Copper enhanced (111) texture in silver thin films on amorphous SiO2

Abstract

Small amounts (5at.%) of copper were added to silver thin films to improve adhesion and minimize agglomeration on SiO2 layers. Resistivity measurements from the Ag(Cu) films showed that small Cu additions do not significantly increase the resistivity compared to pure Ag. Texture evolution and surface morphology of Ag and Ag(Cu) thin films on SiO2 were also investigated using x-ray diffraction (XRD) techniques and atomic force microscopy. Normalized (111) θ-2θ XRD intensities increased from 91.6% to 96.8% upon addition of Cu, likely due to enhanced adatom diffusion resulting from the Cu addition. XRD pole figure analysis revealed differences in texture evolution between the Ag and Ag(Cu) thin films. Since high adatom surface diffusion of Cu promotes preferred grain growth of the Ag matrix, Ag(Cu) thin films showed enhanced (111) texture compared to Ag thin films. Glancing angle XRD results confirmed the evolution of (111) texture in the Ag and Ag(Cu) thin films. In the case of Ag, (111) texture was enhanced mainly by recrystallization of disordered regions during annealing. In addition to recrystallization, (111) texture enhancement in Ag(Cu) was attributed to consumption of grains with other non-(111) crystallographic orientations.