One-step, low-temperature sintering of SrTiO3 based grain boundary barrier layer capacitor materials

A novel technique was developed to fabricate SrTiO₃-based GBBL (grain-boundary barrier layer) capacitor materials. The main feature of this technique is one-step, low-temperature (1100-1200°C) sintering of the material, which is doped with a sintering aid composed of Li₂O and SiO₂ , in a reducing atmosphere. The main dielectric properties of the materials obtained by this technique are effective dielectric constant ∈_eff>5×10⁴, dielectric loss tan δ<5.0%, volume resistivity ρ>10⁹ Ω-cm, temperature coefficient of ∈_eff<10% (-25-+85°C). The effects of dopant composition, sintering temperature, atmosphere, and Ti/Sr ratio on the sinterability and dielectric property of the capacitor materials are discussed. The mechanism underlying the role of sintering in the formation of semiconducting grains and insulating grain boundaries is examined, using the results of compositional microanalyses and microstructural analyses