Radiation-enhanced diffusion in ion-implanted glasses and glass/metal couples

Ion implantation causes alkali migration to the surface in alkali silicate glasses. Rutherford backscattering spectrometry was used to follow this depletion. Room temperature implantations of 5 x 1016 250 keV Xe/cm2 in 12M20.88SiO2 (M = Li, Na, K, Rb, Cs) removes approximately equal numbers (within a factor of 2) of alkali from the glass. Low temperature (77K) implants significantly reduce the alkali loss. These results imply a radiation-enhanced diffusion mechanism in which the alkali interchanges with the products of the collision cascade, with the kinetics being limited by the radiation damage components. The results for mixed-alkali glasses ((12-x)M2O.xCs20.88Si02) give further evidence for this process. In glass/metal couples, radiation enhanced diffusion allows the interchange of glass network components with deposited metals. Rutherford backscattering spectrometry was used to follow the interchange of silicate and phosphate glass components with metal ions near the heavy-ion implanted interface between glass substrate and metal (Al,Zr) films