Composition and electronic structure of hidden nanoscale phases and layers of BaSi-=SUB=-2-=/SUB=- formed in the near-surface of Si

Abstract

For the first time, nanoscale phases and layers of BaSi2 were obtained by implantation of Ba+ ions with an energy of E0=20-30 keV in the surface layer of Si(111). In particular, it is shown that at a dose of D~1015 cm-2 nanophases with a band gap Eg~0.85 eV are formed, and at D~1017 cm-2 a BaSi2 nanolayer with Eg=0.67 eV. The composition and structure of the barium disilicide nanostructure were investigated by light absorption spectroscopy by Auger electron spectroscopy, and the X-ray surface morphology was studied by scanning electron microscopy. The optimal modes of ion implantation and annealing for obtaining nanoscale phases and layers of BaSi2 in the near-surface region of Si have been established. Using the method of light absorption spectroscopy, the band gap and the degree of coverage of the layer with BaSi2 nanophases were estimated. It has been shown that at a dose of D≥6·1016 cm-2 the nanolayer of BaSi2. Keywords: ion implantation, nanostructure, nanophase, annealing, barium disilicide, Auger electrons, degree of coverage.