It was shown that many of the phenomena related to the formation of so-called tails in the low-concentration region of ion-implanted impurity distribution were due to the anomalous diffusion of non-equilibrium impurity interstitials. These phenomena included boron implantation in pre-amorphized silicon, a “hot” implantation of indium ions, annealing of ion-implanted layers etc. In particular, to verify this microscopic mechanism, a simulation of boron redistribution during low-temperature annealing of ion-implanted layers was carried out under different conditions of transient enhanced diffusion suppression. Due to the good agreement with the experimental data, the values of the average migration length of non-equilibrium impurity interstitials were obtained. It was shown that for boron implanted into a silicon layer pre-amorphized by germanium ions the average migration length of impurity interstitials at the annealing temperature of 800C could be reduced from 11nm to approximately 6nm due to additional implantation of nitrogen. The further shortening of the average migration length was observed if the processing temperature was reduced to 750C. It was also found that for implantation of BF2 ions into silicon crystal, the value of the average migration length of boron interstitials was equal to 7.2nm for thermal treatment at 800C.

Modeling of the Transient Interstitial Diffusion of Implanted Atoms during Low-Temperature Annealing of Silicon Substrates. O.I.Velichko, A.P.Kavaliova: Physica B, 2012, 407[12], 2176-84