Formation, evolution and annihilation of interstitial clusters in ion implanted Si

Formation, thermal evolution and annealing kinetics of self-interstitial cl usters in ion implanted Si have been investigated. Deep level transient spe ctroscopy measurements performed on epitaxial and Czochralski Si samples im planted with Si ions at energies of 145 keV or 1.2 MeV reveal that these cl usters are formed for fluences above 10(12)/cm(2) and annealing temperature s higher than 550 degrees C. Interstitial clusters introduce seven well def ined levels in the Si band gap at E-v+0.33 eV, E-v+0.52 eV, E-c-0.58 eV, E- c-0.50 eV, E-c-0.37 eV, E-c-0.29 eV and E-c-0.14 eV. Analysis of the anneal ing kinetics at temperatures in the range 550-700 degrees C reveal that the clusters undergo Ostwald ripening and anneal out with a characteristic dis sociation energy of similar to 2.3 eV for a Si fluence of Ix 10(12)/cm(2). Futhermore, their annealing temperature increases with implantation fluence . These results indicate that small interstitial clusters act as the source of interstitial supersaturation that drive transient enhanced dopant diffu sion in the absence of extended defects. (C) 1999 Published by Elsevier Sci ence B.V. All rights reserved.