Experimental evidences for two paths in the dissolution process of B clusters in crystalline Si

We show that B clusters, produced by self-interstitial interaction with substitutional B in crystalline Si, dissolve under annealing according to two distinct paths with very different characteristic times. The two regimes generally coexist, but while the faster dissolution path is predominant for clusters formed at low B concentration (1x10(19) B/cm(3)), the slower one is characteristic of clusters formed above the solubility limit and dominates the dissolution process at high B concentration (2x10(20) B/cm(3)). The activation energies of both processes are characterized and discussed. It is showed that the faster path can be connected to mobile B direct emission from small clusters, while the slower path is demonstrated not to be self-interstitial limited and it is probably related to a more complex cluster dissolution process.