Threading dislocation evolution in mega-electron-volt phosphorus implanted silicon

The effect of dose and energy on postannealing defect formation for high energy ~mega-electron-volt! phosphorus implanted silicon has been studied using etch pit studies and transmission electron microscopy ~TEM!. Previous work has shown that after annealing there is a strong dependence of dislocation density threading to the surface on the implanted phosphorus dose and energy. A superlinear increase in threading dislocation density ~TDD! with implant energy between 180 and 1500 keV is observed for a dose of 1310 cm. In addition as a function of ion fluence, there is a maximum in the threading dislocation density at a dose of 1310 cm followed by a rapid decrease in TDD. Both the superlinear increase in TDD with increasing energy and the rapid decrease with increasing dose have been further investigated by TEM. A TEM study of these higher doses revealed formation of a strong bimodal loop distribution with small loops averaging ,1000 Å and large loops averaging around 1 mm in size. Over the dose range of 1310 cm to 5310 cm, the superlinear decrease in TDD from 1310 cm to ,1310 cm coincides with the superlinear increase in small dislocation loops from below 1310 cm to above 1 310 cm. It is suggested that the homogeneous nucleation theory can explain many of the results. However, the chemical presence of phosphorus appears to also play an important role in the formation of the small dislocation loops and possibly threading dislocations. © 2001 American Institute of Physics. @DOI: 10.1063/1.1351865#