Thermal evolution of extended defects in implanted Si: impact on dopant diffusion

摘要

Annealing of ion-implanted Si leads to the formation of various extrinsic defects which affect dopant diffusion. In this paper, we describe the mechanisms by which, small clusters evolve into {1 1 3} defects, then transform into dislocation loops of either faulted or perfect type, upon annealing, the former being the only one to survive for long annealing times. This approach assumes that these defects exchange Si interstitial atoms upon annealing and that the reduction of the formation energies of the defects due either to their size increase or to a change in their structural characteristics is the driving force for their thermal evolution. Since the supersaturation of silicon interstitial atoms in dynamical equilibrium with these defects is an exponential function of these formation energies, a realistic description of the time-evolution of this supersaturation in the defect region and in the whole wafer responsible for transient-enhanced diffusion of boron, can be obtained.