Modification of barium titanate powders for capacitor applications

Abstract

As the miniaturization with increasing functionalities and acceleration of the clock speed of electronic devices continues, the desired characteristics and processabilty of the starting powder become more of an issue. For barium titanate (BT) for capacitors, one is the chemical stability of BT in water as the slip medium. Aqueous processing of BT is considered to replace the current state-of-the-art non-aqueous processing technology for the obvious reasons. The second issue is the size of the particles. A greater volume efficiency of passive components, and multi-layer ceramic capacitors (MLCCs) in particular, points toward thinner dielectric layers or embedded design. All of these require a smaller particle size of the raw BT powders with closely-controlled particle morphology, high dispersibility, and better dielectric properties. This paper presents some of our recent results in meeting the demands for current and future capacitor applications of BT powders. One is in the property of the starting powder and the other is in processing of the powder for producing MLCCs. The third issue is the crystal phase of the BT particles at room temperature with the size in the range of nanometre. The fourth issue is the impurities incorporated in the BT crystal lattice. One notable impurity is hydroxyls. These issues are considered to meet the demands by modifying BT for current and future capacitor applications.