Silicon hyperdoping using selenium and manganese ion implantation and pulsed laser annealing

Abstract

The effect of pulsed laser annealing (PLA) on the structure and optical properties of Mn-, Seand (Mn+Se)implanted silicon layers was studied. 95 keV Mn+ and 200 keV Se+ ions were implanted separately and together into p-type Si wafers up to the fluence 1 · 1016 cm–2 at room temperature. Then, the samples were irradiated in the ambient air with a single 2 J/cm2 ruby laser pulse. The detailed redistribution of Mn and Se atoms in the implanted layers during PLA was examined using Rutherford backscattering spectroscopy in random and channeling configuration. It was found that a notable percentage of implanted manganese atoms diffuses to the silicon surface, while the Se concentration depth profile broadens in both directions after PLA. Mn co-implantation enhances the Se diffusion to the surface, which leads to a Se decrease in crystalline silicon, but it does improve the crystal structure of the implanted silicon layer due to the increase of diffusion velocity. In contrast to the Mn-implanted sample, Se-implanted and (Mn+Se)-co-implanted samples after PLA exhibit strong optical absorption in the infrared range. The observed band at 0.6 eV is associated with electronic transitions from the intermediate band to the lowest energy levels of the conduction band.