Magnetic Memory HfB Cap Layer to Reduce Short Circuits

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Solution Overview

Problem

Existing magnetic memory devices face challenges in reducing defect occurrence rates and improving performance, particularly with miniaturization and high-density memory cell arrangements, due to issues with short circuits between storage and reference layers in magnetoresistance effect elements.

Innovation Solution

Incorporating a metal cap layer containing hafnium boride (HfB) or hafnium (Hf) above the storage layer in the magnetic memory device configuration, which reduces the defect occurrence rate by enhancing the etching resistance and improving the structural integrity of the magnetoresistance effect elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional metal cap layer is used in high-density memory cell arrangements, then device complexity is reduced, but the defect occurrence rate increases due to short circuits between storage and reference layers

Engineering Contradiction:

Improvedefect occurrence rateVSAvoidlayer structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the metal cap layer into multiple distinct layers: a first metal cap layer containing hafnium boride (HfB) or hafnium (Hf) and a second metal cap layer containing ruthenium (Ru), platinum (Pt), or palladium (Pd). This segmentation allows each layer to perform specific functions - the Hf-containing layer provides etching resistance to prevent short circuits, while the Ru/Pt/Pd-containing layer provides magnetic shielding and structural stability, thereby reducing defect occurrence rates in high-density memory cell arrangements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite material structures by combining different metal layers with distinct properties. The first metal cap layer uses hafnium boride or hafnium compounds for high etching resistance, while the second metal cap layer uses ruthenium, platinum, or palladium for magnetic shielding and structural integrity. This composite approach optimizes both reliability and performance by leveraging the complementary strengths of different materials.

Inventive Principle:

Principle #40Composite materials

2Productivity

If miniaturization is pursued to increase memory density, then productivity increases, but manufacturing precision becomes more difficult to maintain due to increased risk of short circuits

Engineering Contradiction:

Improvememory densityVSAvoidlayer separation precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary protective action by incorporating the first metal cap layer containing hafnium boride or hafnium during the manufacturing process. This layer is formed in advance to provide etching resistance that prevents short circuits between the storage layer and reference layer, thereby maintaining manufacturing precision even as memory cells are miniaturized to increase density.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If the metal cap layer is simplified to reduce device complexity, then ease of manufacture improves, but reliability deteriorates due to increased short circuit failures

Engineering Contradiction:

Improvelayer deposition simplicityVSAvoidshort circuit failure rate

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent segments the metal cap layer into functionally distinct layers to simultaneously achieve ease of manufacture and high reliability. The first layer (Hf-containing) addresses etching resistance to prevent short circuits, while the second layer (Ru/Pt/Pd-containing) provides magnetic shielding. This segmentation allows each layer to be optimized for its specific function while maintaining overall manufacturing efficiency.

Inventive Principle:

Principle #1Segmentation

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 implementation of a hafnium boride-containing metal cap layer significantly reduces the short circuit failure rate, thereby enhancing the reliability and performance of high-density memory cell arrangements in magnetic memory devices.

Implementation Method 1

a magnetic memory device that uses a magnetoresistance effect element as a memory element

Methodology Applied

Scientific EffectMagnetoresistance effect: Magnetoresistance

Implementation Method 2

Methodology Applied

Scientific EffectEtching resistance:

Data Source

PatentUS20250295041A1Magnetic memory device

Publication Date: 2025.09.18 KIOXIA CORP

AI summary

According to one embodiment, a magnetic memory device includes first, second, third, fourth, fifth, sixth and seventh non-magnetic layers, and first, second and third ferromagnetic layers. The first ferromagnetic layer, the second non-magnetic layer, the second ferromagnetic layer, the third non-magnetic layer, the third ferromagnetic layer, the fourth non-magnetic layer, the fifth non-magnetic layer, the sixth non-magnetic layer, and the seventh non-magnetic layer are provided in this order above the first non-magnetic layer. The first non-magnetic layer includes silicon. The fourth non-magnetic layer includes magnesium and oxygen. The fifth non-magnetic layer includes molybdenum. The sixth non-magnetic layer includes hafnium. The seventh non-magnetic layer includes ruthenium.