Repair effect on patterned CoFeB-based magnetic tunneling junction using rapid thermal annealing

Wu, Kaijie; Wang, Yung Hung; Chen, Wei Chuan; Yang, Shan-Yi; Shen, Kuei Hung; Kao, Mu‐Jung; Tsai, M. J.; Kuo, Chao‐Yin; Wu, Jong-Ching; Horng, Lance

doi:10.1016/j.jmmm.2006.10.605

Cited by 3 publications

(2 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Magnetic tunneling junctions (MTJs) have a sandwiched structure, which is composed of a top ferromagnetic (FM1) layer, an insulating tunneling layer (spacer), and a bottom ferromagnetic (FM2) layer, which can be utilized in high-density read/write heads, magnetoresistance random access memories (MRAM) and gauge sensor applications. This structure yields a very large magnetoresistance (MR) owing to spin-dependent tunneling effect [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. Numerous factors influence the magnetoresistance, such as the indirect spin exchange-coupling of ferromagnetic layers, and the quality of the insulating tunneling layer, which affect the magnetic performance.…”

Section: Introductionmentioning

confidence: 99%

Susceptibility of CoFeB/AlOx/Co Magnetic Tunnel Junctions to Low-Frequency Alternating Current

Chen

Chang

2013

Nanomaterials

View full text Add to dashboard Cite

This investigation studies CoFeB/AlOx/Co magnetic tunneling junction (MTJ) in the magnetic field of a low-frequency alternating current, for various thicknesses of the barrier layer AlOx. The low-frequency alternate-current magnetic susceptibility (χac) and phase angle (θ) of the CoFeB/AlOx/Co MTJ are determined using an χac analyzer. The driving frequency ranges from 10 to 25,000 Hz. These multilayered MTJs are deposited on a silicon substrate using a DC and RF magnetron sputtering system. Barrier layer thicknesses are 22, 26, and 30 Å. The X-ray diffraction patterns (XRD) include a main peak at 2θ = 44.7° from hexagonal close-packed (HCP) Co with a highly (0002) textured structure, with AlOx and CoFeB as amorphous phases. The full width at half maximum (FWHM) of the Co(0002) peak, decreases as the AlOx thickness increases; revealing that the Co layer becomes more crystalline with increasing thickness. χac result demonstrates that the optimal resonance frequency (fres) that maximizes the χac value is 500 Hz. As the frequency increases to 1000 Hz, the susceptibility decreases rapidly. However, when the frequency increases over 1000 Hz, the susceptibility sharply declines, and almost closes to zero. The experimental results reveal that the mean optimal susceptibility is 1.87 at an AlOx barrier layer thickness of 30 Å because the Co(0002) texture induces magneto-anisotropy, which improves the indirect CoFeB and Co spin exchange-coupling strength and the χac value. The results concerning magnetism indicate that the magnetic characteristics are related to the crystallinity of Co.

show abstract

Section: Introductionmentioning

confidence: 99%

Susceptibility of CoFeB/AlOx/Co Magnetic Tunnel Junctions to Low-Frequency Alternating Current

Chen

Chang

2013

Nanomaterials

View full text Add to dashboard Cite

show abstract

“…The amorphous CoFeB free layer of MTJ can induce a high tunneling magnetoresistance (TMR) ratio at RT [6]. Furthermore, the amorphous CoFeB free layer of MTJ can enhance a significantly higher TMR ratio during postannealing T A = 150 • C treatment [7][8][9]. The contact angle and surface energy properties, such as amorphous, noncrystalline, and crystalline status, are associated with the crystalline degree of thin film [10,11].…”

Section: Introductionmentioning

confidence: 99%

Determining Contact Angle and Surface Energy of Co₆₀Fe₂₀B₂₀Thin Films by Magnetron Sputtering

Wang

Chen

2011

Journal of Nanomaterials

View full text Add to dashboard Cite

This study examined the deposition of CoFeB thin films on a glass substrate at room temperature (RT), as well as the effects of conducting postannealing at heat annealingTA=150°C for 1 h. The thickness (tf) of the CoFeB thin films ranged from 100 Å to 500 Å. The microstructure, average contact angle, and surface energy properties were also investigated. X-ray diffraction (XRD) revealed that CoFeB films are nanocrystalline at RT and that post-annealing treatment increases in conjunction with the crystallinity. The surface energy of the CoFeB thin films is related to adhesive strength. The CoFeB films form a contact angle of larger than90∘with water as a test liquid. This finding demonstrates that the CoFeB film is hydrophobic. Astfincreases from 100 Å to 500 Å, the surface energy at RT decreases from 40 mJ/mm2to 32 mJ/mm2. During post-annealing treatment, the surface energy increases from 32 mJ/mm2to 35 mJ/mm2, astfincreases from 100 Å to 300 Å; then it decreases to 31 mJ/mm2, astfincreases from 300 Å to 500 Å. The surface energy of the as-deposited CoFeB thin films exceeds that during post-annealing treatment at thicknesses of 100 Å and 200 Å, suggesting that as-deposited CoFeB thin film increases the adhesion.

show abstract

Crystallization and grain growth behavior of CoFeB and MgO layers in multilayer magnetic tunnel junctions

Mukherjee

Bai

MacMahon

et al. 2009

Journal of Applied Physics

View full text Add to dashboard Cite

The relationship between crystallization, grain growth behavior, and the diffusion of B out of CoFeB has been investigated in annealed film stacks of sputtered CoFeB∣MgO using a combination of two dimensional x-ray diffraction, transmission electron microscopy, and parallel electron energy loss spectroscopy (PEELS). The analysis shows grain growth in MgO layers. It shows crystallization at approximately 350°C, and subsequent grain growth in CoFeB layers with annealing. The orientations of the grains of MgO and CoFe are definitively shown to be (002) in the out-of-plane direction. The MgO lattice is seen to have an in-plane tensile stress, while CoFe lattice is shown to have an in-plane compressive stress. CoFe grains are observed to be smaller than MgO grains, rather than being of equal size as previously understood. The physical process of B diffusion into MgO has also been investigated using PEELS and is determined that the diffusion of B through MgO is mediated through vacancies and defect states by the formation of BOx complexes.

show abstract

Repair effect on patterned CoFeB-based magnetic tunneling junction using rapid thermal annealing

Cited by 3 publications

References 8 publications

Susceptibility of CoFeB/AlOx/Co Magnetic Tunnel Junctions to Low-Frequency Alternating Current

Susceptibility of CoFeB/AlOx/Co Magnetic Tunnel Junctions to Low-Frequency Alternating Current

Determining Contact Angle and Surface Energy of Co₆₀Fe₂₀B₂₀Thin Films by Magnetron Sputtering

Crystallization and grain growth behavior of CoFeB and MgO layers in multilayer magnetic tunnel junctions

Contact Info

Product

Resources

About

Repair effect on patterned CoFeB-based magnetic tunneling junction using rapid thermal annealing

Cited by 3 publications

References 8 publications

Susceptibility of CoFeB/AlOx/Co Magnetic Tunnel Junctions to Low-Frequency Alternating Current

Susceptibility of CoFeB/AlOx/Co Magnetic Tunnel Junctions to Low-Frequency Alternating Current

Determining Contact Angle and Surface Energy of Co60Fe20B20Thin Films by Magnetron Sputtering

Crystallization and grain growth behavior of CoFeB and MgO layers in multilayer magnetic tunnel junctions

Contact Info

Product

Resources

About

Determining Contact Angle and Surface Energy of Co₆₀Fe₂₀B₂₀Thin Films by Magnetron Sputtering