Dependence of fiber texture on composition in metal-insulator Au–SiO2 composite thin films

Abstract

The authors show that the evolution of metal fiber texture in phase segregated metal-insulator composite thin films depends strongly on the composition. Using x-ray diffraction pole figures, they measured the strength of the Au (111) fiber texture as a function of composition in the phase segregated Au–SiO2 system, codeposited by magnetron sputtering at room temperature. They find that for very low SiO2 volume fractions, less than 5%, Au has low resistivity and a strong (111) fiber texture similar to that of pure Au. For higher SiO2 volume fractions, up to 30%, the strength of the Au fiber texture decreases more rapidly with increasing SiO2 volume fraction than can be attributed to the decreasing Au volume fraction. They propose that the rapid decrease in Au (111) fiber texture strength is consistent with Zener pinning of Au grains by second-phase SiO2 particles. For SiO2 volume fractions greater than 30%, the Au fiber texture is lost as the Au phase becomes disrupted, the films become insulating, and the microstructure changes to randomly oriented Au islands within an insulating matrix of SiO2.