On the Dynamic Annealing Mechanism in P+-Implanted Silicon

TEM and RBS analysis are made of (100) Si specimens implanted with 100 keV P+ ions at a dose rate of 60 μA/cm2, in order to investigate the mechanism for dynamic annealing. The activation energy for regrowth during ion irradiation is found to be 0.31 eV, much lower than the value for thermal epitaxy of (100)Si. The comparison with samples implanted at room temperature and annealed with an e-beam of the same power density shows that in the temperature range 230 to 620 °C and for the irradiation times used in the experiments (t ≦ 7.6 s), the pure contribution o beam heating to the regrowth process is negligible. This result supports the hypothesis that the mechanism responsible for dynamic annealing during high flux ion implantation is the recombination at the α/c interface of point defects produced by the elastic collision of energetic ions with the target atoms. From the regrowth data it can be deduced that, in this kind of annealing regime, the recrystallization rates in 〈100〉 and 〈111〉 directions are of the same order of magnitude.