CoFeB Sputtering Target Material Phase Control
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Solution Overview
Problem
The existing sputtering target materials for CoFeB thin films in magnetic tunneling junctions generate particles during sputtering, affecting the yield of the sputtering film.
Innovation Solution
A sputtering target material with a balanced composition of Co, Fe, and unavoidable impurities, where the intensity ratios of specific boride phases (CoFe)3B, Co3B, and Fe3B to their respective stable forms are controlled to 1.50 or less, reducing particle generation by removing unstable boride phases through rapid solidification and gas atomization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rapidly solidified structure of atomized powder is used as sputtering target material, then the sputtering process can be performed, but particles are generated during sputtering
Solution Approach 1:
The invention extracts and removes the harmful (CoFe)3B, Co3B, and Fe3B boride phases from the sputtering target material through controlled composition design. By specifying precise compositional ranges and controlling the intensity ratios of these phases in XRD patterns, the harmful phases are eliminated while maintaining the rapidly solidified structure necessary for sputtering processability.
Solution Approach 2:
The invention changes the compositional parameters of the sputtering target material by defining specific ranges for Co, Fe, and B content, and by controlling the intensity ratios of boride phases. This parameter optimization eliminates particle-generating phases while preserving the rapidly solidified structure that enables successful sputtering.
2Ease of manufacture
If (CoFe)3B, Co3B, or Fe3B phases are present in the sputtering target material, then the material can be formed, but particle generation occurs during sputtering
Solution Approach 1:
The invention specifically targets and removes the harmful (CoFe)3B, Co3B, and Fe3B phases by controlling the compositional parameters and monitoring the intensity ratios in XRD patterns. This selective extraction eliminates particle generation while maintaining the ability to form the sputtering target material.
Solution Approach 2:
By defining precise compositional ranges and controlling the intensity ratios of boride phases to 1.50 or less, the invention changes the material parameters to eliminate harmful phases. This parameter control achieves both target material formation and particle suppression.
3Stability of the object's composition
If the intensity ratio of (CoFe)3B/(CoFe)2B or Co3B/Co2B or Fe3B/Fe2B is high, then unstable boride phases are present, but particle generation increases
Solution Approach 1:
The invention optimizes the compositional parameters and controls the intensity ratios of boride phases to 1.50 or less. This parameter control stabilizes the composition by suppressing unstable phases that generate particles, while maintaining the desired sputtering target material properties.
Solution Approach 2:
The invention uses XRD intensity ratio measurement as a feedback mechanism to monitor and control the presence of unstable boride phases. By setting the intensity ratio threshold at 1.50 or less, the process ensures stable composition and minimizes particle generation during sputtering.
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 significantly reduces particle formation during sputtering, thereby improving the product yield of the sputtering film by adjusting the boron content to 10-50% and controlling the X-ray diffraction intensity ratios, ensuring the formation of stable compounds.
Implementation Method 1
A CoFeB thin film of a magnetic tunneling junction (MTJ) element is formed by sputtering a CoFeB target
Implementation Method 2
the intensity ratio [I [(CoFe)3B]/I [(CoFe)2B]] of the X-ray diffraction intensity [I [(CoFe)3B]] of (CoFe)3B (121) to the X-ray diffraction intensity [I [(CoFe)2B]] of (CoFe)2B (200)
Data Source
AI summary
An object of the present invention is to reduce particles generated in sputtering, and in order to achieve such an object, there is provided a sputtering target material including in at. %: 10 to 50% of B; and the balance of at least one of Co and Fe, and unavoidable impurities, in which the intensity ratio [I [(CoFe)3B]/I [(CoFe)2B]] of the X-ray diffraction intensity [I [(CoFe)3B]] of (CoFe)3B (121) to the X-ray diffraction intensity [I [(CoFe)2B]] of (CoFe)2B (200), the intensity ratio [I (Co3B)/I (Co2B)] of the X-ray diffraction intensity [I (Co3B)] of Co3B (121) to the X-ray diffraction intensity [I (Co2B)] of Co2B (200), or the intensity ratio [I (Fe3B)/I (Fe2B)] of the X-ray diffraction intensity [I (Fe3B)] of Fe3B (121) to the X-ray diffraction intensity [I (Fe2B)] of Fe2B (200) is 1.50 or less.