Grazing-incidence diffraction strain analysis 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 m odulation of the electronic band gap in a GaAs/Ga0.97In0.03As/Al0.2Ga0.8As/ GaAs [001] multiquantum well structure. The samples were investigated as-im planted and after a rapid thermal annealing (60 s at 650 and 800 degreesC) by means of x-ray grazing-incidence diffraction. The method provides a sepa rate 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 5x10(13 ) cm(-2), we found a nearly uniform lateral strain amplitude of about 2x10( -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 de greesC has reduced the strain amplitude by a factor of five as well as the density of volume defects. The maximum strain amplitude were found in a dep th of about 100 nm. After rapid thermal annealing at 800 degreesC, the stra in has disappeared. (C) 2000 American Institute of Physics. [S0003-6951(00) 01051-2].