TRANSIENT PHOSPHORUS DIFFUSION BELOW THE AMORPHIZATION THRESHOLD

The transient-enhanced diffusion of phosphorus in silicon has been investigated for doses and energies below the threshold for amorphization of the substrate. Transient-enhanced diffusion occurs both for furnace and RTA annealing, and can increase the junction depth by 0.1-0.2-mu-m over that predicted by standard diffusion models. The magnitude of the transient is shown to depend on the implantation dose and energy, the anneal time and temperature, and the background doping level. A simple model of damage annealing is proposed which quantitatively describes the point defect enhancement of dopant diffusion and so allows each of these dependencies to be understood. In addition, these experiments provide a new means to characterize the diffusion and charge states of the point defects themselves.