The behavior of vacancy-type defects and displaced Si atoms in (100) samples, due to self-ion implantation, was investigated by means of variable-energy positron annihilation spectroscopy and Rutherford back-scattering spectroscopy and channelling. It was found that the recovery of the defects depended strongly upon the morphology of the implanted region. The di-vacancies that were produced by a Si+ fluence of 2 x 1014/cm2, which was less than the critical dose for amorphization, aggregated into large vacancy clusters during annealing at 300C. These vacancy clusters diffused towards the surface at temperatures above 600C, and annealed out at about 800C. A specimen that was implanted to 2 x 1015/cm2, where complete amorphization took place in the damaged region, exhibited a different annealing behavior. In a first stage (at about 600C), the amorphous zone transformed into crystalline material via solid-phase epitaxial growth; although large vacancy clusters still remained. These agglomerates continued to grow during a second annealing stage which occurred at about 700C. Annealing at 900C was required in order to eliminate these vacancy-type defects.

M.Fujinami, A.Tsuge, K.Tanaka: Journal of Applied Physics, 1996, 79[12], 9017-21