Ferroelectric Memory Device Using Doped Aluminum Oxide
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Solution Overview
Problem
Current memory devices using ferroelectric materials face challenges in maintaining multiple polarization states due to low coercive electric fields, which limits their ability to achieve multi-leveling and increases the difficulty in scaling down memory cells.
Innovation Solution
The use of κ-aluminum oxide with specific dopants such as magnesium (Mg), silicon (Si), hafnium (Hf), tungsten (W), and ruthenium (Ru) in the ferroelectric layer, which enhances the coercive electric field and thermal stability, allowing for the realization of multi-leveling and high reliability in memory cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional ferroelectric materials are used in memory devices, then the device structure is simple, but the coercive electric field is low which limits multi-leveling capability
Solution Approach 1:
The patent changes the chemical composition parameters of the ferroelectric material by doping aluminum oxide with specific elements (Mg, Si, Hf, W, Ru) at controlled concentrations. This parameter modification increases the coercive electric field from conventional low values to sufficiently high levels that enable stable multi-leveling while preserving the basic memory cell structure
Solution Approach 2:
The patent creates composite ferroelectric materials by combining aluminum oxide with dopant elements (Mg, Si, Hf, W, Ru). These composite materials exhibit enhanced coercive electric field properties compared to pure aluminum oxide, enabling multi-leveling capability while maintaining structural simplicity
2Area of moving object
If the memory cell size is reduced for scaling, then the integration density increases, but the difficulty of maintaining stable polarization states increases
Solution Approach 1:
By modifying the chemical composition parameters of the ferroelectric layer through doping, the patent increases the coercive electric field strength. This allows smaller memory cell areas to maintain stable polarization states that would otherwise be unstable at reduced dimensions
3Reliability
If the coercive electric field is increased to enable multi-leveling, then the multi-leveling capability is improved, but the dielectric breakdown risk increases
Solution Approach 1:
The patent optimizes the dopant concentration parameters to achieve a balanced state where the coercive electric field is sufficiently high for multi-leveling but the overall dielectric strength remains adequate to prevent breakdown. Specific doping levels are controlled to maximize coercive field while maintaining reliability
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 increased coercive electric field and dielectric breakdown voltage of the κ-aluminum oxide layer enable stable maintenance of multiple polarization states, facilitating multi-leveling and improving the reliability and capacity of memory devices.
Implementation Method 1
data is written to a memory cell using polarization inversion of the ferroelectric. The polarization inversion is generated by applying an electric field from the outside to the ferroelectric.
Implementation Method 2
The increased coercive electric field and dielectric breakdown voltage of the κ-aluminum oxide layer enable stable maintenance of multiple polarization states
Data Source
AI summary
A memory device according to an embodiment includes a first conductive layer, a second conductive layer, and a first layer provided between the first conductive layer and the second conductive layer and containing aluminum oxide that contains at least one first element selected from the group consisting of magnesium (Mg), silicon (Si), hafnium (Hf), tungsten (W), and ruthenium (Ru), and the aluminum oxide is a ferroelectric.