Nano-Current-Channel MRAM Free Layer for Density Stability
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Solution Overview
Problem
Current magnetic random access memory (MRAM) technologies face challenges with high switching current density and thermal instability due to the limitations of scaling down memory cell size, leading to issues with power consumption, compatibility, and reliability.
Innovation Solution
A magnetic storage memory device with a composite free layer structure, including a nano-current-channel layer sandwiched between two free sub-layers, which reduces switching current density and maintains thermal stability by confining current perpendicular to the layers, allowing for efficient magnetization switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If memory cell size is scaled down to increase recording density, then storage capacity is improved, but thermal stability deteriorates
Solution Approach 1:
The patent applies local quality by creating a nano-current-channel layer with specific magnetic properties (high magnetocrystalline anisotropy) localized within the free layer structure. This localized region provides enhanced thermal stability without requiring the entire memory cell to be larger, thus resolving the contradiction between high recording density and thermal stability.
Solution Approach 2:
The patent employs composite materials by integrating a nano-current-channel layer composed of magnetic nanoparticles embedded in a matrix material within the free layer. This composite structure combines the high anisotropy of magnetic particles with the structural integrity of the matrix, achieving both high recording density and thermal stability simultaneously.
2Use of energy by moving object
If switching current density is reduced to lower power consumption, then energy efficiency is improved, but magnetization switching reliability deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the magnetic anisotropy energy barrier through the introduction of the nano-current-channel layer with high magnetocrystalline anisotropy. This changes the switching characteristics, allowing for reduced switching current density while maintaining reliable magnetization switching through the engineered energy landscape.
3Stability of the object's composition
If aspect ratio of memory element is increased to improve thermal stability, then thermal stability is improved, but device scalability deteriorates
Solution Approach 1:
The patent applies local quality by concentrating the thermal stability enhancement function in the nano-current-channel layer with high magnetocrystalline anisotropy, rather than requiring the entire memory element to have high aspect ratio. This localized approach maintains thermal stability while preserving device scalability and simple geometry.
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 solution achieves a significant reduction in switching current density while maintaining high thermal stability, addressing the dilemma of high recording density and thermal instability, and enabling scalable and reliable memory solutions.
Implementation Method 1
MRAMs may be driven by magnetic field or by spin current. The latter has been known to attract a lot of attention due to its simplified design, reliability, and less cross talk.
Implementation Method 2
when switching current is applied to the memory element, in a direction that is substantially perpendicular to the layers of the memory element, local magnetic moments of the NCC layer switch the state of the memory element
Implementation Method 3
a high shape anisotropy or high magnetocrystalline anisotropy (Ku) material need be used in order to keep a relatively high Ku*V (or KuV) to resist thermal fluctuation, which acts to destroy the stored data
Implementation Method 4
a high shape anisotropy or high magnetocrystalline anisotropy (Ku) material need be used in order to keep a relatively high Ku*V (or KuV) to resist thermal fluctuation
Data Source
AI summary
One embodiment of the present invention includes a memory element having a composite free layer including a first free sub-layer formed on top of the bottom electrode, a nano-current-channel (NCC) layer formed on top of the first free sub-layer, and a second free sub-layer formed on top of the NCC layer, wherein when switching current is applied to the memory element, in a direction that is substantially perpendicular to the layers of the memory element, local magnetic moments of the NCC layer switch the state of the memory element.