Compositional disordering and the formation of semi-insulating layers in AlAs-GaAs superlattices by MeV oxygen implantation

Data are presented demonstrating the use of MeV oxygen ion implantation and subsequent annealing procedures to induce compositional disordering and to create a semiinsulating region simultaneously within an AlAs-GaAs superlattice. High dose oxygen implantation yields a compositionally disordered region 3500Å wide centered 1.25 µm below the surface of the superlattice, as determined by secondary ion mass spectrometry (SIMS) analysis. More extensive disordering of the superlattice occurs at lower implantation temperatures. Current-voltage measurements indicate the formation of a semiinsulating layer which is thermally stable to at least 850° C. The semi-insulating properties of the implanted superlattice are assigned to the disorder-enhanced formation of Al-O pairs and the substitutional introduction of deep level states.