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The electrical properties of dopants in Si are of primary importance for the realization of electronic devices. Indium represents a promising p-type dopant whose electrical properties are improved by codoping with C. From theoretical studies In and C are expected to pair in the Si matrix in order to lower the strain energy. In this contribution we provide the first direct experimental determination of the sites of In and In–C complexes in Si. [ABSTRACT FROM AUTHOR]

The activation process induced by excimer laser annealing (ELA) has been investigated in 10 keV B-implanted samples. It is found that for energy densities inducing melt depths of the order or larger of the implanted region the junction depth is controlled by the melt depth, with activation approaching 100% and box-shaped carrier density distributions with abrupt junction profile. For energy densities inducing a melting shallower than the implanted region, two different activation mechanisms have been identified: the first occurring in the molten region and leading to complete B activation; the second occurring in the region immediately below the molten zone and leading to thermal activation of B, induced by the heat wave propagating into the Si wafer. This last process is characterized by an activation energy of 5 eV and is not accompanied by B diffusion. As a consequence, a deep tail of active B is produced, preventing the possibility to form abrupt and ultrashallow junctions. These results suggest that for the formation of ultrashallow junctions it is essential to combine ELA with ultralow energy ion implantation. [ABSTRACT FROM AUTHOR]