To obtain the subject composition having negative resistance- temperature characteristics and improved in reliability through raising its sintering density, by incorporating the main component consisting of a lanthanum-cobalt-based oxide with oxide(s) of specific subcomponent element(s) and boron oxide.
The main component consisting of a lanthanum-cobalt-based oxide shown by the formula LaxCoO3 (0.60≤(x)≤0.99) is incorporated with, as subcomponents, 0.001-10 mol.% (in terms of element) of at least one oxide of element selected from the group consisting of Si, Zr, Hf, Ta, Sn, Sb, W, Mo, Te, Ce, Nb, Mn, Th, and P and 0.0001-5 mol.% (in terms of B) of boron oxide to obtain the objective semiconductor ceramic composition having negative resistance-temperature characteristics. The other objective semiconductor ceramic device having negative resistance-temperature characteristics, high in sintering density, while suppressing the variance in both room temperature resistivity and the B-constant at 140°C, is obtained by prebaking, grinding, granulating, molding, and baking the above composition to produce a semiconductor ceramic, which is then provided with electrodes.
NIIMI HIDEAKI
URAHARA RYOICHI
SAKABE YUKIO
