CHARACTERIZATION OF DEFECTS IN SELF-ION IMPLANTED SI USING POSITRON-ANNIHILATION SPECTROSCOPY AND RUTHERFORD BACKSCATTERING SPECTROSCOPY

The behavior of vacancy-type defects and displaced Si atoms in Si(100) caused by self-ion implantation has been investigated by variable-ene rgy positron annihilation spectroscopy and Rutherford backscattering s pectroscopy/channeling. It is found that the recovery process of the d efects strongly depends on the morphology of the implanted region. The divacancies produced by an implantation of 2x10(14)Si(+). cm(-2), whi ch is less than the critical value required for amorphization, aggrega te into large vacancy clusters by annealing at 300 degrees C. These va cancy clusters diffuse towards the surface at temperatures above 600 d egrees C and anneal out at around 800 degrees C. The specimen implante d with 2x10(15)Si(+). cm(-2), in which a complete amorphization takes place in the damaged region, shows a different annealing characteristi c. In the first stage (similar to 600 degrees C), the amorphous zone i s transformed into crystalline material by solid phase epitaxial growt h, although large vacancy clusters still remain. These agglomerate clu sters continue to grow in a second annealing stage which takes place a t around 700 degrees C. Annealing at 900 degrees C is required to elim inate these vacancy-type defects. (C) 1996 American Institute of Physi cs.