Chemical solution deposited silver tantalate niobate, Ag x (Ta0.5Nb0.5)O3−y , thin films on (111)Pt/Ti/SiO2/(100)Si substrates

Abstract

Silver tantalate niobate films are candidates for temperature stable microwave dielectrics. In this work, a chemical solution deposition synthesis method was developed for Ag x (Ta0.5Nb0.5)O3−y films on Pt-coated Si substrates. Stable solutions with a range of silver stoichiometries were prepared using 2-methoxyethanol and pyridine as solvents, from AgNO3 and Nb and Ta ethoxide precursors. It was extremely difficult to prepare phase-pure perovskite films of Ag(Ta0.5Nb0.5)O3 on Pt-coated Si subtrates; instead a mixture of perovskite and natrotantite phases was identified. Such mixed phase films had dielectric constant ɛ r and dielectric loss tanδ values ranging from 200±20 to 270±25 and 0.006±0.002 to 0.002±0.001 at 100 kHz, respectively, depending on the firing temperature. For Ag2(Ta0.5Nb0.5)4O11, Ag0.8(Ta0.5Nb0.5)O2.9, Ag0.85(Ta0.5Nb0.5)O2.925 and Ag0.9(Ta0.5Nb0.5)O2.95 films, mainly the natrotantite phase was observed. The ɛ r values of these films were between 70±10 and 130±15 with tan δ values of 0.008±0.002 at 100 kHz.