Stacked Ferroelectric Capacitor Structure 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 capacitance in limited areas, while also reducing leakage current and maintaining effective operation within a specific voltage range.
Innovation Solution
A semiconductor device with a capacitor structure that includes a stack dielectric layer composed of zirconium oxide, hafnium-zirconium oxide, and another layer of zirconium oxide, each with both anti-ferroelectric and ferroelectric crystal phases, optimized to achieve maximum capacitance within a low voltage range of -0.9 V to 0.9 V.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If integration density is increased, then device functionality is improved, but capacitor leakage current increases
Solution Approach 1:
The patent employs a composite dielectric structure consisting of multiple layers with different materials (first dielectric layer, second dielectric layer with higher dielectric constant, third dielectric layer) to achieve high capacitance while maintaining low leakage current. This composite approach allows optimization of each layer's properties to balance capacitance and leakage characteristics.
Solution Approach 2:
The patent applies different dielectric materials with specific properties to different regions of the capacitor structure. The second dielectric layer with higher dielectric constant is positioned strategically to maximize capacitance contribution, while the first and third dielectric layers are configured to minimize leakage pathways, creating local quality variations that solve the contradiction.
2Quantity of substance
If dielectric layer thickness is reduced to increase capacitance, then capacitance is improved, but leakage current increases
Solution Approach 1:
The multi-layer dielectric structure allows the total effective thickness to be reduced for higher capacitance while each individual layer maintains sufficient thickness to control leakage. The second dielectric layer with higher dielectric constant compensates for the reduced thickness, achieving the desired capacitance without proportionally increasing leakage current.
Solution Approach 2:
The patent changes the dielectric constant parameter by introducing a second dielectric layer with higher dielectric constant than the first and third layers. This parameter change allows the structure to achieve high capacitance with reduced equivalent thickness while maintaining adequate leakage control through the composite architecture.
3Quantity of substance
If high dielectric constant material is used to increase capacitance, then capacitance is improved, but operation voltage range is restricted
Solution Approach 1:
The patent combines materials with different dielectric constants and electrical characteristics in a multi-layer configuration. The second dielectric layer with higher dielectric constant provides capacitance enhancement, while the first and third dielectric layers are selected to ensure stable operation across a wide voltage range from -1.0 V to +1.0 V, balancing capacitance and voltage adaptability.
Solution Approach 2:
Different dielectric materials are strategically positioned in the capacitor structure to perform different functions. The second dielectric layer with higher dielectric constant is placed to maximize capacitance contribution, while the outer first and third dielectric layers are configured to provide voltage stabilization and extend the operational voltage range.
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 enhances capacitance characteristics and reduces leakage current, enabling efficient operation of semiconductor devices with improved electrical characteristics.
Implementation Method 1
each of the first dielectric layer, the second dielectric layer, and the third dielectric layer includes a first crystal phase and a second crystal phase
Implementation Method 2
each of the first dielectric layer, the second dielectric layer, and the third dielectric layer includes an anti-ferroelectric region and a ferroelectric region
Implementation Method 3
The capacitance of the capacitor varies proportionally to the surface area of an electrode and the dielectric constant of a dielectric layer, and varies inversely with the equivalent oxide thickness of the dielectric layer
Data Source
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Figure 5
AI summary
A semiconductor device includes a capacitor structure including a bottom electrode, a first dielectric layer on the bottom electrode, a second dielectric layer on the first dielectric layer, a third dielectric layer on the second dielectric layer, and a top electrode on the third dielectric layer, where each of the first dielectric layer and the third dielectric layer includes zirconium oxide, the second dielectric layer includes hafnium-zirconium oxide, and each of the first dielectric layer, the second dielectric layer, and the third dielectric layer includes a first crystal phase and a second crystal phase.