| 摘要 |
PURPOSE:To obtain an excellent grain boundary dielectric layer type semiconductor porcelain substance to be used for a semiconductor porcelain capacitor, improving its dielectric constant and insulation resistivity, by diffusing a composition containing one or more kinds of bismuth oxides and sodium based metallic compounds, sodium based metallic oxides, each of which is in a specified amount, into the grain boundary of the semiconductor porcelain. CONSTITUTION:A dielectric layer in the grain boundary of a semiconductor porcelain is formed by diffusing a composition containing a Bi2O3 of 20-90mol% and one or more kinds of sodium based metallic compounds and sodium based metallic oxides of 80-10mol% into said grain boundary. For example, a disk- like element assembly is obtained by pressure molding a raw material prepared by adding an Nb2O5 and an MnO2 of 0.1-2mol%, respectively, to an SrTiO3, a principal component, and then is fired for 4-10 hours at 1400-1540 deg.C in a reducing atmosphere of hydrogen (1-15%) and nitrogen (99-85%) to obtain a sintered body. The sintered body is painted with said composition acting as a diffusing substance and fired for 1-2 hours at 1000-1350 deg.C in the air. Then, a silver paste is provided on both sides of the sintered body and baked at 800 deg.C to form electrodes for the semiconductor porcelain capacitor. |
