Damage accumulation in neon implanted silicon

Abstract

Damage accumulation in neon-implanted silicon with fluences ranging from 5x1014 to 5x1016 Ne cm-² has been studied in detail. As-implanted and annealed samples were investigated by Rutherford backscattering spectrometry under channeling conditions and by transmission electron microscopy in order to quantify and characterize the lattice damage. Wavelength dispersive spectrometry was used to obtain the relative neon content stored in the matrix. Implantation at room temperature leads to the amorphization of the silicon while a high density of nanosized bubbles is observed all along the ion distribution, forming a uniform and continuous layer for implantation temperatures higher than 250°C. Clusters of interstitial defects are also present in the deeper part of the layer corresponding to the end of range of ions. After annealing, the samples implanted at temperatures below 250°C present a polycrystalline structure with blisters at the surface while in the other samples coarsening of bubbles occurs and nanocavities are formed together with extended defects identified as {311} defects. The results are discussed in comparison to the case of helium-implanted silicon and in the light of radiation-enhanced diffusion.