XAFS Investigation of Nanoparticle Formation in ⁶⁴ Zn ⁺ Ion Implanted and Thermo Oxidized Si

The single crystal CZ n-Si(100) substrates with electron concentration no = 5 × 1016 cm−3 were implanted by 64Zn+ ions with dose of 5 × 1016 cm−2 and energy of 50 keV. During implantation the ion beam current density was less than 0.5 μA/cm2 to avoid the substrate magnetically heating. After implantation, the plates were subjected to isochronous for one hour heat treatment in oxygen atmosphere at temperatures from 400 up to 1000oC with a step of 100oC. Zn K-edge EXAFS spectra were measured in fluorescent mode. Si(111) channel-cut monochromator was used for energy scanning; energy resolution ΔE/E = 2 × 10–4. According to Zn K-edge EXAFS data, all Zn implanted in Si at 900oC is fully oxidized: an absolute maximum of EXAFS Fourier transform at R ~ 1.6 Å corresponds to Zn–O distance. Based on XANES data, we suggest an interaction between implanted Zn atoms and Si support.