Perpendicular MRAM with Segmented Insulating Films
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Solution Overview
Problem
Miniaturization of magnetoresistive random access memory (MRAM) devices is hindered by increased coercivity of magnetic storage layers as element size decreases, making it difficult to achieve both miniaturization and low current consumption, especially in magnetic field writing schemes, while spin-injection writing schemes face challenges with reduced spin-polarized electron injection at smaller volumes.
Innovation Solution
The implementation of a magnetic memory with a magnetoresistance effect element using a perpendicular magnetization film and a manufacturing method involving oxygen-based and nitrogen-based insulating films to reduce leak currents and enhance miniaturization, incorporating a spin injection write mode with a Buried Gate (BG) structure and specific layer formations to manage magnetization and current efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the element size is reduced to achieve miniaturization, then the integration density is improved, but the coercivity of the magnetic body increases and write current increases
Solution Approach 1:
The patent changes the magnetization direction parameter from in-plane to perpendicular magnetization. This parameter change enables the storage layer to maintain stable magnetization at smaller sizes with lower coercivity, allowing miniaturization without proportionally increasing write current when using spin-injection writing schemes
Solution Approach 2:
The patent replaces the magnetic field writing scheme with a spin-injection writing scheme. Instead of using external magnetic fields generated by write lines, the invention uses spin-polarized current injected directly into the storage layer to reverse magnetization, which is more efficient at smaller dimensions
2Reliability
If oxygen-based insulating film is used to reduce leak current, then reliability is improved, but nitrogen-based insulating film is needed additionally increasing device complexity
Solution Approach 1:
The patent segments the insulating film structure into two distinct layers: an oxygen-based insulating film layer and a nitrogen-based insulating film layer. Each layer performs a specific function - the oxygen-based layer provides excellent insulation properties to reduce leak current, while the nitrogen-based layer provides barrier properties. This segmentation allows each material to optimize its function without requiring a single complex material
Solution Approach 2:
The patent uses a composite insulating film structure combining oxygen-based and nitrogen-based insulating films. This composite structure leverages the complementary properties of both materials - the oxygen-based film's low leak current characteristics and the nitrogen-based film's barrier properties - achieving superior overall performance that neither material could provide alone
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 approach enables efficient miniaturization of MRAM devices with reduced write current and improved reliability by leveraging the spin injection write mode and optimized insulating film structures, effectively addressing the challenges of coercivity and current consumption.
Implementation Method 1
a magnetoresistance effect element (401) on the electrode
Implementation Method 2
another is a writing scheme (of spin-injection) using spin angular momentum transfer in which the magnetization direction of the storage layer is reversed by passing a spin-polarized current through the MTJ element itself
Data Source
AI summary
According to one embodiment, a magnetic memory is disclosed. The magnetic memory includes a substrate, an electrode provided on the substrate, a first insulating film surrounding a side surface of the electrode. The first insulating film contains oxygen. The magnetic memory further includes a second insulating film provided between the electrode and the first insulating film, and surrounding the side surface of the electrode. The second insulating film contains nitrogen. A magnetoresistance effect element is provided on the electrode.