Magnetic Memory Capping Pattern for Etching Protection
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Solution Overview
Problem
Magnetic memory devices face challenges in achieving high integration and low power consumption while maintaining improved electrical and magnetic properties, particularly in the design of magnetic tunnel junctions where etching processes can lead to electrical shorts and deterioration of magnetic properties.
Innovation Solution
The magnetic memory device incorporates a capping pattern with different non-magnetic metals, including a first and second non-magnetic pattern with high oxidation potentials, which form a protection layer on the lateral surface of the magnetic tunnel junction during etching, preventing electrical shorts and maintaining magnetic anisotropy, and includes a specific structure with a pinned and free magnetic pattern stacked on a substrate with a tunnel barrier and electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional capping pattern is used in magnetic tunnel junction fabrication, then the manufacturing process is simple, but electrical shorts occur and magnetic properties deteriorate during etching
Solution Approach 1:
The capping pattern is divided into multiple segments: a first capping pattern layer, a first non-magnetic pattern layer, and a second non-magnetic pattern layer. Each layer serves a specific function in preventing electrical shorts and maintaining magnetic properties during the etching process, thereby resolving the contradiction between reliability and structural complexity.
Solution Approach 2:
The first and second non-magnetic pattern layers act as intermediary layers between the magnetic tunnel junction and the capping pattern. These intermediary layers prevent direct contact between etching solutions and the magnetic structures, thereby preventing electrical shorts and magnetic property deterioration while adding necessary structural complexity.
2Stability of the object's composition
If high oxidation potential metals are used in the capping pattern, then magnetic anisotropy is maintained during etching, but the manufacturing process becomes more complex
Solution Approach 1:
The oxidation potential parameter is changed by selecting specific metals (such as Pt, Ir, or Au) for the non-magnetic pattern layers. These metals have high oxidation potentials that prevent oxidation of the magnetic tunnel junction during etching, thereby maintaining magnetic anisotropy. The parameter change introduces manufacturing complexity but ensures stability of magnetic properties.
3Productivity
If the magnetic tunnel junction is made smaller for high integration, then device density increases, but electrical shorts become more likely during etching
Solution Approach 1:
The protection against electrical shorts is extended from the top view to the lateral dimension by adding the first and second non-magnetic pattern layers that extend along the lateral surface of the magnetic tunnel junction. This dimensional extension provides protection even when the junction size is reduced for high integration, thereby maintaining reliability without sacrificing productivity.
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 enhances the electrical and magnetic properties of the magnetic memory device, preventing electrical shorts and maintaining magnetic anisotropy, thus improving the device's performance in terms of integration and power consumption.
Implementation Method 1
The first non-magnetic pattern and the second non-magnetic pattern may include different metals from each other. The protection layer may include metal oxide that contains at least one selected from the first metal and the second metal.
Data Source
AI summary
Disclosed is a magnetic memory device including a pinned magnetic pattern and a free magnetic pattern that are sequentially stacked on a substrate, a tunnel barrier pattern between the pinned magnetic pattern and the free magnetic pattern, a top electrode on the free magnetic pattern, and a capping pattern between the free magnetic pattern and the top electrode. The capping pattern includes a lower capping pattern, an upper capping pattern between the lower capping pattern and the top electrode, a first non-magnetic pattern between the lower capping pattern and the upper capping pattern, and a second non-magnetic pattern between the first non-magnetic pattern and the upper capping pattern. Each of the lower capping pattern and the upper capping pattern includes a non-magnetic metal. The first non-magnetic pattern and the second non-magnetic pattern include different metals from each other.