Oyoshi Keiji

Formation of phosphosilicate glass layers in glasses by ion implantation

Abstract P+ ion implantation was performed in silica, Na2OSiO2, and CaONa2OSiO2 glasses. The chemical interaction of implanted P was evaluated by X-ray photoelectron spectroscopy. In the silica glass, half of the implanted P reacted with O. Most of the implanted P was oxidized by a subsequent O+ implantation. Enhancement of Na gettering in the phosphosilicate glass layer was observed in the additionally O+ implanted silica as evaluated by secondary ion mass spectrometry. In Na2OSiO2 and Na2OCaOSiO2 glasses, the ratio of oxidized to unoxidized P depends on the glass composition and on the dose of P+ ions. In Na2OSiO2 glasses, the fraction of oxidized P increases with the Na2O/SiO2 ratio. The substitution of CaO suppresses the oxidation of implanted P when compared with Na2OSiO2 glasses. We discuss the dependence of phosphorus oxidation on the glass composition from a viewpoint of surface-alkali-depletion by ion implantation.