Composite MLCCs with X7R characteristics

摘要

The low-sintering composite multilayer ceramic capacitors (CMLCCs) having K-value in excess of 7200 with X7R characteristics (-55/spl sim/+125/spl deg/C, /spl plusmn/15%) have been successfully developed. The CMLCCs incorporate four PMN-PNN-PT or PMN-PT based ceramics with different Curie temperatures as the principal components. The green tapes and inner electrodes are stacked during green printing according to a certain order and cofired to prepare this kind of multi-material multilayer chip component. According to the parallel-connecting model of capacitance, the dielectric constant (K) of CMLCC can be approximately determined by the proportion of four dielectrics with different Curie temperatures. The small difference between the calculative curve and testing curve can be explained by the mutual diffusion among different dielectrics via the inner electrode. The research results show that it is feasible to produce chip components with high performance by cofiring multi-phases materials.