B implants of 1 keV, 1 x 10(15) at. cm(-2) into 125-nm-wide, free-standing Si nanostructures have been characterized using scanning spreading resistance microscopy following a 0 s, 1050 degreesC anneal in N-2. A curved diffusion front has been observed. B in the center of the ridge diffuses further than at the sides. A similar effect has been observed in SUPREM-IV simulations. It is attributed to a reduction in transient enhanced diffusion close to the vertical surfaces due to recombination of ion-implantation-induced excess Si self-interstitials. (C) 2005 American Vacuum Society.