Thermal redistribution of Al implanted in Si: evidences for interactions with extended defects

Al was implanted at 180 keV to a dose of 4.5x 10(14) cm(-2). Various anneal s were performed in the temperature range (900-1100 degrees C), for times v arying from 15 min up to several hours. The SIMS measurements reveal anomal ous redistribution of the aluminium profiles. The bulk side of the profiles diffuses normally at a rate in agreement of the Al intrinsic diffusivity, but two peaks of apparently immobile atoms are formed near the surface. Cro ss observations by Transmission Electronic Microscopy (TEM) prove that ther e is no Al precipitation, and reveal the existence of two extended defects bands, the position of which is perfectly correlated with Al peaks. This st rongly suggests that these peaks are due to Al trapping on the extended def ects. First simulations also support this assumption. (C) 1999 Elsevier Sci ence B.V. All rights reserved.