Anomalous enhanced tail B diffusion in directly bonded samples of heavily- or lightly-doped material was observed after annealing at 1000 to 1200C. As in the case of the enhanced diffusion commonly observed in B-implanted material during damage annealing, the enhanced diffusion in directly bonded samples was suggested to be due to mobile interstitial B species. In heavily-doped Czochralski-type material, interstitial B species could be produced via elastic interactions between excess Si interstitials and substitutional B atoms during solidification. The enhanced diffusivity, as deduced by comparing the present results with those obtained for B-implanted specimens, could be described by:

D(cm2/s) = 3 x 10-4exp[-2.1(eV)/kT]

An Anomalous Enhanced Tail Diffusion of Boron in Directly Bonded Samples of Heavily and Lightly Doped Silicon. W.Wijaranakula: Japanese Journal of Applied Physics 1, 1993, 32[9A], 3872-8