Patent ID: 7583493

Claim:
A monolithic semiconductor ceramic capacitor having a varistor function, comprising a monolithic sintered body and external electrodes located on end surfaces of the monolithic sintered body, the monolithic sintered body comprising a plurality of semiconductor ceramic layers and a plurality of internal electrodes each of which is arranged between adjacent semiconductor ceramic layers, the semiconductor ceramic layers made of a semiconductor ceramic which is of a boundary insulative layer-type comprising SrTiO 3 , each of the external electrodes being electrically connected to different ones of the internal electrodes, wherein the semiconductor ceramic has a Sr site, a Ti site, crystal grains and grain boundary layers and satisfies the inequality 1.000<m≦1.020 where m represents the molar ratio of the Sr site to the Ti site; the crystal grains having an average size of 1.0 μm or less and comprising a solid solution containing a donor element; the grain boundary layers containing an acceptor element in an amount greater than 0 mol and equal to or less than 0.5 mol per 100 mol of Ti.