Surface roughness with nanometer-scale Ag particles generated by ion implantation

Surfaces of SiO2, Si3N4, Ta2O5 and glass were implanted with Ag+ ions. Studies using X-ray diffraction and atomic force microscopy show that the surface morphology is dominated by metallic silver features consisting of regularly shaped, mostly spherical, Ag particles spanning a size range from some nm to some 100 nm in diameter. The particle size, distribution, shape and density are shown to be controlled by the process parameters ion dose, dose rate and ion energy. Adjusting the energy of the incident ions results in various degrees of submerging into the substrate including exposed Ag features anchored onto the surface or buried Ag particles overcoated by a thin layer of the matrix material. The substrate material differs by its ability to stabilize the dispersion and block the Ag movement. Ta2O5 and glass substrates provide more homogenously dispersed Ag particles, much smaller and more regularly shaped than SiO2 and Si3N4 substrate systems. The potential application of such materials is to surface enhanced analytical techniques.