Magnetic Memory Structure Reducing External Terminals
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Solution Overview
Problem
Current magnetic memories, such as MRAM, face challenges in achieving high integration and efficient data storage due to limitations in the number of external terminals and resistance value differences required for read and write operations, which affect the degree of integration and manufacturing margins.
Innovation Solution
A magnetic memory structure comprising a first magnetic layer, a conductive layer, an intermediate layer, and additional magnetic layers, with a specific electrode configuration that allows for spin injection and exchange bias to control magnetization, enabling reduced external terminals and increased integration by using a single set of terminals for both read and write operations, and maintaining high TMR ratios without degrading write characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional magnetic memory structure is used, then the device is simpler to manufacture, but the degree of integration is limited and the number of external terminals increases
Solution Approach 1:
The patent merges the read and write operation terminals into a single set of external terminals. The magnetic memory cell uses the same terminal structure for both read and write operations, eliminating the need for separate terminal sets and thereby increasing the degree of integration without significantly complicating the manufacturing process.
Solution Approach 2:
The patent implements multi-functionality by designing the magnetic memory cell to perform both read and write operations through a unified terminal structure. The first and second magnetic layers, along with the intermediate layer, are configured to enable both operations using the same external terminals, making the device more integrated and efficient.
2Measurement precision
If the resistance value difference between high and low resistance states is increased, then the read operation becomes more reliable, but the write characteristics are degraded
Solution Approach 1:
The patent applies local quality by introducing an intermediate layer with specific magnetic properties between the first and second magnetic layers. This intermediate layer has a magnetization direction that is oblique to the magnetization directions of the adjacent magnetic layers, creating localized magnetic field effects that enable precise control of the resistance state transition while maintaining good write characteristics.
Solution Approach 2:
The patent changes the magnetic parameter configuration by setting the magnetization direction of the intermediate layer at a specific angle (oblique direction) relative to the magnetization directions of the first and second magnetic layers. This parameter change allows the system to achieve a larger resistance value difference for reliable read operations while maintaining the ability to perform write operations effectively through spin transfer torque.
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 configuration enhances the degree of integration, reduces the number of external terminals, and increases the manufacturing margin by allowing higher resistance values in the high resistance state without degrading write characteristics, thus improving the overall performance and efficiency of magnetic memory cells.
Implementation Method 1
a three terminal magnetic random access memory (MRAM; Magnetic Random Access Memory) using torque which is originally caused by spin-orbit interaction has been proposed
Implementation Method 2
The intermediate layer is provided between the second magnetic layer and the first magnetic layer
Data Source
AI summary
According to one embodiment, the magnetic memory includes a structure including a first magnetic layer and a conductive layer, a second magnetic layer, an intermediate layer, a third magnetic layer, and a fourth magnetic layer. The first magnetic layer is provided between the second magnetic layer and the conductive layer. The intermediate layer is provided between the second magnetic layer and the first magnetic layer. The third magnetic layer is provided between a second electrode and the intermediate layer. The fourth magnetic layer is provided between a first electrode and the intermediate layer. Further, the magnetic memory includes a first conductive-type first semiconductor layer electrically connected with the first electrode, a first conductive-type second semiconductor layer electrically connected with the second magnetic layer, and a second conductive-type third semiconductor layer electrically connected with the first semiconductor layer and the second semiconductor layer.