Low firing monolithic ceramic capacitor with high dielectric constant

Abstract

The ceramic body of a monolithic ceramic capacitor consists of a granular barium titanate phase and a relatively low temperature melting intergranular phase. The body is capable of exhibiting a very high dielectric constant, e.g., over 5000, a Curie temperature of near 25.degree. C., and may be fired to maturity at 1150.degree. C. or lower and contain low cost buried electrodes. These properties obtain from a narrow range of compositions for which charge balance and large/small cation stoichiometry in the total formulation are found to be very critical. Cd, Zn, Cu, Li and Na are found to enter the grains as large acceptor cations on Ba sites and may be charge compensated by the small donor cations of charge +5, Bi, Sb, Nb and Ta or by the small donor cations of charge +6, W and Mo, on the Ti sites. At least 0.3 mole percent of glass-former cations are desirable for establishing a low melting flux during sintering but more than 2.2 mole percent glass-formers tends to reduce the dielectric constant.

Dependencies are inferred from the claim text.