The Future Development Trends Of Ceramic Capacitors

In order to make the size of the product smaller and the resonance frequency higher, MLCC manufacturers will face two challenges: on the one hand, they require a higher dielectric constant of the ceramic material, exceeding 10000; on the other hand, they require a thinner ceramic film (<10) while maintaining a high dielectric constant (>100) μ m) . When high resonant frequency and low series resistance are required, this type of MLCC is increasingly used in coupling, bypass, or filtering circuits. In order to optimize electrical performance, it is necessary to determine the effects of materials, design, and assembly methods.

Japan has achieved a leading position in this field. Murata Productions claims that they have developed 1 μ The size of F's capacitor is only 3.2mmX1.6mm, which is half of that of traditional capacitors. The production method is to use barium titanate powder with extremely fine particles, which makes the medium used thinner. Of course, the capacitance of a given size capacitor increases, and according to the company's records and production, it only starts with a monthly production of 500%.

In high-temperature resistant electronic systems used in engine control systems and aerospace exploration equipment, stable high-temperature resistant (300-600 ° C) multilayer ceramic capacitors are required as sensors. The materials used should be compatible with high-temperature semiconductors (SiC, diamond). The University of Pennsylvania in the United States is seeking Class I dielectric ceramics BaZrO3, Ba (Mg1/3Ta2/3) O3, PMN, and PZT with paraelectric and relaxation properties, high Tc ferroelectric La2Ti2O, Sr2Nb2O, and antiferroelectric Biz (Mg4/Nb2/3) O7. Controlling the purity, processing methods, and defects of the optimal composition can optimize the material, resulting in an increase in resistivity and breakdown strength at 600C.

With the introduction of increasingly strict environmental regulations, it is necessary to develop environmentally friendly low firing ceramic materials: they do not produce volatile substances such as PbO and do not need to be processed in solvent based adhesive systems. TAM Ceramic Company in the United States is researching the use of CuO based baking aids to develop low sintering Z5U and Y5V dielectric ceramics. According to the required dielectric constant (up to 10000 or above), the ceramic material contains various ratios of BaCuO2: WO3 or BaCuO2: MoO3. After roasting at 1100C for 2 hours, the density can exceed 95% of the theoretical value. WOz causes a decrease in Curie temperature, while MoO3 has no effect.

For charge storage capacitors used in devices such as VLSI DRAM (Very Large Scale Integrated Circuit Dynamic Random Access Memory) and low inductance decoupling capacitors used in high-speed switching VLSI devices to control simultaneous noise, low dielectric material leakage current, high breakdown strength, and high dielectric constant are required. For 256 bit DRAM, the charge storage density is required to be within the range of (20-115) pC/cm2, leakage current density is required to be within the range of (30-360) mA/cm2, and dielectric thickness is required to be within (0 01~0.2) μ Within the range of m. The preliminary study of Arizona State University in the United States shows that the non ferroelectric perovskite type produced by the sol gel method.