Defect formation and annealing behavior of Si implanted by high-energy 166Er ions

Abstract

Si crystals were implanted at room temperature with 2.0 MeV 166 Er + ion doses of 5×10 12, 1×10 14, 5×10 14, 1×10 15 and 2.5×10 15 ions/ cm 2 . Conventional furnace thermal annealings were carried out in the temperature range from 600°C to 1150°C. The radiation damage and annealing behavior were investigated using the Rutherford backscattering spectrometry and channeling (RBS/C) technique. Doses above 5×10 14 ions/ cm 2 were found to produce amorphous layers. The experimental results show that the annealing behavior of 2.0 MeV Er + implanted into silicon is strongly influenced by the implantation dose and annealing temperature. For the samples with dose of 5×10 14 ions/ cm 2 and more, an abnormal annealing behavior was found and a qualitative explanation has been given. For the sample implanted with dose of 2.5×10 15 ions/ cm 2 , a substantial Er outdiffusion has been investigated. Er outdiffusion increases with annealing temperature, Er depth distribution changes from an initially unimodal Gaussian form to a bimodal distribution with a build up of Er concentration near the surface.