AP-Pinned SOT-MRAM Cell With Heusler Layers for Stable AI Readback
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Solution Overview
Problem
Existing Topological insulator-based magnetoresistive random access memory (SOT-MTJ MRAM) faces challenges with large demagnetization in the MTJ data storage layer leading to bit degradation over time, poor signal-to-noise ratio (SNR) during read-back operations, and low operating temperature due to the low melting point of Topological insulators material, limiting high-density array manufacturing.
Innovation Solution
Implementing an anti-parallel pinned (AP-pinned) storage layer in conjunction with Topological Half Heusler Alloy (THHA) materials and doping or cluster co-depositing with ceramic elements like nitride, carbide, and oxide, or inert gases like N2, CO2, and O2, along with laminated THHA multilayer structures to enhance reliability and SNR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Topological insulator-based SOT-MTJ MRAM is used, then magnetoresistive random access memory functionality is achieved, but large demagnetization in the MTJ data storage layer leads to bit degradation over time
Solution Approach 1:
The patent inverts the conventional pinned layer configuration by implementing an anti-parallel pinned (AP-pinned) storage layer instead of a conventional parallel pinned structure. This inversion fundamentally changes the magnetic domain configuration, reducing demagnetization effects and preventing bit degradation over time, thereby resolving the reliability-stability contradiction.
Solution Approach 2:
The patent employs composite material structures including Topological Half Heusler Alloy (THHA) materials combined with ceramic elements (nitride, carbide, oxide) or inert gases (N2, CO2, O2) through doping or cluster co-depositing. These composite materials provide enhanced thermal stability and magnetic properties, simultaneously improving long-term reliability and maintaining bit stability at high operating temperatures.
2Measurement precision
If Topological insulator-based SOT-MTJ MRAM is used, then magnetoresistive random access memory functionality is achieved, but poor signal-to-noise ratio (SNR) during read-back operations occurs
Solution Approach 1:
The anti-parallel pinned configuration inverts the magnetic moment orientation relative to conventional structures, which fundamentally alters the read-back signal characteristics. This inversion enhances the signal-to-noise ratio by creating a more distinct magnetic state differentiation during read operations, directly improving measurement precision while reducing noise.
3Temperature
If Topological insulator-based SOT-MTJ MRAM is used, then magnetoresistive random access memory functionality is achieved, but low operating temperature due to low melting point of Topological insulators material limits high-density array manufacturing
Solution Approach 1:
The patent combines Topological Half Heusler Alloy (THHA) materials with ceramic elements (nitride, carbide, oxide) or inert gases (N2, CO2, O2) through doping or cluster co-depositing. These composite materials significantly elevate the melting point and thermal stability, enabling high operating temperatures that are essential for high-density array manufacturing and commercial production.
Solution Approach 2:
The patent changes the material parameters by introducing doping elements and cluster co-deposited ceramic components into the Topological Half Heusler Alloy structure. This parameter modification fundamentally alters the thermal properties, increasing the melting point from the original low temperature to a range suitable for high-volume manufacturing processes.
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
Enhances long-term reliability, reduces demagnetization field effects, improves thermal stability, and maintains high read-back SNR at elevated temperatures, crucial for high-volume AI device production.
Implementation Method 1
Topological insulators (TI) have been proposed for magnetoresistive random access memory (SOT-MTJ MRAM) utilizing the tunneling magnetoresistance (TMR) effect for reading data and the spin orbit torque (SOT) effect for writing data
Implementation Method 2
Topological insulators (TI) have been proposed for magnetoresistive random access memory (SOT-MTJ MRAM) utilizing the tunneling magnetoresistance (TMR) effect for reading data
Data Source
AI summary
An apparatus and a fabricating method therefor of magnetic in-memory computing AI inference chips utilizing magnetic Topological SOT-TMJ array unit cells comprises a spin orbit torque (SOT) cell having laminated Topological half Heusler Alloy layer, a magnetic tunnel junction (MTJ) cell having AP-pinned data storage layer, and a fabricating method therefor comprising materials and manufacturable processes providing a Topological SOT-MTJ having adjustable MTJ junction process and junction shape, wherein the SOT Topological layer and MTJ data storage layer are configured to generate memory writing, the MTJ TMR data storage layer/MgO/pin layer is configured to provide memory reading, and together a non-volatile memory SOT-MTJ array is formed to store programmable weight matrices for efficient AI in-memory computation.