SOT-MRAM Channel Structure With Dielectric Dusting for Lower Write Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In SOT-MRAM systems, the resistance of the SOT channel layer is often very small compared to other components, leading to elevated power consumption due to increased resistance values of the MRAM cell, which is undesirable.
Innovation Solution
A new structure for the SOT channel is introduced, featuring multiple heavy metal layers with discrete dielectric dusting layers between them, where the dielectric molecules are scattered and controlled to be thinner than their size, enhancing the conversion of in-plane current to spin torque with increased vertical spin current efficiency, thus reducing the required write current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the SOT channel layer resistance is increased to match other MRAM components, then power consumption is reduced, but the conversion efficiency from in-plane current to spin torque decreases
Solution Approach 1:
The SOT channel is constructed as a composite structure with alternating heavy metal layers and dielectric dusting layers. The heavy metal layers provide high spin-orbit coupling for efficient spin torque generation, while the dielectric dusting layers increase the overall resistance of the channel. This composite structure allows simultaneous optimization of both conversion efficiency and power consumption.
Solution Approach 2:
The dielectric dusting layers are positioned specifically at the interfaces between heavy metal layers, creating localized regions of high resistance. This local modification increases the overall channel resistance without significantly impacting the spin torque generation in the heavy metal regions, thus resolving the contradiction between resistance and conversion efficiency.
2Loss of energy
If multiple heavy metal layers with dielectric dusting layers are introduced to increase resistance, then power consumption is reduced, but the device structure becomes more complex
Solution Approach 1:
The SOT channel is segmented into multiple thin heavy metal layers separated by dielectric dusting layers. This segmentation increases resistance through the cumulative effect of multiple interfaces while maintaining relatively simple individual layer structures. The segmented design achieves the desired resistance increase without requiring a completely new device architecture.
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 structure improves the conversion efficiency from in-plane current to spin torque, allowing a lower write current to achieve the same spin current and torque, offsetting the negative effects of increased resistance and reducing power consumption.
Implementation Method 1
Spin torque is induced by the in-plane current injected through the heavy metal layer under the spin-orbit coupling effect
Implementation Method 2
which generally includes one or more of the Rashba effect or the spin Hall effect (SHE effect)
Implementation Method 3
which generally includes one or more of the Rashba effect or the spin Hall effect (SHE effect)
Implementation Method 4
Due to the tunnel magnetoresistance effect, the resistance value between the reference layer and the free layer changes with the magnetization polarity switch in the free layer
Data Source
AI summary
The disclosure is directed to spin-orbit torque (“SOT”) magnetoresistive random-access memory (“MRAM”) (“SOT-MRAM”) structures and methods. A SOT channel of the SOT-MRAM includes multiple heavy metal layers and one or more dielectric dusting layers each sandwiched between two adjacent heavy metal layers. The dielectric dusting layers each include discrete molecules or discrete molecule clusters of a dielectric material scattered in or adjacent to an interface between two adjacent heavy metal layers.