Low temperature dependence of resistivity in obliquely sputter-deposited gold thin films

Abstract

We report on the electrical resistivity at low temperature of Au thin films 400 nm thick deposited by DC magnetron sputtering using oblique angle deposition (OAD). The deposition angle α is gradually and systematically changed from 0° to 80°. A tilted and voided columnar structure is produced for deposition angles higher than 60°, whereas the lowest angles lead to a dense and compact structure with no clear cross-section morphology. Resistivity vs. temperature measurements reveal a typical metallic-like behavior in the range 7–300 K whatever the deposition angle. The latter gives rise to a significant increase of residual resistivity and temperature coefficient of resistance, and again for the most grazing angles, i.e., α > 60°. The Bloch-Grüneisen model is assumed for understanding the evolution of electron-phonon interactions as a function of the deposition angle. This enhanced resistivity is connected to the structural defects and the porous architecture especially emphasized for glancing angles, and the strengthening of the electron-phonon coupling for high deposition angles.