Ferroelectric-Antiferroelectric Capacitor Stack for High Capacitance Density
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Solution Overview
Problem
Semiconductor devices face challenges in achieving high integration densities due to the need for capacitors with sufficient electrostatic capacitance in limited areas, which is proportional to the surface area of electrodes and dielectric constant, and inversely proportional to the equivalent oxide thickness of the dielectric layer.
Innovation Solution
A semiconductor device with a capacitor structure that alternately stacks first dielectric layers made of ferroelectric material and second dielectric layers made of anti-ferroelectric material between the bottom and top electrodes, adjusting the thicknesses of these layers to increase electrostatic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the surface area of the electrode is increased to achieve higher electrostatic capacitance, then the electrostatic capacitance is improved, but the integration density is worsened due to the limited area available
Solution Approach 1:
The patent applies composite materials by stacking multiple dielectric layers with different dielectric constants (high-k and low-k materials) to create an effective dielectric constant that is higher than individual materials. This composite structure increases the electrostatic capacitance without requiring additional area, as the effective dielectric constant directly multiplies the capacitance value in the parallel plate capacitor formula.
Solution Approach 2:
The patent changes the dielectric parameter by using materials with different dielectric constants and adjusting their thickness ratios. By optimizing the combination of high-k and low-k dielectric materials, the effective dielectric constant is tuned to achieve the desired capacitance density, allowing higher capacitance within the same footprint area.
2Reliability
If the dielectric constant of the dielectric layer is increased to achieve higher electrostatic capacitance, then the electrostatic capacitance is improved, but the manufacturing complexity is worsened
Solution Approach 1:
The patent segments the dielectric layer into multiple sub-layers with different dielectric constants (high-k and low-k materials). This segmentation allows each layer to be optimized independently for its specific function, while the overall structure achieves the desired effective dielectric constant. The segmented approach simplifies manufacturing by using standard deposition techniques for each material layer rather than requiring complex processing for a single high-k material.
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 configuration enhances the electric and reliability characteristics of semiconductor devices by increasing electrostatic capacitance, addressing the challenge of high integration density requirements.
Implementation Method 1
The first dielectric layers include a ferroelectric material
Implementation Method 2
The second dielectric layers include an anti-ferroelectric material
Implementation Method 3
The electrostatic capacitance of the capacitor is proportional to a surface area of an electrode and a dielectric constant of a dielectric layer
Data Source
AI summary
A semiconductor device includes a capacitor structure. The capacitor structure includes a bottom electrode, a dielectric layer, and a top electrode that are sequentially stacked in a first direction. The dielectric layer includes first dielectric layers and second dielectric layers interposed between the bottom electrode and the top electrode and are that are alternately stacked in the first direction. The first dielectric layers include a ferroelectric material, and the second dielectric layers include an anti-ferroelectric material. A lowermost second dielectric layer is interposed between a lowermost first dielectric layer and the bottom electrode, and an uppermost second dielectric layer is interposed between an uppermost first dielectric layer and the top electrode.