Magnetic Memory Read Disturb Control via Voltage Bias
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetoresistive random access memories (MRAMs) face challenges in avoiding read disturb due to the high probability of data-rewriting during read operations, which is exacerbated by the difficulty in reducing the pulse width of the read current without compromising read sensitivity and incurring delays from wiring issues.
Innovation Solution
A magnetic memory design that includes a magnetic multilayer structure with a control electrode on the side surface, applying a voltage to control the energy barrier for magnetization switching, thereby increasing the stability of the magnetization direction and reducing the risk of read disturb by adjusting the magnetic anisotropy energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pulse width of read current is reduced to avoid read disturb, then the probability of data-rewriting is reduced, but the read sensitivity decreases and delay in current pulse increases
Solution Approach 1:
The patent changes the magnetic anisotropy energy parameter by applying a voltage to the control electrode, which modifies the energy barrier for magnetization switching. This allows the system to operate with shorter current pulses while maintaining sufficient switching reliability, thereby reducing read disturb without sacrificing read sensitivity.
Solution Approach 2:
The patent applies a voltage to the control electrode before the read current flows, which preliminarily adjusts the magnetic anisotropy energy and prepares the storage layer for stable magnetization switching. This preliminary action ensures that even with reduced pulse width, the magnetization switching occurs reliably without causing read disturb.
2Reliability
If the pulse width of read current is reduced to avoid read disturb, then the probability of data-rewriting is reduced, but the delay in current pulse caused by wiring increases
Solution Approach 1:
By changing the magnetic anisotropy energy through voltage application to the control electrode, the patent enables faster magnetization switching dynamics. This allows the use of narrower current pulses that can be applied more quickly, reducing the timing delay caused by wiring while still preventing read disturb.
3Measurement precision
If the read current is increased to improve read sensitivity, then the read sensitivity improves, but the probability of read disturb increases
Solution Approach 1:
The patent applies a voltage locally to the control electrode positioned adjacent to the storage layer, which creates a localized change in magnetic anisotropy energy. This local modification allows the read current to be increased for better sensitivity without proportionally increasing the risk of read disturb, as the energy barrier is enhanced only where needed.
Solution Approach 2:
The patent dynamically changes the magnetic anisotropy energy parameter by applying voltage to the control electrode during read operations. This allows the system to tolerate higher read currents for improved sensitivity while the adjusted energy barrier prevents unwanted magnetization switching and read disturb.
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 approach effectively reduces the probability of read disturb and allows for efficient magnetization switching, providing a margin for variations and fluctuations in pulse widths, thus enhancing the reliability of MRAM operations.
Implementation Method 1
A magnetic memory design that includes a magnetic multilayer structure with a control electrode on the side surface, applying a voltage to control the energy barrier for magnetization switching, thereby increasing the stability of the magnetization direction and reducing the risk of read disturb by adjusting the magnetic anisotropy energy.
Implementation Method 2
The electric resistance of the MTJ element switches between a low-resistance state and a high-resistance state when a current flows in a direction perpendicular to the film plane of the MTJ element depending on whether the magnetizations of the storage layer and of the reference layer are parallel or antiparallel to each other.
Implementation Method 3
If the current has an intensity of a predetermined threshold value, the direction of magnetization of the storage layer can be switched. As a result, the spin transfer torque acts on the magnetization of the storage layer to turn to the direction parallel to the direction of magnetization of the reference layer.
Data Source
AI summary
A magnetic memory according to an embodiment includes at least one MTJ element, the MTJ element including: a magnetic multilayer structure including a first magnetic layer in which a direction of magnetization is fixed, a second magnetic layer in which a direction of magnetization is changeable, and a tunnel barrier layer located between the first and second magnetic layers; a first electrode provided on a first surface of the magnetic multilayer structure; a second electrode provided on a second surface of the magnetic multilayer structure; an insulating film provided on a side surface of the magnetic multilayer structure; and a control electrode provided on the side surface of the magnetic multilayer structure with the insulating film located therebetween, a voltage being applied to the control electrode in a read operation, which increases an energy barrier for changing the magnetization of the second magnetic layer.