Physical and chemical changes in the surface layer of GaAs induced by recoil implantation of Al atoms

Physical and chemical changes in the surface layer of GaAs induced by recoil implantation of Al atoms and upon annealing are investigated by secondary ion mass spectrometry (SIMS), Auger electron spectroscopy (AES), Rutherford backscattering spectrometry (RBS), as well as by C-U measurements and IR spectra. Recoil implantation of Al is carried out by irradiation of Al/n-GaAs structures with argon (Ar+) ions, at doses between 1014 and 1016 cm-2. The energy is selected so that the projected depth would not exceed the thickness of the Al film. Recoil implantation of Al atoms into the surface layer of GaAs is found to lead to the preferential removal of Ga atoms from the surface of GaAs with subsequent accumulation of these atoms on the surface of the metal film. At the same time creation of acceptor-like simple defects is detected, which anneal in two steps, at temperatures of 450 and 820 K. (author)