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2002 Fiscal Year Final Research Report Summary

Trial Fabrication and Evaluation of Spin Tunnel Magnetoresistive Device

Research Project

Project/Area Number 13555001
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section展開研究
Research Field Applied materials science/Crystal engineering
Research InstitutionTohoku University

Principal Investigator

KUBOTA hitoshi  Tohoku University, Gradate School of Engineering, Research associate, 大学院・工学研究科, 助手 (30261605)

Co-Investigator(Kenkyū-buntansha) KUMAGAI Seiji  Sony, CNC DSC Magnetic Devices Division, Manager, CNC DSC磁気デバイス事業部, 課長(研究職)
MIYAZAKI Terunobu  Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (60101151)
ANDO Yasuo  Tohoku University, Graduate School of Engineering, Associate professor, 大学院・工学研究科, 助教授 (60250726)
NAKASHIO Eiji  Sony, CNC DSC Magnetic Devices Division, Researcher, CNC DSC磁気デバイス事業部, 研究員
Project Period (FY) 2001 – 2002
Keywordsfocused ion beam / carbon / tungsten / microfabrication / spin tunnel / magnetoresistance effect / epitaxial film / bias dependence
Research Abstract

Development of micro-fabrication processes of small magnetic tunnel junctions (MTJs) using focused ion beam induced deposition (FIBID) has been examined. FIBID technique was applied to make small carbon or tungsten patterns, those were used as Ar etching masks and/or electrical leads. The deposition tecnique has some advantages: Pattern location can be controlled freely and precisely, pattem shaps a easily designed, pattem height can be controlled widely, and sub-micron patterns should ha easily fabricated. The smallest lateral size of the carbon and tungsten mask patterns deposited were about 100 nm and 140 nm, repectively. The C mask patterns were hard for Ar etching and soft for O_2 ashing. Resistivity of the Wpatterns was enough small, thus, the W patterns can be used as electrical leads. MTJs were fabricated using C masks or W masks/leads. During Ar ion etching, redeposition at side walls of the mask patterns were formed, resulted in short-circuiting. It is necessary to avoid the redeposition to establish the fabrication process of small MTJs using FIBID technique.
To improve the quality of insulating layers in MTJs, we have used epitaxially grown Ag/Cu/Ni-Fe films on Si (111) substrates as bottom electrodes. Epitaxial growth of the trilayers was confirmed using X-ray diffraction and low energy electron diffraction. The MTJs fabricated showed large tunnel magnetoresistance (TMR) ratios of about 50%. The bias dependence of the TMR ratio was greatly improved in those MTJs. The insulating layers grown on the epitaxial bottom electrodes would have fewer defects than the those grown on textured bottom electrodes.
Further experiments are necessary to complete the fabrication process to apply to the MTJs with epitaxially grown bottom electrodes. The switching characteristics of epitaxially grown MTJs with an area of about 100 nm square would be investigated.

  • Research Products

    (38 results)

All Other

All Publications (38 results)

