CoFeB MRAM Capping Layer for Thermal Stability
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Solution Overview
Problem
Current magnetic random access memory (MRAM) devices with CoFeB/MgO structures face limitations in saturation magnetization, perpendicular anisotropy, and thermal stability, particularly due to high temperature processing that can destroy perpendicular anisotropy, hindering their application in high-density storage and thermal endurance.
Innovation Solution
A magnetic electronic device and manufacturing method involving a substrate, buffer layer, CoFeB layer, metal oxidation layer, and capping layer, where the capping layer absorbs diffusing oxygen and boron atoms through rapid thermal annealing, enhancing saturation magnetization and perpendicular anisotropy, and improving thermal stability of the CoFeB layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If high temperature processing is applied to CoFeB/MgO structures, then manufacturing process is simplified, but perpendicular anisotropy is destroyed and thermal stability deteriorates
Solution Approach 1:
A capping layer is formed on the CoFeB layer before high temperature processing to preemptively protect the perpendicular anisotropy. The capping layer acts as a barrier that prevents thermal degradation during subsequent manufacturing processes, allowing high temperature processing to proceed without destroying the magnetic properties
Solution Approach 2:
The capping layer serves as an intermediary between the CoFeB layer and the high temperature environment. It mediates the thermal stress and prevents direct thermal damage to the CoFeB/MgO interface, thereby preserving perpendicular anisotropy while enabling simplified high temperature manufacturing processes
2Quantity of substance
If CoFeB layer thickness is increased to improve signal, then saturation magnetization increases, but perpendicular anisotropy is reduced and thermal stability decreases
Solution Approach 1:
The invention changes the protective parameter by introducing a capping layer with specific thickness and material properties. This parameter change allows the CoFeB layer to maintain optimal thickness for saturation magnetization while the capping layer compensates for any loss in perpendicular anisotropy through its protective effect during thermal processing
3Ease of manufacture
If conventional CoFeB/MgO structure is used, then manufacturing is easier, but thermal stability factor remains below required value for long-term storage
Solution Approach 1:
The invention creates a composite structure by adding a capping layer to the conventional CoFeB/MgO structure. This composite material approach maintains the ease of manufacturing the base structure while the additional capping layer component provides the necessary thermal stability enhancement for long-term storage reliability
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 method significantly increases saturation magnetization and perpendicular anisotropy, achieving thermal stability and endurance suitable for long-term storage applications, with saturation magnetization reaching 1500 emu/cc and anisotropy field up to 4000 Oe, while maintaining thermal endurance across varying capping layer thicknesses.
Implementation Method 1
the capping layer absorbs diffusing oxygen and boron atoms through rapid thermal annealing
Implementation Method 2
the capping layer absorbs diffusing oxygen and boron atoms
Implementation Method 3
the data bit is stored by different relative magnetization alignment of the recording layer (free layer) and the reference layer (pinned layer), where parallel and anti-parallel magnetization alignment can result in low resistance level and high resistance level due to magnetoresistance (MR) effect
Implementation Method 4
After the as-grown amorphous CoFeB experiences an annealing treatment, a good texturing (001) can be generated at the interface of CoFeB and MgO
Implementation Method 5
CoFeB/MgO with perpendicular magnetic anisotropy
Data Source
AI summary
A magnetic electronic device comprises a substrate, a first buffer layer, a first CoFeB layer, a first metal oxidation layer, a second buffer and a capping layer. The first buffer layer is disposed on the substrate. The first CoFeB layer is disposed on the first buffer layer. The first metal oxidation layer is disposed on the first CoFeB layer. The second buffer is disposed on the first metal oxidation layer, and the material of the second buffer layer includes platinum, palladium, tantalum or their any combination. The capping layer disposed on the second buffer. A manufacturing method of the magnetic electronic device is also disclosed.