Al-o Complex-formation In Ion-implanted Czochralski and Floating-zone Si Substrates

Aluminum ions at 100 MeV were implanted into floating-zone (FZ) and Czochralski (CZ) grown Si substrates. At this energy the influence of the surface on the subsequent thermal treatment is negligible. In FZ samples the electrical active dose, as measured by spreading resistance profilometry, is independent of the annealing time at 1200-degrees-C. In the CZ samples instead it considerably decreases with time. Secondary ion mass spectrometry analysis in CZ samples have revealed the presence of a multipeak structure around the projected range region for both Al and 0 signals. In FZ the structure is just detectable. The results imply that the Al-0 complex formation is enhanced by the presence of oxygen but that it is catalyzed by the damage created during the implant. The carrier profiles coincide in both CZ and FZ diffused substrates by predeposition of Al from a solid source, i.e., in damage-free samples.