Aqueous-processed aluminum oxide phosphate (AlPO) dielectric films were studied to determine how water desorbs and absorbs on heating and cooling, respectively. In-situ Fourier transform infrared spectroscopy showed a distinct, reversible mono- to bidentate phosphate structural change associated with water loss and uptake. Temperature programmed desorption measurements on a 1-μm thick AlPO film revealed water sorption was inhibited by an aqueous-processed HfO2 capping film only 11-nm thick. The HfO2 capping film prevents water resorption, thereby preserving the exceptional performance of AlPO as a thin-film dielectric.
Perkins, C. K.; Mansergh, R. H.; Park, D.-H.; Nanayakkara, C. E.; Ramos, J. C.; Decker, S. R.; Huang, Y.; Chabal, Y. J.; Keszler, D. A. Aqueous process to limit hydration of thin-film inorganic oxides. Solid State Sci. 2016, 61, 106–110 http://dx.doi.org/10.1016/j.solidstatesciences.2016.09.012