Lower-temperature crystallization of CoFeB in MgO magnetic tunnel junctions by using Ti capping layer
- Fujitsu Laboratories Limited, 10-1 Morinosato-Wakamiya, Atsugi 243-0197 (Japan)
Effects of capping materials on magnetoresistance (MR) properties of MgO magnetic tunnel junctions (MTJs) with a CoFeB free layer were investigated. MR ratios of samples with various capping materials showed a difference in annealing temperature dependence. MTJ with a Ti capping layer annealed at 270 deg. C showed a MR ratio 1.4 times greater than that with a conventional Ta or Ru capping layer. Secondary ion mass spectroscopy and high-resolution transmission electron microscopy images revealed that crystallization of CoFeB was remarkably affected by adjacent materials and the Ti capping layer adjoining CoFeB acted as a boron-absorption layer. These results suggest that the crystallization process can be controlled by choosing proper capping materials. Ti is one of the effective materials that accelerate the crystallization of CoFeB layers at lower annealing temperature.
- OSTI ID:
- 21175960
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 6 Vol. 94; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ABSORPTION
ANNEALING
BORON
BORON ALLOYS
COBALT ALLOYS
CRYSTALLIZATION
ION MICROPROBE ANALYSIS
IRON ALLOYS
LAYERS
MAGNESIUM OXIDES
MAGNETORESISTANCE
MASS SPECTRA
MASS SPECTROSCOPY
SUPERCONDUCTING JUNCTIONS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
TERNARY ALLOY SYSTEMS
TITANIUM
TRANSMISSION ELECTRON MICROSCOPY
TUNNEL EFFECT