Use of Sol-Gels in the Application of Ceramic Oxide Thin Films

摘要

Single components sols were characterized and used to make thin films on silicon wafers. The empirical equation, d = (2000 log( mu ) + 350)(w)/sup -0.5/, was obtained, which adequately describes the thickness of the sintered films, independent of the ceramic oxide, solvent, concentration, sol age, and reaction conditions. The single component sols were used to make binary oxide sols - barium titanate, lithium niobate, and lithium tantalate. A barium solution can be added to the titania sol to produce a barium titanate compound of the desired composition, including Ba sub 2 Ti sub 9 O sub 20 and BaTi sub 5 O sub 11 . Mixing a lithium solution into either a niobia or a tantala sol yielded the desired compound along with a heavy metal oxide (either lithium niobate with niobium oxide or lithium tantalate with tantalum oxide). However, dissolving lithium methoxide with the ethoxide of niobium or tantalum in ethanol, prior to hyrolysis, did produce the desired binary oxide (lithium niobate or lithium tantalate) without any uncombined metal oxide. By altering the stoichiometric ratios of the constituent cations, different compounds were produced for dielectric characterization with an AC bridge circuit. In the case of the barium titanates, these calculated constants ranged from a high of 26.0 for TiO sub 2 , to a low of 11.9 for BaTi sub 5 O sub 11 . The range for lithium tantalate was from a high of 21.6 for a stoichimetry of Li sub 7 TaO sub 6 , to a low at 8.4 for LiTaO sub 3 . Lithium niobate ranged from a high at 21.1 for Nb sub 2 O sub 5 , to a low at 8.9 for Nb sub 2 O sub 5 at a stoichimetry of Li sub 2 Nb sub 32 O sub 81 . (ERA citation 12:043625)