Energetics and diffusivity of indium-related defects in silicon

We present a theoretical investigation on In-related defects in silicon, aimed at understanding In interactions with native defects, vacancy (V) and self-interstitial (I), and at determining the energy parameters needed to efficiently simulate and interpret the experimental profiles. Ab initio total-energy calculations within density- functional theory and in the generalized gradient approximation are performed in order to investigate equilibrium geometries and formation energies of substitutional In, In-I, and In-V complexes. We determine the migration energies of I- and V-mediated diffusion mechanisms, discussing the location of saddle points along the minimum-energy paths. Moreover, we report anomalous characteristics of the interactions between In and V with respect to other p-like dopants. The ab initio energetics are then implemented into a continuum model for In diffusion. This allows the accurate simulations of experimental secondary-ion-mass-spectroscopy profiles of implanted and annealed samples, at various process conditions (i.e., annealing temperature, implant energy).