On the shrinkage of rod-shaped defects in boron-ion-implanted silicon

Three different types of rod-shaped defects formed during postimplantation annealing of boron-implanted silicon are distinguished in annealing experiments carried out on transmission electron microscope specimens. It is shown that rod-shaped defects can be boron precipitates, Frank dipoles, or perfect a/2 <110≳ dipoles. All shrink from the ends only during annealing. The temperature dependence of shrinkage rate for the first type was determined by measuring dL/dt at three different temperatures for a given isolated defect. Boron diffusion appeared to be the rate-determining process. The second type, Frank dipoles, were often observed to unfault, transforming into the third type during annealing. At the time of unfaulting the newly formed perfect dipole was always observed to rotate on its glide cylinder to near edge orientation.