Magnetic Memory with Integrated MTJ and OTP Cells for Data Reliability
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Solution Overview
Problem
Existing magnetic memory devices face challenges in achieving high product reliability, specifically in, and are, are, not limited to those mentioned above and additional challenges in improving product reliability, which are not effectively addressed in the field of applications where stability and security of data are important, and needs the present disclosure aims to provide a magnetic memory device in which product reliability is improved. The objects of the present disclosure are not limited to those mentioned above and additional objects of the present disclosure, which are not mentioned herein, will be clearly understood by those skilled in the art from the following description of the present disclosure.
Innovation Solution
A magnetic memory device is provided with a substrate and a memory cell array, including memory unit cells and one-time-programmable (OTP) unit cells. The memory unit cells include a first magnetic tunnel junction element and a wiring structure, while the OTP unit cells include spaced apart second and third magnetic tunnel junction elements, along with specific wiring structures to enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If STT-MRAM is highly integrated to achieve high-speed operation and low current consumption, then productivity and energy efficiency are improved, but product reliability deteriorates due to increased complexity and potential for data corruption
Solution Approach 1:
The memory device is segmented into distinct functional regions: a first memory region containing multiple memory unit cells for high-speed reversible storage, and a second memory region containing multiple one-time-programmable unit cells for permanent data storage. This segmentation allows each region to be optimized for its specific function, with the OTP region providing reliability through irreversible storage and the MRAM region providing speed through reversible storage.
Solution Approach 2:
Different regions of the memory device are assigned different storage characteristics. The first memory region uses standard MRAM cells with reversible magnetization states for fast access, while the second memory region uses OTP cells with irreversible magnetization reversal for permanent storage. This local differentiation of storage quality allows the system to achieve both high speed and high reliability simultaneously.
2Reliability
If OTP memory is used to ensure data stability and security, then reliability is improved, but adaptability deteriorates because data cannot be changed after programming
Solution Approach 1:
The memory device is divided into two functional regions: the first memory region for reversible, reprogrammable storage and the second memory region for permanent, non-reprogrammable storage. This segmentation allows the system to maintain adaptability where needed while ensuring reliability where required.
Solution Approach 2:
The memory device provides multiple storage functions within a single integrated structure. It can perform both reversible MRAM operations for flexible data storage and irreversible OTP operations for permanent data retention, making the device universally applicable to various storage requirements including both adaptable and stable data scenarios.
3Reliability
If multiple magnetic tunnel junction elements are integrated in OTP unit cells, then reliability is improved through redundancy, but device complexity increases
Solution Approach 1:
The OTP unit cell is segmented into multiple magnetic tunnel junction elements (second MTJ, third MTJ, fourth MTJ) with distinct wiring connections. The second MTJ is connected to cell transistors for programming control, while the third and fourth MTJs are spaced apart and connected through separate wiring structures, creating redundancy that improves reliability without excessive complexity.
Solution Approach 2:
Different wiring structures are provided for different MTJ elements based on their specific functions. The second MTJ has direct transistor connections for active programming control, while the third and fourth MTJs have spaced-apart connections optimized for their specific roles in the redundancy structure, allowing each component to be optimized locally for its function.
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 magnetic memory device achieves improved product reliability by integrating memory unit cells and OTP unit cells, ensuring high-speed operation and low current consumption, while maintaining data integrity and security.
Implementation Method 1
STT-MRAM for storing information using a spin transfer torque (STT) phenomenon is being studied. The STT-MRAM may induce a magnetization reversal by applying a direct current to a magnetic tunnel junction element to store information.
Data Source
AI summary
A magnetic memory device includes a substrate; and a memory unit cell array, which includes a memory unit cell and a one-time-programmable (OTP) unit cell, on the substrate. The memory unit cell includes a first magnetic tunnel junction element on the substrate, and a wiring structure connecting the substrate with the first magnetic tunnel junction element. The OTP unit cell includes a connection wiring on the substrate, a second magnetic tunnel junction element and a third magnetic tunnel junction element, which are spaced apart from each other on the connection wiring, a first lower wiring structure and a second lower wiring structure, which connects the substrate with the connection wiring, spaced apart from each other, and a first upper wiring structure connecting the connection wiring with the second magnetic tunnel junction element.