Multilayer Ceramic Capacitor Dielectric for X6S Temperature Stability
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Solution Overview
Problem
Multilayer ceramic capacitors with rare earth elements added to BaTiO3 face instability in tetragonal structure, leading to reduced Curie temperature and deteriorated temperature properties, hindering high-temperature reliability and X6S temperature properties.
Innovation Solution
A multilayer electronic component with a dielectric layer comprising Ti, a first rare earth element (Dy and Tb) and a second rare earth element, where the mole ratio of Tb to Dy is greater than 1, and a valence variable acceptor element (Mn) is used, with specific mole ratios to enhance reliability and temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rare earth elements are added to BaTiO3 to improve reliability, then reliability is improved, but the tetragonal structure becomes unstable and Curie temperature decreases
Solution Approach 1:
The patent optimizes the concentration parameters of rare earth elements (Dy and Tb) in the dielectric layer, specifically setting their combined content to 0.01-0.1 wt% to maintain tetragonal structure stability while improving reliability. It also controls the ratio of Dy to Tb between 1:4 and 1:1, which fine-tunes the structural stability and electrical properties.
Solution Approach 2:
The patent creates a composite dielectric material by combining BaTiO3 with multiple rare earth elements (Dy and Tb) and Mn elements. This composite approach allows the synergistic effects of different elements to improve reliability while maintaining structural stability through complementary actions of the elements.
2Reliability
If rare earth elements replace Ba sites to reduce vacancy oxygen defects, then reliability is improved, but phase transition to cubic structure becomes easier and temperature properties deteriorate
Solution Approach 1:
The patent precisely controls the concentration of rare earth elements and Mn in the dielectric layer, setting rare earth element content to 0.01-0.1 wt% and Mn content to 0.1-1.0 wt%. This parameter optimization ensures sufficient reduction of vacancy oxygen defects for improved reliability while preventing excessive phase transition that would lower Curie temperature.
Solution Approach 2:
The patent introduces Mn elements at specific locations (grain boundaries and interfaces) in the dielectric layer to locally stabilize the tetragonal structure and pin domain walls. This local stabilization prevents unwanted phase transitions and maintains high Curie temperature while allowing rare earth elements to improve bulk reliability.
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
The component achieves improved X6S temperature properties and high-temperature reliability by stabilizing the dielectric structure and reducing capacitance aging, while maintaining miniaturization and high capacitance.
Implementation Method 1
when rare earth elements replace Ba sites, a tetragonal structure of BaTiO3 may become unstable and phase transition to the cubic structure becomes easier
Implementation Method 2
the dielectric layer includes Ti, a first subcomponent element including a rare earth element, and a second subcomponent element including Mn
Implementation Method 3
When rare earth elements are added to BaTiO3, Ba sites may be substituted and electrons may be generated, and vacancy oxygen defects may be effectively reduced
Implementation Method 4
Ba sites may be substituted and electrons may be generated
Implementation Method 5
a valence variable acceptor element (Mn) is used, with specific mole ratios to enhance reliability and temperature stability
Implementation Method 6
the dielectric layer includes Ti, a first subcomponent element including a rare earth element, and a second subcomponent element including Mn
Data Source
AI summary
A multilayer electronic component includes a dielectric layer and internal electrodes; wherein the dielectric layer includes a rare earth element, Mn, and Ti. The rare earth element includes a first rare earth element including Dy and Tb, and a second rare earth element including a rare earth element different from the first rare earth element. The number of moles of the rare earth element is defined as RE, the number of moles of Dy is defined as A1, the number of moles of Tb is defined as A2 based on 100 moles of Ti included in the dielectric layer, and 0.5 mol≤RE≤0.9 mol and 1<A2/A1 are satisfied. The number of moles of the second subcomponent element based on 100 moles of Ti included in the dielectric layer is 0.2 mole or more and 0.5 mole or less.