Samples were implanted with B through a surface oxide, and then annealed. This led to an enhanced B diffusivity. This enhancement was suppressed during an initial incubation period. An activation energy of 2eV was associated with the enhanced diffusion (table 29), and this suggested that excess Si interstitials were involved. However, the process which led to the onset of enhanced diffusion was associated with an apparent activation energy of 3.7eV. The use of 2-step annealing reduced the latter value to 2.6eV. This was the activation energy for the diffusion of interstitial O. Transmission electron microscopy revealed that the coalescence of dislocations, as well as the growth of faulted loops, occurred rapidly after the incubation period. Precipitates which were situated along small dislocation loops were observed after the incubation period. It was suggested that O precipitation, with emission of Si interstitials, predominated upon annealing beyond the incubation period and was responsible for the enhanced B diffusion. It was proposed that the enhanced diffusion was initially incubated by the trapping of O at dislocations. The true onset of enhanced diffusion occurred when the dislocations were saturated and the oxide precipitation began at dislocations.

Role of Recoil Implanted Oxygen in Determining Boron Diffusion in Silicon. D.Fan, R.J.Jaccodine: Journal of Applied Physics, 1990, 67[10], 6135-40