Dual-Free-Layer MRAM Writing Without Precise Pulse Width Control

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Solution Overview

Problem

The existing voltage-controlled MRAM technology requires precise management of pulse width for effective writing, making the writing process more difficult and complex.

Innovation Solution

The proposed magnetoresistive effect memory system includes a magnetoresistive effect element with a voltage-controlled magnetic anisotropy effect layer and a non-voltage-controlled magnetic anisotropy effect layer, along with a magnetization fixed layer, which simplifies the writing process by allowing the magnetization vector of the free layers to be inverted without precise pulse width management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If voltage-controlled MRAM uses precession of magnetization vector for writing, then data can be written by inverting magnetization direction, but precise management of pulse width is required which increases writing difficulty

Engineering Contradiction:

Improvewriting success rateVSAvoidwriting process complexity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The magnetization free layer is divided into two separate layers: a voltage-controlled magnetic anisotropy effect layer and a non-voltage-controlled magnetic anisotropy effect layer. Each layer has distinct characteristics and functions, allowing independent optimization of their properties to achieve reliable writing without precise pulse width control.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the magnetic anisotropy parameter of the voltage-controlled layer by applying voltage, which modifies the energy landscape and allows the magnetization vector to be inverted without requiring precise timing control of the voltage pulse width.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If precise pulse width management is implemented, then writing success rate improves, but device complexity increases

Engineering Contradiction:

Improvewriting success rateVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The dual-layer structure enables self-service writing where the voltage application to the VCMA layer automatically triggers the magnetization inversion in the NVCMA layer through exchange coupling, eliminating the need for complex external timing control mechanisms.

Inventive Principle:

Principle #25Self-service

3Stability of the object's composition

If voltage is applied to control magnetization inversion, then nonvolatile storage is achieved, but precise timing control is required which reduces productivity

Engineering Contradiction:

Improvedata retentionVSAvoidwriting speed

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The VCMA layer is prepared in advance with voltage-controlled magnetic anisotropy properties, so that when voltage is applied, the magnetization inversion occurs rapidly and reliably without requiring precise timing, thereby improving writing speed while maintaining data retention.

Inventive Principle:

Principle #10Preliminary action

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 solution simplifies the writing process by eliminating the need for precise pulse width control, improving the success rate of writing operations and reducing the complexity of the writing process in magnetoresistive effect memory systems.

Implementation Method 1

a voltage-controlled magnetic anisotropy effect layer that is a magnetization free layer having a variable magnetization direction and has a voltage-controlled magnetic anisotropy effect

Methodology Applied

Scientific EffectVoltage-controlled magnetic anisotropy effect:

Implementation Method 2

Magnetoresistive effect memory according to the present disclosure includes: a magnetoresistive effect element

Methodology Applied

Scientific EffectMagnetoresistive effect: Magnetoresistance

Data Source

PatentUS20250006237A1Magnetoresistive effect memory, memory array, and memory system

Publication Date: 2025.01.02 SONY SEMICON SOLUTIONS CORP

AI summary

To achieve simplification of writing to magnetoresistive effect memory. The magnetoresistive effect memory includes a magnetoresistive effect element (120). The magnetoresistive effect element (120) provided in the magnetoresistive effect memory includes: a voltage-controlled magnetic anisotropy effect layer (first magnetization free layer 141) that is a magnetization free layer having a variable magnetization direction and has a voltage-controlled magnetic anisotropy effect; a non-voltage-controlled magnetic anisotropy effect layer (second magnetization free layer 143) that is a magnetization free layer having a variable magnetization direction and has no voltage-controlled magnetic anisotropy effect; and a magnetization fixed layer (122) that has a magnetic anisotropy and has an invariable magnetization direction.