Phase formation and texture of thin nickel germanides on Ge(001) and Ge(111)Phase formation and texture of thin nickel germanides on Ge(001) and Ge(111)
Faculty of Sciences. Physics
Electron microscopy for materials research (EMAT)
2016New York, N.Y. :American Institute of Physics, 2016
Journal of applied physics / American Institute of Physics. - New York, N.Y., 1937, currens
119(2016):13, 12 p.
University of Antwerp
We studied the solid-phase reaction between a thin Nifilm and a single crystal Ge(001) or Ge(111) substrate during a ramp anneal. The phase formation sequence was determined using in situX-ray diffraction and in situRutherford backscattering spectrometry (RBS), while the nature and the texture of the phases were studied using X-ray pole figures and transmission electron microscopy. The phase sequence is characterized by the formation of a single transient phase before NiGe forms as the final and stable phase. X-ray pole figures were used to unambiguously identify the transient phase as the ϵ-phase, a non-stoichiometric Ni-rich germanide with a hexagonal crystal structure that can exist for Ge concentrations between 34% and 48% and which forms with a different epitaxial texture on both substrate orientations. The complementary information gained from both RBS and X-ray pole figure measurements revealed a simultaneous growth of both the ϵ-phase and NiGe over a small temperature window on both substrate orientations.