Solid phase epitaxial growth of Dy-germanide films on Ge(0 0 1) substrates

Abstract

Dy thin films are grown on Ge(0 0 1) substrates by molecular beam deposition at room temperature. Subsequently, the Dy film is annealed at different temperatures for the growth of a Dy-germanide film. Structural, morphological and electrical properties of the Dy-germanide film are investigated by in situ reflection high-energy electron diffraction, and ex situ X-ray diffraction, atomic force microscopy and resistivity measurements. Reflection high-energy electron diffraction patterns and X-ray diffraction spectra show that the room temperature growth of the Dy film is disordered and there is a transition at a temperature of 300–330 °C from a disordered to an epitaxial growth of a Dy-germanide film by solid phase epitaxy. The high quality Dy 3Ge 5 film crystalline structure is formed and identified as an orthorhombic phase with smooth surface in the annealing temperature range of 330–550 °C. But at a temperature of 600 °C, the smooth surface of the Dy 3Ge 5 film changes to a rough surface with a lot of pits due to the reactions further.