Depth profile of the implantation-enhanced intermixing of Ga+ focused ion beam in AlAs/GaAs quantum wells

The implantation-induced intermixing depth profile for 100 keV Ga+ ions was determined by photoluminescence measurements on a series of samples containing quantum wells at variable depth from the surface but identical thickness. They were uniformly implanted and subsequently a rapid thermal annealing was applied. The measured maximum of the intermixing occurred at a depth of about 70 nm, significantly deeper than theoretical predictions. These results are important for achieving sufficient intermixing with a low implantation dose, thereby optimizing crystal quality and lateral resolution.