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 each part connected to the spin-orbit torque layer, and a blocking layer is formed to ensure that the current flows directly through the spin-orbit torque layer, reducing bypassing and enhancing current efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the injection layer is designed as a continuous layer in conventional bottom-pinned SOT-MRAM, then the structure is simple and easy to manufacture, but the current bypasses through the injection layer causing inefficient current usage
Solution Approach 1:
The injection layer is divided into two separate parts: a first injection layer part and a second injection layer part. The first part is positioned over and electrically connected to the capping layer at a first end, while the second part is positioned over and electrically connected to the capping layer at a second end. This segmentation prevents current from bypassing through the injection layer and forces it to flow through the spin-orbit torque layer, significantly improving current efficiency.
2Power
If the transistor channel width is increased to compensate for inefficient current usage, then sufficient current can be supplied to achieve memory operation, but the memory scaling is hindered
Solution Approach 1:
By segmenting the injection layer into two separate parts that connect to opposite ends of the capping layer, the patent ensures that current flows through the spin-orbit torque layer rather than bypassing through the injection layer. This improves current efficiency, allowing smaller transistor channel widths to be used while still achieving the required current supply capability, thus enabling continued memory scaling.
3Reliability
If more current is applied to overcome the bypassing effect, then the memory operation can be achieved, but the energy consumption increases
Solution Approach 1:
The segmented injection layer structure forces current to flow through the spin-orbit torque layer, maximizing the utilization of applied current for the intended memory operation. This eliminates the waste of current that occurs when it bypasses through the injection layer, thereby achieving reliable memory operation with lower energy consumption.
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 achieves efficient current usage, reducing the required current and transistor width, thereby improving the scaling of 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
performing a photolithography process to pattern the bottom electrode layer, the pinned layer, the reference layer, the free layer, the spin-orbit torque layer and the capping layer into a memory unit
Implementation Method 3
performing an annealing process to make oxygen atoms in the metal oxide layer into the injection layer, thereby oxidizing the part of injection layer directly connected with the metal oxide layer into a blocking layer
Implementation Method 4
oxidizing the part of injection layer directly connected with the metal oxide layer into a blocking layer
Data Source
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.