Bottom-Pinned SOT-MRAM Injection Layout to Prevent Current Bypass
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Solution Overview
Problem
Current bottom-pinned spin-orbit torque magnetic random access memory (SOT-MRAM) designs suffer from inefficient current usage due to current bypassing through the injection layer, requiring increased current and transistor channel width, which hinders memory scaling.
Innovation Solution
The injection layer is divided into two parts, with a blocking layer formed at the middle section to connect each part to the spin-orbit torque layer, ensuring that the applied current flows directly through the spin-orbit torque layer, thereby preventing bypassing and improving current efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the injection layer is designed as a continuous layer in bottom-pinned SOT-MRAM, then the structure is simple and easy to manufacture, but the current bypasses through the injection layer instead of flowing through the spin-orbit torque layer, reducing current efficiency
Solution Approach 1:
The injection layer is divided into two separate parts: a first injection layer connected to the anode and a second injection layer connected to the cathode. The spin-orbit torque layer is positioned between these two injection layer parts, forming a sandwich structure. This segmentation prevents current from bypassing through a continuous injection layer and forces it to flow through the spin-orbit torque layer, thereby improving current efficiency while maintaining manufacturing simplicity.
2Reliability
If more current is applied to compensate for bypassing losses, then the spin-orbit torque effect can be achieved, but the transistor channel width must be increased, which hinders memory scaling
Solution Approach 1:
By segmenting the injection layer into two parts with the spin-orbit torque layer in between, the patent ensures that current flows through the spin-orbit torque layer rather than bypassing it. This reduces the total current required for operation, allowing transistors to maintain smaller channel widths and enabling continued memory scaling without compromising operational reliability.
Solution Approach 2:
The spin-orbit torque layer acts as an intermediary between the first and second injection layer parts. It receives spin-polarized current from the first injection layer and transfers it to the second injection layer, ensuring efficient current utilization for generating the spin-orbit torque effect needed for reliable memory operation.
3Device complexity
If the current flows partially through the spin-orbit torque layer, then the injection layer structure is simpler, but higher current is required which increases power consumption
Solution Approach 1:
The injection layer is segmented into two distinct parts with the spin-orbit torque layer positioned between them. This structural segmentation creates a current path that must flow through the spin-orbit torque layer, maximizing current efficiency and minimizing power consumption while keeping the overall structure relatively simple and manufacturable.
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 design reduces the current required for operation, minimizes transistor width, and enhances memory scaling by ensuring efficient current usage, allowing for more compact and efficient SOT-MRAM devices.
Implementation Method 1
the spin-orbit torque layer is over the magnetic unit and is applied with current through an injection layer to generate spin moment and achieve the effect of flipping the magnetic moment of magnetic films
Implementation Method 2
a blocking layer formed at the middle section to connect each part to the spin-orbit torque layer, ensuring that the applied current flows directly through the spin-orbit torque layer, thereby preventing bypassing
Data Source
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AI summary
A bottom-pinned spin-orbit torque magnetic random access memory (SOT-MRAM) is provided in the present invention, including a substrate, a bottom electrode layer on the substrate, a magnetic tunnel junction (MTJ) on the bottom electrode layer, a spin-orbit torque (SOT) layer on the MTJ, a capping layer on the SOT layer, and an injection layer on the capping layer, wherein the injection layer is divided into individual first part and second part, and the first part and the second part are connected respectively with two ends of the capping layer.