Scan speed effects on enhanced disordering of GaAs-AlGaAs superlattices by focused Si ion beam implantation

We studied compositional disordering of GaAs-AlGaAs superlattices induced by focused Si ion beam implantation and subsequent annealing with different doses and scan speeds by secondary ion mass spectrometry and Rutherford backscattering spectrometry. The results indicate that the Al-Ga intermixing is enhanced by substitutional exchange of Si-Si pairs with vacancies as in the case of the unfocused implantation. However, with a slow scan implantation, it is confirmed that the implantation-induced defects suppress the Si diffusion and consequently Al-Ga interdiffusion.