Improvement of the sintering and dielectric characteristics of surface barrier layer capacitors by CuO addition

Calcined (Ba0.8Sr0.2) (Ti0.9Zr0.1)O-3 (BSTZ) with added CuO is used as an improved material with which to fabricate surface (or reduction-reoxidation) barrier layer capacitors (BLCs). The CuO-containing BSTZ appears to have less temperature, frequency, and bias dependence of the dielectric characteristics and a lower sintering temperature (1325 degrees C versus 1390 degrees C) as compared to BSTZ without CuO. For the same annealing conditions, for example, annealing at 1000 degrees C for 60 min, the effective dielectric constant of CuO-added BSTZ (sintering at 1325 degrees C) is larger than that of BSTZ without CuO (sintering at 1390 degrees C). The addition of MnO accelerates the annealing process, causing the semiconductive ceramics to reoxidize into dielectric materials within 30 min. CuO addition can lead to an important competitive merit for BSTZ dielectrics, especially in the fabrication of surface BLCs with an easily controllable fabrication process to give stable dielectric characteristics.