Magnetic Device Oxide Layer Diffusion Barrier
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Solution Overview
Problem
Current magnetic devices with magnetoresistive effect elements face challenges in achieving high perpendicular magnetic anisotropy and magnetoresistive effects while preventing diffusion of magnetic materials during annealing processes.
Innovation Solution
Incorporating an oxide layer with a rare-earth element and a diffusivity adjusting element, where the covalent radius of the diffusivity adjusting element is smaller than that of the rare-earth element, to control impurity diffusion and promote crystallization of ferromagnetic layers, thereby maintaining high interface magnetic anisotropy and reducing parasitic resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an oxide layer with rare-earth element is used to promote crystallization of ferromagnetic layers, then interface magnetic anisotropy is improved, but magnetic materials may diffuse during annealing processes
Solution Approach 1:
A non-magnetic oxide layer is introduced as an intermediary between the magnetic layer and the substrate. This oxide layer serves as a diffusion barrier to prevent magnetic material diffusion during annealing while also promoting crystallization of the ferromagnetic layer to achieve high interface magnetic anisotropy. The oxide layer mediates between the conflicting requirements of preventing diffusion and promoting crystallization.
Solution Approach 2:
The patent uses a composite structure consisting of a magnetic layer and a non-magnetic oxide layer. The oxide layer contains specific elements (such as rare-earth elements like gadolinium or terbium, and diffusivity-adjusting elements like magnesium or aluminum) that work together to simultaneously prevent magnetic material diffusion and promote crystallization, achieving both objectives through material composition design.
2Ease of manufacture
If conventional oxide layers are used, then manufacturing is simpler, but parasitic resistance increases and magnetoresistive effect is reduced
Solution Approach 1:
The patent optimizes the compositional parameters of the oxide layer by incorporating specific rare-earth elements and diffusivity-adjusting elements in controlled ratios. This parameter optimization reduces parasitic resistance and enhances the magnetoresistive effect while maintaining manufacturability through standard sputtering or atomic layer deposition processes. The specific element composition and thickness are tuned to achieve the desired electrical properties.
3Manufacturing precision
If high-temperature annealing is applied to crystallize ferromagnetic layers, then magnetic anisotropy is improved, but magnetic materials diffuse excessively
Solution Approach 1:
The non-magnetic oxide layer acts as a mediator that enables high-temperature annealing to proceed without excessive magnetic material diffusion. It allows the thermal energy to effectively crystallize the ferromagnetic layer while the oxide layer itself serves as a diffusion barrier, permitting crystallization benefits without the harmful diffusion side effects.
Solution Approach 2:
The oxide layer has a thermal expansion coefficient matched to both the magnetic layer and substrate, allowing it to withstand high-temperature annealing cycles without creating excessive stress or defects. This thermal compatibility enables the annealing process to achieve thorough crystallization while the oxide layer maintains its integrity as a diffusion barrier throughout the thermal cycle.
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 enables high-quality crystallization of ferromagnetic layers, suppresses excessive write current, and enhances the magnetoresistive effect, making the magnetic device suitable for magnetic storage applications.
Implementation Method 1
suppresses diffusion of magnetic materials during annealing processes
Implementation Method 2
promote crystallization of ferromagnetic layers
Implementation Method 3
enhances the magnetoresistive effect
Implementation Method 4
maintaining high interface magnetic anisotropy
Data Source
AI summary
According to one embodiment, a magnetic device includes a magnetoresistive effect element including a first ferromagnet, a conductor, and an oxide provided between the first ferromagnet and the conductor, the oxide including a first oxide of a rare-earth element and a second oxide of an element of which a covalent radius is smaller than a covalent radius of the rare-earth element.