| 摘要 |
A semiconductor ceramic comprising a donor element within the range of 0.8 to 2.0 mol relative to 100 mol of Ti element contained as a solid solution with crystal grains, a first acceptor element in an amount less than the amount of the donor element is contained as a solid solution with the crystal grains, a second acceptor element within the range of 0.3 to 1.0 mol relative to 100 mol of a Ti element is present in crystal grain boundaries, and the average grain size of the crystal grains is 1.0 mum or less. A monolithic semiconductor ceramic capacitor is obtained by using this semiconductor ceramic. To form the semiconductor ceramic, in a first firing treatment to conduct reduction firing, a cooling treatment is conducted while the oxygen partial pressure at the time of starting the cooling is set at 1.0x10<SUP>4 </SUP>times or more the oxygen partial pressure in the firing process. In this manner, a SrTiO<SUB>3 </SUB>based grain boundary insulation type semiconductor ceramic having a large apparent relative dielectric constant ∈r<SUB>APP </SUB>of 5,000 or more and a large resistivity log rho (rho:Omega.cm) of 10 or more even when crystal grains are made fine to have an average grain size of 1.0 mum or less, a monolithic semiconductor ceramic capacitor including the semiconductor ceramic, and methods for manufacturing them are realized.
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