Magnetic Memory Storage Node Cap Structure Design

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Solution Overview

Problem

Magnetic memory devices face challenges in integration due to the need for separate wiring to generate external magnetic fields, which hinders increased integration and efficiency, especially in spin transfer torque MRAM (STT-MRAM) devices.

Innovation Solution

The development of storage nodes with a free magnetic layer that has a cap structure and is switchable by a spin current, using in-plane or perpendicular magnetic anisotropy materials, allowing for higher integration and reduced refresh rates, enabling more compact and efficient magnetic memory devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If traditional DRAM structure is used, then the device can be manufactured with existing processes, but the standby power consumption is high due to frequent refresh requirements

Engineering Contradiction:

Improvestandby power consumptionVSAvoidrefresh cycle

Core Design Contradiction:

Use of energy by stationary objectVSDuration of action of stationary object

Solution Approach 1:

The patent utilizes magnetic phase transitions and magnetic anisotropy (in-plane or perpendicular) in the free magnetic layer to maintain stable magnetization states without continuous power supply, enabling non-volatile or low-power volatile memory operation with extended refresh cycles

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The storage node employs composite magnetic layer structures including pinned layer, tunnel barrier layer, and free magnetic layer with specific magnetic anisotropy materials, combining multiple material properties to achieve stable magnetization states that reduce refresh requirements and standby power consumption

Inventive Principle:

Principle #40Composite materials

2Reliability

If the free magnetic layer is formed without a cap structure, then the manufacturing process is simpler, but the magnetization direction cannot be effectively switched by spin current

Engineering Contradiction:

Improvemagnetization switchingVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies cap structures selectively to specific material layers in the storage node (such as the free magnetic layer or underlying layers) to locally enhance magnetic anisotropy and spin transfer torque effects, improving magnetization switching reliability without unnecessarily complicating the entire structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Inventive Principle:

Principle #40Composite materials

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 enables higher integration and longer refresh cycles, reducing standby power consumption and achieving more compact magnetic memory devices with improved performance compared to traditional DRAMs.

Implementation Method 1

a free magnetic layer formed on the tunnel barrier layer and in which a magnetization direction is switched by a spin current

Methodology Applied

Scientific EffectSpin transfer torque:

Implementation Method 2

a magnetic random access memory (MRAM) having a tunneling magnetoresistance (TMR) effect

Methodology Applied

Scientific EffectTunneling magnetoresistance (TMR) effect:

Data Source

PatentUS8803266B2Storage nodes, magnetic memory devices, and methods of manufacturing the same

Publication Date: 2014.08.12 SAMSUNG ELECTRONICS CO LTD

AI summary

A storage node of a magnetic memory device includes: a lower magnetic layer, a tunnel barrier layer formed on the lower magnetic layer, and a free magnetic layer formed on the tunnel barrier. The free magnetic layer has a magnetization direction that is switchable in response to a spin current. The free magnetic layer has a cap structure surrounding at least one material layer on which the free magnetic layer is formed.