Implantation-induced nonequilibrium reaction between Zn ions of 60 keV and SiO2 target

Silica glass (SiO2) was implanted with 60 keV Zn+ ions to a fluence of 1.0x10(17) ions/cm(2), and the chemical states were investigated along the depth in as-implanted state by x-ray excited Auger electron spectroscopy and x-ray photoelectron spectroscopy. The metallic Zn and Zn2SiO4 phases were found to have, respectively, formed in the shallow and deep regions of the SiO2, whereas thermodynamics predicts the Zn phase only. Oxygen atoms in SiO2 are preferentially displaced to the deeper region because of the lighter mass. The excess oxygen in the deep region and athermal energy from the implantation drive the formation of Zn2SiO4. (c) 2007 American Institute of Physics.