Diffusion of group 1 impurities in epitaxial layers of AlAs-GaAs solid solutions

A study is made of the diffusion of copper, silver, and gold labelled by the corresponding radioactive tracers in epitaxial Alsub(x)Gasub(1-x)As-GaAs heterostructures in the temperature range 800 to 1000 0C. The maximum concentration of impurity is shown to occur in the film-substrate interface region. A similar maximum occurs in the distribution of the dislocation density over the thickness of the structures. The totality of the diffusion, metallographic, electric, and optical studies performed permits to conclude that the ovserved anomalous concentration profiles are caused by interaction of the group 1 impurities with imperfections at the boundaries of epitaxial structures. (author)