Mixed Ferroelectric Dielectric Capacitor for Low-Leakage DRAM
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Solution Overview
Problem
Capacitor devices in DRAM cells face challenges with high dielectric constants leading to decreased band gaps and increased leakage currents, which deteriorate their operating characteristics.
Innovation Solution
A capacitor device with a dielectric layer composed of mixed ferroelectrics and antiferroelectrics, including fluorite-based oxides like hafnium oxide and zirconium oxide, dispersed with dopants, enhances the dielectric layer's properties, resulting in a nonlinear charge-voltage curve and improved charge storage capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a dielectric material with high dielectric constant is used to secure capacitance, then capacitance is improved, but leakage current increases and band gap decreases
Solution Approach 1:
The patent employs a composite dielectric material comprising both ferroelectric and antiferroelectric phases within a fluorite-based oxide structure. This composite approach allows the material to exhibit high dielectric constant for improved capacitance while the antiferroelectric phase suppresses leakage current by providing a higher energy barrier for charge carriers, thus resolving the contradiction between capacitance and leakage current
Solution Approach 2:
The patent utilizes dopant materials to modify the physical and chemical parameters of the fluorite-based oxide. By controlling doping concentration and composition, the dielectric constant is enhanced for higher capacitance while simultaneously adjusting the band gap and leakage characteristics, thereby resolving the trade-off between capacitance and leakage current through parameter optimization
2Quantity of substance
If ferroelectrics and antiferroelectrics are mixed in the dielectric layer, then charge storage capability is improved with nonlinear charge-voltage curve, but device complexity increases
Solution Approach 1:
The patent creates a composite dielectric layer where ferroelectric and antiferroelectric phases are integrated at the material level within a single fluorite-based oxide structure. This approach achieves enhanced charge storage capability through the nonlinear charge-voltage characteristic while avoiding structural complexity by maintaining a unified material system rather than separate layers
Solution Approach 2:
The patent implements local quality differentiation by dispersing ferroelectric and antiferroelectric phases throughout the dielectric layer with controlled spatial distribution. The ferroelectric phase (0-40 volume percent) provides polarization for charge storage while the antiferroelectric phase provides stability and leakage control, achieving functional differentiation without increasing overall device structural complexity
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 mixed dielectric layer provides increased capacitance and reduced leakage current, enabling more efficient charge storage and discharge with a non-linear profile, suitable for dynamic random access memory applications.
Implementation Method 1
a dielectric layer between the first electrode and the second electrode and including a dielectric material in which ferroelectrics and antiferroelectrics are mixed with each other
Implementation Method 2
A transition voltage at a point where a linear slope increases as a voltage increases in a charge (Q)-voltage (V) curve for the dielectric layer may be less than a transition voltage at a point where a linear slope increases as a voltage increases in a charge (Q)-voltage (V) curve for the antiferroelectrics
Data Source
AI summary
A capacitor device and a semiconductor device including the capacitor device are provided. The capacitor device includes first and second electrodes spaced apart from each other, and a dielectric layer provided between the first electrode and the second electrode. The dielectric layer includes a dielectric material in which ferroelectrics and antiferroelectrics are mixed with each other.