The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 02, 2011
Filed:
Jun. 24, 2008
Mitsutoshi Kawamoto, Otsu, JP;
Shinsuke Tani, Takatsuki, JP;
Mitsutoshi Kawamoto, Otsu, JP;
Shinsuke Tani, Takatsuki, JP;
Murata Manufacturing Co., Ltd., Kyoto-fu, JP;
Abstract
A semiconductor ceramic has a mixing molar ratio m between the Sr site and the Ti site satisfying the relationship 1.000≦m<1.020, a donor element in an amount of 0.8 to 2.0 moles relative to 100 moles of the Ti element dissolved in the Sr site to form a solid solution, the donor element having a higher valency than the Sr element, a transition metal element, such as Mn, incorporated in an amount of 0.3 to 1.0 mole relative to 100 moles of the Ti element so as to be segregated in grain boundaries, and an average grain size of crystal grains is 1.0 μm or less. A component body in which semiconductor ceramic layers are stacked and internal electrodesare embedded provides a SrTiO-based grain boundary insulation type semiconductor ceramic having a high apparent relative dielectric constant of 5,000 or more even if the average grain size of crystal grains is decreased to 1 μm or less, and a semiconductor ceramic capacitor in which it is possible to achieve both a reduction in layer thickness and improvement in dielectric characteristics by using the SrTiO-based grain boundary insulation type semiconductor ceramic.