Neutral boron-interstitial clusters in crystalline silicon

The formation of B clusters inside ultrashallow junctions is one of limiting factors in the miniaturization process of electronic devices. The assembling of these clusters corresponds to a reduction of the electrical activity of the doping process. Exploiting hierarchically different simulation techniques, we investigate structural and electronic properties of small B clusters inside a crystalline Si matrix. Density-functional-theory-tight-binding molecular dynamics simulations are carried,out as scouts selecting the candidates to be analyzed in depth via ab initio calculations. The latter provide insights into the electronic properties of the B clusters, identifying the fingerprints of interstitialcy and chemical composition in their densities of states.