Perpendicular MRAM with Non-Uniform Switching Layer

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Solution Overview

Problem

Conventional magnetic random access memory (MRAM) devices face challenges with high switching current and power consumption, leading to larger cell sizes and higher costs, as well as reliability issues due to dielectric breakdown of the tunneling barrier layer.

Innovation Solution

A non-uniform switching based non-volatile magnetic memory element is developed, featuring a fixed layer, a barrier layer, a first free layer, a non-uniform switching layer, and a second free layer, where switching current is applied perpendicular to these layers, reducing the switching current and enabling lower power consumption and smaller cell sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional field-switching MRAM structures are used, then magnetic memory functionality is achieved, but switching current and power consumption are high

Engineering Contradiction:

Improveswitching currentVSAvoiddielectric breakdown

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent transitions from in-plane magnetization switching to perpendicular magnetization switching, changing the dimension of magnetic moment orientation. This perpendicular switching mechanism enables lower switching currents by utilizing spin-transfer torque more efficiently, directly addressing the high power consumption issue while maintaining reliability

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent modifies key magnetic parameters including introducing a non-uniform switching layer with specific perpendicular magnetic anisotropy, adjusting layer thicknesses, and optimizing material compositions. These parameter changes enable reduced switching current thresholds while preventing dielectric breakdown through controlled magnetic field distribution

Inventive Principle:

Principle #35Parameter changes

2Area of stationary object

If conventional MRAM cell designs are used, then memory functionality is achieved, but cell size and manufacturing cost are large/high

Engineering Contradiction:

Improvecell sizeVSAvoidmanufacturing cost

Core Design Contradiction:

Area of stationary objectVSEase of manufacture

Solution Approach 1:

The patent segments the magnetic memory cell into distinct functional layers including pinned layer, barrier layer, free layer, and non-uniform switching layer. This segmentation allows each layer to be optimized independently for specific functions, reducing overall cell footprint while maintaining manufacturability through specialized processing for each layer

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements a nested multi-layer magnetic tunnel junction structure where layers are stacked vertically with the non-uniform switching layer positioned between free layers. This nesting approach achieves three-dimensional integration, reducing the planar cell area while maintaining manufacturing feasibility through sequential deposition processes

Inventive Principle:

Principle #7Nested doll (Nesting)

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 reduced switching current and power consumption, leading to smaller cell sizes and lower manufacturing costs, while enhancing the reliability of the memory device by minimizing dielectric breakdown.

Implementation Method 1

switching current is applied, in a direction that is substantially perpendicular to the fixed, barrier, first free, non-uniform and the second free layers causing switching between states of the first, second free and non-uniform layers

Methodology Applied

Scientific EffectSpin-transfer torque:

Data Source

PatentUS8477530B2Non-uniform switching based non-volatile magnetic based memory

Publication Date: 2013.07.02 AVALANCHE TECHNOLOGY INC

AI summary

A non-uniform switching based non-volatile magnetic memory element includes a fixed layer, a barrier layer formed on top of the fixed layer, a first free layer formed on top of the barrier layer, a non-uniform switching layer (NSL) formed on top of the first free layer, and a second free layer formed on top of the non-uniform switching layer. Switching current is applied, in a direction that is substantially perpendicular to the fixed layer, barrier layer, first free layer, non-uniform switching layer and the second free layer causing switching between states of the first free layer, second free layer and non-uniform switching layer with substantially reduced switching current.