantation at 77 K in single‐layer (GaAs/AlxGa1−xAs/GaAs) and double‐layer (GaAs/AlxGa1−xAs/GaAs/ AlxGa1−xAs/GaAs) heterostructures has been investigated by using a combination of Rutherford backscattering spectrometry and transmission electron microscopy. In the single‐layer geometry, the degree of disorder increases with depth and the mixing is greater at the AlxGa1−xAs on GaAs interface than at the GaAs on AlxGa1−xAs one. The damage distribution in the sample with the double‐layer geometry was different in the two layers, but overall it was similar to that in the single‐layer geometry. These trends were observed in samples with x=0.6 and 0.2. These results indicate that migration of charged defects due to the presence of an implantation‐induced electric field is not responsible for the asymmetry in the damage accumulation across the layer, the inter...