Self-Referenced MRAM Element Parallel Field Line Branches

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Solution Overview

Problem

Conventional self-referenced MRAM devices require high field currents to generate sufficient magnetic fields for writing and reading, which is detrimental in low power applications and those with high surface density of MRAM elements, as they consume more power and are inefficient in generating magnetic fields with small field lines.

Innovation Solution

The MRAM element employs a field line with parallel branches and cladding to focus the magnetic field, allowing reduced field currents while maintaining or enhancing the magnetic field strength, thereby improving selectivity and efficiency in varying magnetoresistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high field currents are used to generate sufficient magnetic fields for writing and reading MRAM cells, then the magnetic field strength is improved, but the power consumption increases and becomes detrimental in low power applications

Engineering Contradiction:
Improvemagnetic field strengthVSAvoidpower consumption
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The field line is divided into two parallel branches that are electrically connected in parallel. Each branch is arranged to pass a portion of the field current and generate a magnetic field component. The combined effect of both branches produces a stronger magnetic field than a single branch would generate with the same total current, thereby reducing the required field current and power consumption while maintaining sufficient magnetic field strength for MRAM cell writing and reading.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines the magnetic field generation from two parallel field line branches to achieve a stronger overall magnetic field. By merging the contributions from both branches, the system generates the required magnetic field strength with reduced current compared to a conventional single-branch field line, thus lowering power consumption in MRAM devices.

Inventive Principle:
Principle #5Merging (Combining)

2Strength

If high field currents are used to generate sufficient magnetic fields, then the magnetic field strength is improved, but the efficiency of generating magnetic fields with small field lines deteriorates

Engineering Contradiction:
Improvemagnetic field strengthVSAvoidefficiency of magnetic field generation
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The field line is segmented into two parallel branches, allowing each branch to be optimized for compact dimensions. The parallel configuration enables the magnetic fields from both branches to add constructively, achieving high magnetic field strength from small-sized field lines with improved efficiency, suitable for high surface density MRAM devices.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By merging the magnetic field contributions from two parallel branches in a compact configuration, the patent achieves efficient magnetic field generation in small field lines. This combined approach maximizes the magnetic field output relative to the physical size of the field line structure.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If conventional field line configurations are used, then the device structure is simple, but the selectivity in varying magnetoresistance of specific MRAM cells deteriorates

Engineering Contradiction:
Improvefield line structure complexityVSAvoidselectivity in magnetoresistance variation
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The field line is segmented into two parallel branches with specific geometric arrangements relative to the MRAM cells. This segmentation enables selective addressing of MRAM cells by controlling which branch receives the field current, thereby improving selectivity in varying magnetoresistance of specific cells while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The parallel branch configuration allows different regions of the field line structure to have different functions. Each branch can be positioned and dimensioned to optimally affect specific MRAM cells, providing local optimization of magnetic field distribution and improving selectivity without requiring complex control circuitry.

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

This configuration enables the use of reduced field currents to generate stronger magnetic fields, enhancing the selectivity and efficiency of magnetoresistance variation in MRAM elements, particularly beneficial for low power applications and high-density MRAM devices.

Implementation Method 1

a field line (5) for passing a field current (51) and generating a magnetic field (52)

Methodology Applied
Scientific EffectMagnetic field generation: Electromagnetic Induction

Implementation Method 2

a magnetic field (52) generated by a field current (51) passing in the field line (5) varies a magnetoresistance of the magnetic tunnel junction (2)

Methodology Applied
Scientific EffectMagnetoresistance variation: Magnetoresistance

Data Source

PatentEP2722902B1Self-referenced MRAM element and device having improved magnetic field
Publication Date: 2016.11.30 CROCUS TECHNOLOGY
  • EP2722902B1 patent drawingFigure 1~2
  • EP2722902B1 patent drawingFigure 3~4
  • EP2722902B1 patent drawingFigure 5~6

AI summary

Self-reference-based MRAM element (1) comprising: a first magnetic tunnel junctions (2) and a second magnetic tunnel junctions (2'), each having a magnetoresistance that can be varied; and a field line (5) for passing a field current (51) destined to vary the magnetoresistance of the first and second magnetic tunnel junctions (2); the field line (5) comprising a first branch (5') and a second branch (5") both branch (5', 5") comprises a cladding (6); the first branch (5') being arranged for passing a first portion (51') of the field current to selectively vary the magnetoresistance of the first magnetic tunnel junction (2), and the second branch (5") being electrically connected in parallel with the first branch (5') and arranged for passing a second portion (51") of the field current to selectively vary the magnetoresistance of the second magnetic tunnel junction (2'). The present disclosure also concerns a MRAM device comprising a plurality of the MRAM elements. The self-referenced MRAM element and MRAM device can use a reduced field current.