Capacitor dielectric with internal barrier layers and a method for its production

Claim 1

A capacitor dielectric with internal barrier layers comprising: a polycrystalline ceramic body made of material of a perovskite structure on the basis of barium titanate of the general formula (Ba 1-x M x II )O·z(Ti 1-y M y IV )O 2 in which M II is selected from the group consisting of Ca, Sr, Pb and Mg and M IV is selected from the group consisting of Zr and Sn and z assumes the values 1.005 to 1.05; at least two different doping substances one of which causing predominantly n conduction inside the crystallites and the other causing predominantly p conduction in a surface layer of the crystallites; a proportion of the doping substance causing the n conduction being 1.5 to 2.5 times greater than the maximum doping quantity and a proportion of the substance causing the p conduction amounting to 0.01 to 0.15% by weight; the capacitor dielectric comprising two crystalline main phases of different composition which are present in roughly the same quantities and of which the first is substituted barium titanate of the formula (Ba 1-x1 M.sub. x.sbsb.1 II )O·z(Ti 1-y .sbsb.1 M y .sbsb.1 IV )O 2 provided with doping substances causing n conduction and p conduction and the second crystalline main phase is substituted barium titanate of the formula (Ba 1-x .sbsb.2 M x .sbsb.2 II )O·z(Ti 1-y .sbsb.2 M y .sbsb.2 IV )O 2 provided with doping substances causing n conduction and p conduction x 1 , y 1 , x 2 , and y 2 assuming a value between 0 and 1.