HALBLEITERKERAMIKKONDENSATOR VON DEM LAMINIERTEN TYP MIT ZWISCHENKORNISOLATION UND VERFAHREN ZU SEINER HERSTELLUNG

摘要

This invention provides a laminated type grain boundary insulated semiconductor ceramic capacitor which usually works as a capacitor to absorb noise of low voltages or noise of high frequencies, which exhibits a varistor function when a high voltage such as a pulse or static electricity is applied thereto, and which is composed of SrTiO3 as a chief component that enables the ceramic capacitor material and the internal electrode material to be baked simultaneously, and a method of producing the same. The reason why the simultaneous baking of the materials has become possible is that the composition is such that components making a material semiconductor are added to SrTiO3 with excess of Ti, and that Mn and Si both convertible into MnO2 and SiO2 respectively in baking are added. Though a process of surface diffusion of metallic oxides has been conventionally performed, it can be omitted. By only re-oxidation, a grain boundary insulated semiconductor capacitor is easily obtained. According to the invention in which the molded product after lamination is calcined in advance in the air, the laminated ceramic capacitor with varistor function minimizes the occurrence of such problems as breakage of internal electrode, delamination, cracks, reduction of sintering density and heterogeneous structure in the sintered body, and exhibits markedly improved electric properties such as capacity, voltage nonlinearity index alpha and varistor voltage, and reliability. With respect to these two points, the invention has a notable advantage in material composition and process.