Multilayer Ceramic Capacitor Interface Layers for Higher Capacitance
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Solution Overview
Problem
Existing multilayer ceramic capacitors face challenges in increasing capacitance while maintaining dielectric layer thickness and grain size uniformity, leading to irregularities and reduced lifespan due to internal electrode layer thickness irregularities and dielectric loss.
Innovation Solution
A multilayer ceramic capacitor is developed using a common ceramic material comprising 70-90% barium titanate and 3-25% rare earth oxides (lanthanum, samarium, and neodymium oxides) with 0.3-1.0% nickel oxide, where the grain sizes of high dielectric layers and dielectric layers satisfy specific ratios, forming high dielectric layers on interfaces to enhance capacitance and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the dielectric layers and electrode layers are made thin to increase capacitance, then the capacitance increases, but the internal electrode layers become irregular or partially broken, increasing dielectric loss and decreasing product lifespan
Solution Approach 1:
The patent changes the chemical composition parameters of the ceramic material by adding rare earth elements (lanthanum, samarium, neodymium) in specific amounts (0.1-5 wt% each) to BaTiO3 base material. This compositional parameter change enables the formation of high dielectric layers with controlled grain sizes (50-500 nm) that maintain structural integrity even when dielectric layers are made thin, thus resolving the contradiction between increased capacitance and maintained reliability
Solution Approach 2:
The patent creates a composite ceramic material system combining BaTiO3 with multiple rare earth oxides (La2O3, Sm2O3, Nd2O3) and other additives (SiO2, Al2O3, TiO2). This composite material structure forms high dielectric layers at the interface between dielectric and electrode layers, providing both high capacitance and structural stability, thereby preventing electrode layer irregularities and breakdown while maintaining thin layer dimensions
2Quantity of substance
If the number of layers is increased to increase capacitance, then the capacitance increases, but the manufacturing precision and uniformity of layer thickness become more difficult to control
Solution Approach 1:
The patent modifies the sintering process parameters (temperature, time, atmosphere) and ceramic material composition to control grain growth during sintering. By adding rare earth elements and controlling sintering conditions, the grain sizes of high dielectric layers are maintained within 50-500 nm range, ensuring uniform layer properties even when the number of layers is increased, thus maintaining manufacturing precision while achieving higher capacitance
3Quantity of substance
If the grain sizes of dielectric layers are controlled to improve capacitance, then the capacitance increases, but it becomes very difficult to improve the capacitance further using conventional methods
Solution Approach 1:
The patent introduces a composite ceramic system with rare earth element additives (La2O3, Sm2O3, Nd2O3) combined with BaTiO3 base material and other oxides (SiO2, Al2O3, TiO2). This composite formulation enables control of grain size and dielectric properties through material composition rather than complex process control, making it easier to manufacture high-capacitance capacitors with consistent performance
Solution Approach 2:
The patent changes the chemical composition parameters of the ceramic material by incorporating rare earth elements in optimized amounts, which fundamentally alters the sintering behavior and grain growth characteristics. This parameter change enables easier control of grain size and dielectric properties compared to conventional single-phase BaTiO3 systems, reducing manufacturing difficulty while improving capacitance
Data Source
AI summary
Provided is a multilayer ceramic capacitor having dielectric layers and internal electrode layers laminated alternately on one another. Each internal electrode layer comprises a common ceramic material containing 3 to 25% by weight of rare earth elements, and through the rare earth elements, high dielectric layers are formed on the interfaces between the dielectric layers and the internal electrode layers.