Thin-Film Capacitor Interlayer for Low Leakage at Small Scale
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Solution Overview
Problem
Existing capacitors face challenges in maintaining capacitance and reducing leakage current as they shrink in size, with traditional methods like increasing electrode area or reducing dielectric thickness reaching their limits, and ternary oxide dielectrics with small bandgaps lead to high leakage currents.
Innovation Solution
Incorporating an interlayer with a novel structure, such as an anionized or neutral layer, between the electrode and dielectric layers, which has the same crystal structure but different composition, to enhance the Schottky barrier height and reduce leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of the capacitor is reduced for miniaturization, then the capacitance decreases and leakage current increases, but the device size is reduced
Solution Approach 1:
An interlayer is introduced between the electrode and dielectric layers to act as an intermediary that suppresses leakage current. This interlayer has the same perovskite crystal structure as the adjacent layers but different composition, creating a Schottky barrier that blocks charge carrier movement while maintaining the miniaturized capacitor structure
Solution Approach 2:
The composition of the interlayer is specifically designed with different cation ratios compared to the electrode and dielectric layers. By changing the compositional parameters while maintaining crystal structure similarity, a Schottky barrier is formed that suppresses leakage current in miniaturized capacitors
2Reliability
If ternary oxide dielectric material is used to increase capacitance, then the capacitance increases, but the leakage current increases due to small bandgap
Solution Approach 1:
The interlayer serves as a mediator between the high-capacitance ternary oxide dielectric and the electrode. Despite the dielectric's small bandgap providing high capacitance, the interlayer forms a Schottky barrier that prevents the associated high leakage current from reaching the electrode
Solution Approach 2:
The interlayer introduces local quality differentiation at the electrode-dielectric interface. While the dielectric maintains its high-capacitance properties throughout, the interlayer locally modifies the interface properties to suppress leakage current through Schottky barrier formation
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 interlayer design increases the Schottky barrier height, effectively reducing leakage current and maintaining capacitance in capacitors, even as they are miniaturized.
Implementation Method 1
A Schottky barrier is the difference between the work function (Φ) of an electrode and the electron affinity (χ) of the dielectric film (e.g., of a dielectric). For example, when the electrode and the dielectric come into contact, the Fermi levels thereof become equal, and thus, an energy barrier called the Schottky barrier is formed at the interface between the electrode and the dielectric, suppressing the movement of charges, and thus improving the leakage current.
Data Source
AI summary
Provided are a capacitor, an electronic device including the same, and a method of manufacturing the same, the capacitor including a first thin-film electrode layer; a second thin-film electrode layer; a dielectric layer between the first thin-film electrode layer and the second thin-film electrode layer; and an interlayer between the dielectric and at least one of the first thin-film electrode layer or the second thin-film electrode layer, the interlayer including a same crystal structure type as and a different composition from at least one of the first thin film electrode layer, the second thin film electrode layer, or the dielectric layer, the interlayer including at least one of a anionized layer or a neutral layer.