T. Bertrams et al., TUNNELING THROUGH AN EPITAXIAL OXIDE FILM - AL2O3 ON NIAL(110), Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 12(3), 1994, pp. 2122-2124
By controlled oxidation of a clean NiAl(110) surface an epitaxial thin
layer of Al2O3 may be grown. The oxide layer shows a sharp low-energy
electron diffraction pattern of two domains of nearly rectangular uni
t cells. A stable tunneling current was obtained for a wide range of s
ample bias voltages U (from a few mV up to nearly 10 V). For U in the
mV range the images essentially contain contributions of the interface
layer, which can be measured with atomic resolution. For large U (e.g
., 4 V) the electronic states of the oxide film contributed additional
ly to the substrate electrons, which allows an accurate analysis of th
e growth mode of the oxide film.