Preferred orientations in nano-gold/silica/silicon interfaces

Abstract

Gold in contact with silicon substrates Si(1 0 0), Si(1 1 1), and SiO 2 is studied by thermal evaporation and annealing in N 2 using the modified sphere-plate technique. The final orientation distribution of crystalline Au films grown on Si substrate systems that incorporate a native amorphous oxide layer of silica and Au on amorphous silica (SiO 2 glass) substrates is influenced by preferred orientations and twinning. Experimental evidence suggests that the orientation of Au{1 1 1} close packed planes (multiply twinned) was found to be of low-energy as the annealing temperature was increased to 530 °C and 920 °C. Additional orientations were observed for Au{1 0 0} on Si(1 0 0) substrates and Au{1 0 0}, {1 1 0}, and {3 1 1} on SiO 2 substrates. After annealing at 920 °C the size distribution of the gold particles was determined to be within the range of 20–800 nm while the morphology of gold surface appears spherical to faceted in character. These results show similarities to recent findings for smaller nano-size 1D particles, islands and thin Au films on silicon annealed over lower temperature ranges.