M. Anastasescu, M. Gartner, A.Ghita, L.Predoana, L Todan, M. Zaharescu, C. Vasiliu, C. Grigorescu, Loss of phosphorous in silica-phosphate sol-gel films, J.Sol-Gel Sci. Technol., 40 (2006) 325

Title: Loss of phosphorous in silica-phosphate sol-gel films

Abstract: Phosphosilicate films with 90%SiO2-10%P2O5 molar composition, derived from tetraethoxysilane as SiO2 precursor and triethylphosphate, triethylphosphite or phosphoric acid as P2O5 precursors were prepared using the sol-gel method. The films were deposited on glass and ITO coated glass supports. The influence of the type of P2O5 precursor, type of substrate and of the thermal treatment (200, 300 and 500 degrees C) on their structure and properties was studied. By spectroellipsometric and XPS measurements the high vaporization of the phosphorous during the densification of the films by thermal treatment was noticed when alkoxide were used, underlying that the mentioned precursors are not recommended for thin phosphosilicate films preparation. The phosphoric acid that forms chemical bond with silica network during the sol-gel process lead to better incorporation of P in the silica network as compared to the P-alkoxides

Key words: phosphosilicate films; sol-gel; ellipsometry; phosphorous loss