Al‐Based Precipitate Evolution during High Temperature Annealing of Al Implanted in Si

Al-based precipitate evolution for 80 keV Al ions implanted in Si has been investigated. Precipitates are formed during high temperature annealings of 1 [times] 10[sup 15]/cm[sup 2] implanted samples. They are located at two depths where Al concentration peaks are detected. Al atoms are gettered into the extended defects present in the crystal and/or precipitate when their concentration is higher than the solid solubility value at the annealing temperature. Increasing annealing time, precipitates dissolve out and only a small fraction of atoms diffuses into the sample, meanwhile the greater part evaporates from the sample. At 1 [times] 10[sup 13]/cm[sup 2] dose Al concentration is below the solid solubility limit. The secondary defects are not detected and the dopant profile does not display anomalous peaks. Moreover, all the implanted Al is electrically active and remains in the sample during the first instant of annealing. At higher annealing times it diffuses out of the sample reducing the residual dose.