Antiferromagnet SOT Memory Device Low Energy Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional spin torque transfer magnetoresistive random access memory (STT-MRAM) devices face challenges with high voltage and current-density requirements during programming, leading to density limitations and inefficiencies due to large write switching currents and voltages, which hinder the development of advanced non-volatile memory arrays.
Innovation Solution
The use of an antiferromagnet-based spin orbit torque (SOT) memory device with a free magnetic layer comprising antiferromagnetic materials, such as Ir, Pt, Mn, or Pd, and a ferromagnetic fixed magnetic layer, along with a spin orbit coupling interconnect, enables fast switching, high thermal stability, and flexible geometry, reducing stray fields and improving switching speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional STT-MRAM devices are used, then non-volatile memory functionality is achieved, but high voltage and current-density requirements limit device density and increase energy consumption
Solution Approach 1:
The patent changes the magnetic layer configuration from conventional ferromagnetic layers to an antiferromagnetic order parameter system. This fundamental parameter change enables switching at lower voltage and current densities while maintaining non-volatile memory functionality, directly resolving the energy consumption contradiction.
Solution Approach 2:
The invention employs a composite structure comprising an antiferromagnetic layer coupled with a ferromagnetic layer, where the antiferromagnetic material (such as MnIr alloy) provides the order parameter switching. This composite material approach enables low-energy switching while preserving memory functionality, addressing the voltage and current-density limitations of conventional STT-MRAM.
2Quantity of substance
If conventional MTJ based devices are used, then memory storage is achieved, but large write switching current and voltage requirements increase device area and reduce density
Solution Approach 1:
The patent fundamentally changes the switching mechanism from current-through-MTJ to voltage-controlled antiferromagnetic order parameter switching. This parameter change reduces the write current requirement from >100 μA to significantly lower values, enabling higher device density while maintaining storage capacity.
Solution Approach 2:
The invention introduces an antiferromagnetic layer as an intermediary between the control electrode and the ferromagnetic storage layer. This intermediary enables indirect switching through order parameter manipulation, reducing the direct current burden and allowing smaller device footprints for the same storage capacity.
3Productivity
If fast switching speed is achieved in memory devices, then productivity is improved, but thermal stability may be compromised
Solution Approach 1:
The patent employs a composite structure where the antiferromagnetic layer (providing fast switching through order parameter transitions) is coupled with a ferromagnetic layer (providing thermal stability through high anisotropy). This composite approach enables both fast switching and thermal stability simultaneously, resolving the contradiction between productivity and composition stability.
Solution Approach 2:
The invention replaces traditional thermal or magnetic field-based switching mechanisms with voltage-controlled antiferromagnetic order parameter switching. This substitution enables faster switching speeds while the coupled ferromagnetic layer maintains thermal stability, achieving both improved productivity and preserved composition stability.
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
The antiferromagnet-based SOT memory device achieves fast switching, high thermal stability, flexible geometry, and minimal stray fields, making it suitable for high-density, energy-efficient non-volatile memory applications like e-MRAM or e-SRAM, while the TAMR effect facilitates effective read-out of canting magnetization states.
Implementation Method 1
an interconnect (302) comprising a spin orbit coupling (SOC) material. A free magnetic layer (304) is on the interconnect (302)... during a write operation, a charge current is passed through the interconnect (302) to induce spin currents that manipulate an antiferromagnetic state
Implementation Method 2
a barrier material (306) is over the free magnetic layer (304)... which may comprise a tunneling barrier material
Implementation Method 3
In one embodiment, during a read-out operation, a charge current is passed through a top of the tunneling AMR device stack to induce spin currents that manipulate an antiferromagnetic state... which is detectable by the TAMR effect
Data Source
AI summary
A memory device comprises an interconnect comprises a spin orbit coupling (SOC) material. A free magnetic layer is on the interconnect, a barrier material is over the free magnetic layer and a fixed magnetic layer is over the barrier material, wherein the free magnetic layer comprises an antiferromagnet. In another embodiment, memory device comprises a spin orbit coupling (SOC) interconnect and an antiferromagnet (AFM) free magnetic layer is on the interconnect. A ferromagnetic magnetic tunnel junction (MTJ) device is on the AFM free magnetic layer, wherein the ferromagnetic MTJ comprises a free magnet layer, a fixed magnet layer, and a barrier material between the free magnet layer and the fixed magnet layer.