CoFeSiB Pd Multilayer Thin Films for High Temperature Magnetic Stability
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Solution Overview
Problem
Conventional magnetic multilayer thin films lose perpendicular magnetic anisotropy at high temperatures, making them unsuitable for high-temperature semiconductor processes, and there is a need for materials that maintain stability and magnetic properties after annealing at temperatures above 400 degrees Celsius.
Innovation Solution
The formation of CoFeSiB/Pd or CoSiB/Pd multilayer thin films using alternating sputter-deposition, with specific composition ratios and layer structures, which are then annealed at temperatures up to 500 degrees Celsius, maintaining perpendicular magnetic anisotropy and magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional magnetic multilayer thin films are used, then perpendicular magnetic anisotropy can be achieved at low temperatures, but the magnetic properties are lost after high-temperature annealing above 400 degrees Celsius
Solution Approach 1:
The patent uses a composite multilayer structure consisting of CoFeSiB/Pd or CoSiB/Pd layers. The CoFeSiB or CoSiB layer provides perpendicular magnetic anisotropy, while the Pd layer enhances thermal stability. This composite structure maintains perpendicular magnetic anisotropy even after high-temperature annealing above 400°C, resolving the contradiction between temperature resistance and magnetic property stability.
Solution Approach 2:
The patent optimizes specific parameters including the thickness of each layer (CoFeSiB/Pd or CoSiB/Pd with total thickness 5-20 nm), composition ratios (Co:Fe:Si:B in specific proportions), and annealing conditions. By carefully controlling these parameters, the material maintains perpendicular magnetic anisotropy after high-temperature annealing, achieving both high temperature resistance and magnetic stability.
2Stability of the object's composition
If high-temperature annealing is performed to improve material stability, then structural stability is enhanced, but perpendicular magnetic anisotropy is lost
Solution Approach 1:
The multilayer composite structure of CoFeSiB/Pd or CoSiB/Pd is designed so that the Pd layer provides thermal stability during annealing while the CoFeSiB or CoSiB layer maintains perpendicular magnetic anisotropy. The interface between these layers creates a stable structure that withstands high-temperature annealing without losing magnetic properties.
Solution Approach 2:
Different regions of the multilayer structure have different functions: the CoFeSiB or CoSiB layers are optimized for magnetic properties with specific thickness and composition, while the Pd layers are optimized for thermal stability. This local optimization allows the overall structure to maintain both material stability and perpendicular magnetic anisotropy after high-temperature annealing.
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 CoFeSiB/Pd or CoSiB/Pd multilayer thin films exhibit stable perpendicular magnetic anisotropy and high coercivity even after high-temperature annealing, making them suitable for use in magnetic tunnel junctions and magnetic memory devices.
Implementation Method 1
The formation of CoFeSiB/Pd or CoSiB/Pd multilayer thin films using alternating sputter-deposition
Implementation Method 2
which are then annealed at temperatures up to 500 degrees Celsius, maintaining perpendicular magnetic anisotropy and magnetic properties
Data Source
AI summary
A method for forming a multilayer thin film exhibiting perpendicular magnetic anisotropy includes alternately sputtering a CoFeSiB target and a Pd target inside a vacuum chamber to form a [CoFeSiB/Pd] multilayer thin film on a substrate disposed inside the vacuum chamber. The number of times the [CoFeSiB/Pd] multilayer thin film is stacked may be 3 or more.