Dissolution kinetics of boron-interstitial clusters in silicon

Abstract

In this work, we have investigated the stoichiometry of boron-interstitial clusters (BICs) produced in a molecular-beam-epitaxy-grown B box by Si implantation and annealing, and their dissolution during further prolonged annealing cycles. Low-concentration B delta doping was used to quantitatively monitor the interstitial (I) flux. A stoichiometric ratio of about 1.2 between I and B was found for the BICs formed at 815 °C. The BIC dissolution kinetics was investigated by analyzing the concentration profiles at different times and temperatures (in the range 815–950 °C) with a simulation code able to deconvolve the processes of B diffusion and B release from clusters. We found that the main mechanism for cluster dissolution is the release of interstitial boron atoms, with a thermal activation energy of 3.2±0.4 eV. These data are discussed and compared with existing literature data.