Ferroelectric-Antiferroelectric Capacitor Stack for High Capacitance
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Solution Overview
Problem
As integration densities of semiconductor devices increase, there is a need for capacitors with high electrostatic capacitance in limited areas, which existing designs struggle to achieve effectively due to the limitations in surface area, dielectric constant, and equivalent oxide thickness of traditional dielectric layers.
Innovation Solution
A semiconductor device with a capacitor structure that includes a dielectric layer comprising a ferroelectric material and an anti-ferroelectric material, along with a first impurity, which aligns dipoles when an electric field is applied, increasing the dielectric constant and electrostatic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional dielectric layers are used in capacitor structures, then the device structure remains simple, but the electrostatic capacitance is insufficient for high integration density requirements
Solution Approach 1:
The patent employs a composite dielectric layer structure consisting of a first dielectric layer with ferroelectric material and a second dielectric layer with anti-ferroelectric material. This composite structure achieves high electrostatic capacitance by combining materials with different dielectric properties, where the ferroelectric layer provides high dielectric constant and the anti-ferroelectric layer enhances stability and prevents leakage, thereby resolving the contradiction between increasing capacitance and maintaining structural simplicity.
Solution Approach 2:
The patent utilizes the phase transition properties of ferroelectric and anti-ferroelectric materials to dynamically change dielectric parameters. By applying electric fields, the dipoles in the ferroelectric layer align to increase dielectric constant, while the anti-ferroelectric layer provides counteracting stability. This parameter change approach enables high capacitance states when needed while maintaining overall structural integrity and preventing breakdown.
2Quantity of substance
If the surface area of electrodes is increased to achieve higher capacitance, then electrostatic capacitance improves, but the available area in limited semiconductor device space is consumed
Solution Approach 1:
Instead of increasing electrode surface area, the patent changes the dielectric parameter (dielectric constant) by utilizing ferroelectric and anti-ferroelectric materials with high and tunable dielectric constants. The ferroelectric material's dipole alignment under electric fields significantly increases the effective dielectric constant, thereby increasing capacitance without requiring additional area, thus resolving the area-capacitance trade-off.
Solution Approach 2:
The composite dielectric structure combines ferroelectric and anti-ferroelectric materials to achieve high effective dielectric constant in a compact configuration. This allows the capacitor to achieve high capacitance values within the same footprint area, effectively resolving the contradiction between capacitance enhancement and area conservation for high integration density.
3Quantity of substance
If the dielectric constant of the dielectric layer is increased to enhance capacitance, then electrostatic capacitance improves, but the equivalent oxide thickness increases reducing capacitance
Solution Approach 1:
The patent uses a composite structure where the ferroelectric layer provides high dielectric constant to increase capacitance, while the anti-ferroelectric layer is positioned to provide electrical stability and prevent leakage paths. This composite approach allows achieving high capacitance through increased dielectric constant without proportionally increasing equivalent oxide thickness, as the anti-ferroelectric layer compensates for thickness increases by maintaining electrical integrity.
Solution Approach 2:
The patent exploits the electric field-induced phase transition in ferroelectric materials to dynamically change the dielectric constant parameter. When electric field is applied, the ferroelectric layer transitions to a high dielectric constant state, increasing capacitance. The anti-ferroelectric layer provides a stabilizing effect that prevents uncontrolled thickness increases, thereby resolving the contradiction between dielectric constant enhancement and equivalent oxide thickness control.
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 proposed solution significantly enhances electrostatic capacitance by aligning dipoles in the dielectric layer, effectively addressing the challenge of increasing capacitance in densely integrated semiconductor devices.
Implementation Method 1
The first dielectric layer includes a ferroelectric material... aligning dipoles when an electric field is applied, increasing the dielectric constant and electrostatic capacitance
Implementation Method 2
the second dielectric layer includes an anti-ferroelectric material
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 stacked in a first direction. The dielectric layer includes a first dielectric layer, a second dielectric layer stacked on the first dielectric layer in the first direction, and a first impurity provided in the first dielectric layer. The first dielectric layer includes a ferroelectric material, and the second dielectric layer includes an anti-ferroelectric material.