Segmented MRAM Free Layer for Lower Write Current Scaling

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Solution Overview

Problem

As MRAM devices scale down, the ability to supply write current and voltage decreases, leading to increased power consumption and exacerbated tailing bits due to multiple domains in the free magnetic layer, which hinders critical dimension scaling and storage capacity.

Innovation Solution

A segregated structure for the free magnetic layer with multiple magnetic material pieces separated by a non-magnetic segregation layer replaces the continuous single layer, reducing write current, voltage, and power requirements while maintaining or improving storage capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a continuous single layer free magnetic layer is used, then storage capacity is maintained, but write current and power consumption increase as devices scale down

Engineering Contradiction:

Improvewrite currentVSAvoidstorage capacity

Core Design Contradiction:

Use of energy by moving objectVSQuantity of substance

Solution Approach 1:

The free magnetic layer is divided into multiple magnetic material pieces separated by non-magnetic material layers, creating a segregated structure that reduces write current requirements while maintaining storage capacity through distributed magnetic domains

Inventive Principle:

Principle #1Segmentation

2Use of energy by moving object

If a continuous single layer free magnetic layer is used, then storage capacity is maintained, but power consumption increases as devices scale down

Engineering Contradiction:

Improvepower consumptionVSAvoidstorage capacity

Core Design Contradiction:

Use of energy by moving objectVSQuantity of substance

Solution Approach 1:

The free magnetic layer is divided into multiple magnetic material pieces separated by non-magnetic material layers, creating a segregated structure that reduces power consumption while maintaining storage capacity through distributed magnetic domains

Inventive Principle:

Principle #1Segmentation

3Productivity

If critical dimension scaling is pursued, then device density increases, but tailing bits increase due to multiple domains in continuous free magnetic layer

Engineering Contradiction:

Improvedevice densityVSAvoidtailing bits

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The free magnetic layer is segmented into discrete magnetic material pieces separated by non-magnetic layers, which eliminates unwanted multiple domains and reduces tailing bits while enabling continued critical dimension scaling for higher device density

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the free magnetic layer have distinct magnetic properties through the segregated structure, with each magnetic material piece having controlled magnetization characteristics that improve data reliability and reduce tailing bits

Inventive Principle:

Principle #3Local quality

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 segregated free magnetic layer structure decreases write current, voltage, and power consumption while minimizing the impact of domain scaling on MRAM cell properties, enhancing storage capacity and system flexibility.

Implementation Method 1

an MRAM cell is formed by a magnetic tunneling junction (MTJ) comprising two ferromagnetic layers which are separated by a thin insulating barrier, and operates by tunneling of electrons between the two ferromagnetic layers through the insulating barrier

Methodology Applied

Scientific EffectElectron tunneling:

Data Source

PatentUS20240373649A1Magnetic random access memory and manufacturing method thereof

Publication Date: 2024.11.07 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A semiconductor device includes a magnetic random access memory (MRAM) cell. The MRAM cell includes a first magnetic layer disposed over a substrate, a first non-magnetic material layer made of a non-magnetic material and disposed over the first magnetic layer, a second magnetic layer disposed over the first non-magnetic material layer, and a second non-magnetic material layer disposed over the second magnetic layer. The second magnetic layer includes a plurality of magnetic material pieces separated from each other.