  • [Publications] 矢尾板和也: "プラズマ酸化法による低抵抗強磁性トンネル接合の作製"日本応用磁気学会誌. 25. 771-774 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Andrew C.C.Yu: "High resolution electron microscopy of Al-oxide barriers in magnetic tunnel junctions"Japanese Journal of Applied Physics. 40. 5058-5060 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Andrew C.C.Yu: "Direct observation of domain structure and magnetization reversal of magnetic thin films using Lorentz transmission electron microscopy"Japanese Journal of Applied Physics. 40. 4891-4895 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Andrew C.C.Yu: "Lorentz transmission electron microscopy and magnetic force microscopy characterization of NiFe/Al-oxide/Co films"Journal of Applied Physics. 91. 780-782 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Andrew C.C.Yu: "Microstructural and magnetic characteristics of IrMn exchange-biased tunnel junction"Journal of Magnetism and Magnetic Materials. 240. 130-133 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Andrew C.C.Yu: "Effect of Ti seed layer on the magnetization reversal process of Co/NiFe/Al-oxide/NiFe junction films"Journal of Applied Physics. 91. 5234-5239 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] X.F.Han: "A self-consistent calculation of intrinsic magnetoelectric properties in magnetic tunnel junctions"J. Magn. Magn. Mater.. 239. 167-169 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] X.F.Han: "Analysis of intricsic magnetoelectric properties in spin-valve-type tunnel junctions with high magnetoresutance and low resistance"Physical Review B. 63. 224404-4-224404-7 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] X.F.Han: "A self-consistent calculation and an Anisotropic Wavelength Cutoff Energy of Spin-wave Spectrum in Magnetic Tunnel junctions"J. Mater. Sci. Technol.. 17. 197-202 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H.Kubota: "Magnetoresistance and Dipole Shift of Ultrasmall Magnetic Tunnel Junctions Characterized by Conducting Atomic Force Microscopy"Japanese Journal of Applied Physics. 41. L180-L182 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Eiji Nakashio: "Longitudinal bias method using a long distance exchange coupling field in TMR junction"Journal of Applied Physics. 89. 7256-7358 (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Eiji Nakashio: "Flux guide type tunnel-valve head for tape storage applications"IEEE Transaction on Magnetics. 38. 1925-1927 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 井浦 聡則: "ラジカル酸化法で作製した高耐熱強磁性トンネル接合"日本応用磁気学会誌. 26. 839-842 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yasuo Ando: "Growth mechanism of thin insulating layer in ferromagnetic tunnel junctions prepared using various oxidation methods"Journal of Physics D. 35. 2415-2421 (2002)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Hitoshi Kubota: "Hard mask fabrication for MRAM elements using FIB assisted selective CVD"Journal of Applied Physics. 93. 8370-8372 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Ji Hyung Yu: "Magnetic tunnel junctions with high magnetoresistance and small bias voltage dependence using epitaxial NiFe(111) ferromagnetic bottom electrodes"Journal of Applied Physics. 93. 8555-8557 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yasuo Ando: "Interface characterization of magnetic tunnel junctions by using tunneling spectroscopy"Journal of Applied Physics. 93. 7023-7025 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 井浦 聡則: "下部磁性層を酸化して作製したトンネル接合の高耐熱特性"日本応用磁気学会誌. 27. 303-306 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 宮崎 照宣: "トンネル磁気抵抗効果とスピンエレクトロニクスの展開"固体物理. 38. 109-124 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] K. Yaoita: "Fabrication of low-resistance ferromagnetic tunnel junctions using plasma oxidation"J. Magn. Soc. Jpn.. 25. 771-774 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A. C. C. Yu: "High resolution electron microscopy of Al-oxide barriers in magnetic tunnel junctions"Japanese Journal of Applied Physics. 40. 5058-5060 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A. C. C. Yu: "Direct observation of domain structure and magnetization reversal of magnetic them using Lorentz transmission electron microscopy"Japanese Journal of Applied Physics. 40. 4891-4895 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A. C. C. Yu: "Lorentz transmission electron microscopy and magnetic force microscopy characterization of NiFe/Al-oxido/Co film"Journal of Applied Physics. 91. 780-782 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A. C. C. Yu: "Microstructural and magnetic characteristics of lrMn exchange-biased tunnel junction"Journal of Magnetism and Magnetic Materials. 240. 130-133 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] A. C. C. Yu: "Effect of Ti seed layer on the magnetization reversal process of Co/NiFe/Al-oxide/NiFe junction films"Journal of Applied Physics. 91. 5234-5239 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] X. F. Han: "A self-consistent calculation of intrinsic magnetoelectric properties in magnetic tunnel junctions"J. Magn. Magn. Mater.. 239. 167-169 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] X. F. Han: "Analysis of intrinsic magnetolectric in spin-vale-type tunnel junctions with high magnetoresistance and low resistance"Physical Review B63. 224404. 1-7 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] X. F. Han: "A self-consistent calculation and an Anisotropic wavelength cutoff energy of spin-wave spectrum in magnetic tunnel junctions"J. Mater. Sci. Technol.. 17. 197-202 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H. Kubota: "Magnetoresistance and Dipole Shift of Ultrasmall Magnetic Tunnel Junctions Characterized by Conducting Atomic Force Microscopy"Japanese Journal of Applied Physics. 41. L180-L182 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Eiji Nakashio: "Longitudinal bias method using a long distance exchange coupling field in TMR junction"Journal of Applied Physics. 89. 7356-7358 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Eiji Nakashio: "Flux guide type tunnel-valve head for tape storage applications"IEEE Transaction on Magnetics. 38. 1925-1927 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Iura: "Enhancement of thermal stability of ferromagnetic tunnel junctions prepared by the radical oxidation method"J. Magn. Soc. Jpn. 26. 839-842 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y. Ando: "Growth mechanism of thin insulating layer in ferromagnetic tunnel junctions prepared using various oxidation methods"Journal of Physics D. 35. 2415-2421 (2002)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H. Kubota: "Hand mask fabrication for MRAM elements using FIB assisted selective CVD"Journal of Applied Physics. 93. 8370-8372 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] J. H. Yu: "Magnetic tunnel junctions with high magnetoresistance and small bias voltage dependence using epitaxial NiFe(111) ferromagnetic spectroscopy"Journal of Applied Physics. 93. 8555-8557 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y. Ando: "Interface characterization of magnetic tunnel junctions by using tunneling spectroscopy"Journal of Applied Physics. 93. 7023-7025 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Iura: "Thermal stability of tunnel junctions with additional oxidation at the interface of the bottom electrode"J. Magn. Soc. Jpan.. 27. 303-306 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T. Miyazaki: "Tunnel magnetoresistance effect and development of spinelectronics"Solid State Physics. 38. 109-124 (2003)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2004-04-14  

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