Grazing incidence diffraction strain anlysis of a laterally modulated multiquantum well system produced by focused ion beam implantation

Focused Ga ion beam implantation was used to define a laterally periodic modulation of the electronic band gap in a GaAs Ga0.97In0.03As Al0.2Ga0.8As GaAs [001] multiquantum well structure. The samples were investigated as implanted and after rapid thermal annealing 60 s at 650 and 800 C by means of x ray grazing incidence diffraction. The method provides a separat inspection of the induced strain and the damage profiles as a function of depth below the sample surface. For samples with an ion dose of 5 times 1013 cm 2 , we found a nearly uniform lateral strain amplitude of about 2 times 10 3 up to the maximum information depth of about 500 nm. It was accompanied by the appearance of structural defects. Rapid thermal annealing at 650 C has reduced the strain amplitude by a factor of five as well as the density of voulme defects. The maximum strain amplitude was found in a depth of about 100 nm. After rapid thermal annealing at 800 C, the strain has disappeare