Thin Film Capacitor Electrode Structure for High Capacitance
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Solution Overview
Problem
Existing thin film capacitors face challenges in achieving high capacitance within a reduced size and thickness, as materials with high dielectric constants often lead to degradation of breakdown voltage and increased leakage current due to reactions between internal electrode layers and dielectric layers at high temperatures.
Innovation Solution
A thin film capacitor structure is developed with a first internal electrode layer made of a high-conductivity material with a low melting point and a second internal electrode layer made of a low-conductivity material with a high melting point, where the second internal electrode layer coats the upper and lower surfaces of the first internal electrode layer, preventing direct contact and reaction with the dielectric layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a material with a high dielectric constant is used to increase capacitance, then the capacitance increases, but the breakdown voltage degrades and leakage current increases due to reactions between internal electrode layers and dielectric layers at high temperatures
Solution Approach 1:
A low-conductivity material layer is introduced as an intermediary between the high-conductivity internal electrode layer and the dielectric layer. This intermediary layer prevents direct contact and chemical reactions between the electrode and dielectric materials during high-temperature processing, thereby maintaining breakdown voltage reliability while allowing the use of high-dielectric-constant materials for increased capacitance.
Solution Approach 2:
The internal electrode structure uses a composite material configuration: a high-conductivity material (such as copper or aluminum) is combined with a low-conductivity protective material (such as titanium nitride or tungsten). This composite structure provides both the electrical conductivity needed for capacitor function and the thermal/chemical stability required to prevent degradation during high-temperature processing.
2Quantity of substance
If a material with a high dielectric constant is used to increase capacitance, then the capacitance increases, but leakage current increases due to reactions between internal electrode layers and dielectric layers
Solution Approach 1:
The low-conductivity material layer serves as a protective intermediary that physically separates the internal electrode from the dielectric layer, preventing harmful chemical reactions that would otherwise increase leakage current. This allows the capacitor to use high-dielectric-constant materials without suffering from the associated leakage problems.
3Loss of energy
If the internal electrode layer is made of high-conductivity material with low melting point, then ESR characteristics improve, but material spreading and reaction with dielectric layer occurs at high temperatures
Solution Approach 1:
The internal electrode is constructed as a composite structure where a high-conductivity, low-melting-point material (providing low ESR) is combined with a low-conductivity, high-melting-point protective material. This composite configuration allows the capacitor to achieve low energy loss through the high-conductivity layer while the protective layer prevents material spreading and maintains compositional stability during high-temperature processing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This structure enhances capacitance while maintaining improved ESR characteristics by preventing material spreading and reaction between the internal electrode layers and dielectric layers, even at high temperatures, thus achieving a thin film capacitor with high capacitance and reduced ESR.
Implementation Method 1
a second internal electrode layer made of a low-conductivity material with a high melting point, where the second internal electrode layer coats the upper and lower surfaces of the first internal electrode layer, preventing direct contact and reaction with the dielectric layer
Data Source
AI summary
A thin film capacitor includes a body including a dielectric layer, a first internal electrode layer and a second internal electrode layer, a melting point of a material included in the first internal electrode layer being lower than a melting point of a material included in the second internal electrode layer, and a first external electrode and a second external electrode disposed on an upper surface of the body, the second internal electrode layer being disposed on an upper surface of the first internal electrode layer and a lower surface of the first internal electrode layer opposing the upper surface of the first internal electrode layer.