High Density Capacitor Using Solid Electrolyte and Trench Structure
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Solution Overview
Problem
Conventional capacitors face challenges in achieving high capacitance density on a small area due to limitations in dielectric thickness and material properties, while electrochemical capacitors suffer from high internal resistance and instability at high frequencies, making them unsuitable for integration on silicon substrates.
Innovation Solution
A solid-state electrochemical capacitor with a non-crystalline lithium intercalating cathode and anode, using a solid electrolyte that allows lithium ion migration, and diffusion barrier layers to prevent lithium diffusion, enabling high capacitance density and stability at low temperatures, suitable for integration on silicon substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional parallel plate capacitor structure is used, then manufacturing is simple, but capacitance density cannot be increased further due to dielectric thickness limitations
Solution Approach 1:
The patent transitions from conventional 2D parallel plate capacitors to 3D trench capacitor structures. The trench capacitor embeds the capacitor within a vertical trench in the substrate, allowing the electrode area to extend into the third dimension (depth), thereby significantly increasing capacitance density without proportionally increasing the surface footprint or manufacturing complexity.
Solution Approach 2:
The patent implements a stacked capacitor configuration where multiple capacitor structures are vertically stacked within the same trench or adjacent trenches. This nesting approach allows multiple capacitor units to occupy the same lateral footprint by stacking them in the vertical direction, effectively increasing capacitance density while maintaining a compact form factor and manageable structural complexity.
2Quantity of substance
If electrochemical capacitor with liquid electrolyte is used, then energy density increases significantly, but stability at high temperatures decreases and integration on chip becomes blocked
Solution Approach 1:
The patent changes the physical state parameter of the electrolyte from liquid to solid. By using a solid electrolyte instead of a liquid electrolyte, the capacitor maintains high energy density while achieving improved thermal stability and enabling integration on silicon chips. This parameter change eliminates the fundamental limitations of liquid electrolytes regarding temperature stability and miniaturization.
3Quantity of substance
If electrochemical capacitor with liquid electrolyte is used, then capacitance density increases, but internal resistance increases limiting energy release
Solution Approach 1:
The patent changes the electrolyte state from liquid to solid, which fundamentally alters the ion transport mechanism. The solid electrolyte enables faster ion conduction compared to liquid electrolytes in the trench capacitor structure, thereby reducing internal resistance and improving the power delivery capability while maintaining high capacitance density.
Solution Approach 2:
The patent optimizes the local properties of the electrode materials and electrolyte interface to enhance ion transport efficiency. By carefully selecting and engineering the materials at the electrode-electrolyte interfaces, the patent reduces interfacial resistance and improves overall ion conduction, enabling faster energy release while maintaining high capacitance density.
4Quantity of substance
If dielectric thickness is decreased to increase capacitance density, then capacitance density increases, but leakage current increases and breakdown voltage decreases
Solution Approach 1:
The patent employs composite material structures in the trench capacitor, combining different dielectric materials and electrode materials to achieve optimal performance. The composite structure allows for thinner effective dielectric layers while maintaining high breakdown voltage and low leakage current through the synergistic properties of the constituent materials, thereby increasing capacitance density without sacrificing 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 solution achieves significantly higher capacitance density and stability at high temperatures, allowing for integration on silicon substrates and improved performance in high-frequency applications, with reduced leakage and enhanced reliability compared to conventional capacitors.
Implementation Method 1
a solid state electrolyte allowing migration of metal ions between the anode and the cathode
Implementation Method 2
Electrochemical capacitors store the energy by moving ions in electric double layers or store electrical energy as chemical energy by means of redox reactions
Data Source
AI summary
A high density capacitor 12, a method of manufacturing it, and applications of it are described. The capacitor 12 is an electrochemical capacitor using a metal ion accepting cathode 22 and a metal ion accepting anode 26 and a amorphous solid electrolyte 24 between. The cathode and anode may be of amorphous lithium ion intercalating material such as suitable transition metal oxides with multiple oxidation states.