Ion beam studies of Ge diffusion in Al 2 O 3

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Beam interactions with materials and atoms, 2012-02, Vol.272, p.74-77
• Main Authors: Barbagiovanni, E.G., Dedyulin, S.N., Simpson, P.J., Goncharova, L.V.
• Format: Article
• Language: English
• Subjects: Aluminum; Annealing; Beam interactions; Binding energy; Crystal defects; Desorption; Diffusion; formula omitted; Germanium; Nano-Crystals; X-ray photoelectron spectroscopy
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2011.01.036

Rutherford backscattering spectroscopy (RBS) has been used in combination with X-ray photoemission spectroscopy (XPS) to investigate Ge diffusion in Al 2 O 3 (0001) samples. Ge was implanted in c-plane α - Al 2 O 3 (0001) at 80 keV to a fluence of 1 × 10 16 cm - 2 at room temperature followed by thermal annealing in the 30–180 min range at 1200 °C in a N 2 environment. RBS results indicate that implantation-induced damage does not fully amorphize the substrate, while incurred defects are partially annealed after 1 h accompanied by Ge phase crystallization. XPS data confirms the existence of GeO 2 and GeO. There is a decrease in the Ge content compared to the as-implanted sample, attributed to GeO desorption, which is evident after 30 min and by 180 min 15% of the original Ge concentration remains. Integrated intensity of the Ge peak in aligned geometry is much lower compared to random geometry with a bimodal distribution of Ge evident in both spectra indicating Ge substitutional incorporation and the formation of a distinct Ge layer. XPS data shows a peak thought to be associated with the distinct Ge layer at ≈1216.5 eV, which is a lower binding energy than a Ge reference peak. The lower binding energy is thought to result from a net positive electron density in the substrate due to excess Al atoms in the peak defect-region.