J. Mater. Sci. Technol. ›› 2007, Vol. 23 ›› Issue (03): 304-306.

• 论文 • 上一篇    下一篇

A Novel Design and Fabrication of Magnetic Random Access Memory Based on Nano-ring-type Magnetic TunnelJunctions

韩秀峰   

  1. 中国科学院物理研究所磁学国家重点实验室MO2组
  • 收稿日期:2007-03-09 修回日期:1900-01-01 出版日期:2007-05-28 发布日期:2009-10-10
  • 通讯作者: 韩秀峰

A Novel Design and Fabrication of Magnetic Random Access Memory Based on Nano-ring-type Magnetic TunnelJunctions

X.F.Han, H.X.Wei, Z.L.Peng, H.D.Yang, J.F.Feng, G.X.Du, Z.B.Sun, L.X.Jiang, Q.H.Qin, M.Ma, Y.Wang, Z.C.Wen, D.P.Liu, W.S.Zhan   

  1. State Key Laboratory of Magnetism, BeijingNational Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing 100080, China
  • Received:2007-03-09 Revised:1900-01-01 Online:2007-05-28 Published:2009-10-10
  • Contact: X.F.Han

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摘要： Nano-ring-type magnetic tunnel junctions (NR-MTJs) with the layer structure of Ta(5)/Ir22Mn78(10)/Co75Fe25(2)/Ru(0.75)/Co60Fe20B20(3)/Al(0.6)-oxide/Co60Fe20B20(2.5)/Ta(3)/ Ru(5) (thickness unit: nm) were nano-fabricated on the Si(100)/SiO2 substrate using magnetron sputtering deposition combined with the optical lithography, electron beam lithography (EBL) and Ar ion-beam etching techniques. The smaller NR-MTJs with the outer- and inner-diameter of around 100 and 50 nm and also their corresponding NR-MTJ 4x4 arrays were nano-patterned. The tunneling magnetoresistance (TMR & R) versus driving current (I) loops for a spin-polarized current switching were measured, and the TMR ratio of around 20% at room temperature were observed. The critical values of switching current for the free Co60Fe20B20 layer relative to the reference Co60Fe20B20 layer between parallel (clockwise) and anti-parallel (anti-clockwise) magnetization states were between 0.50 and 0.65 mA in such NR-MTJs. It is suggested that the applicable MRAM fabrication with the density and capacity higher than 256 Mbite/inch2 even 6 Gbite/inch2 are possible using both 1 NR-MTJ + 1 transistor structure and current switching mechanism based on this experimental results based on our fabricated 4x4 MRAM Demo devices.

Abstract: Nano-ring-type magnetic tunnel junctions (NR-MTJs) with the layer structure of Ta(5)/Ir22Mn78(10)/Co75Fe25(2)/Ru(0.75)/Co60Fe20B20(3)/Al(0.6)-oxide/Co60Fe20B20(2.5)/Ta(3)/Ru(5) (thickness unit: nm) were nano-fabricated on the Si(100)/SiO2 substrate using magnetron sputtering deposition combined with the optical lithography, electron beam lithography (EBL) and Ar ion-beam etching techniques. The smaller NR-MTJs with the inner- and outer-diameter of around 50 and 100 nm and also their corresponding NR-MTJ arrays were nano-patterned. The tunneling magnetoresistance (TMR & R) versus driving current (I) loops for a spin-polarized current switching were measured, and the TMR ratio of around 35% at room temperature were observed. The critical values of switching current for the free Co60Fe20B20 layer relative to the reference Co60Fe20B20 layer between parallel and anti-parallel magnetization states were between 0.50 and 0.75 mA in such NR-MTJs. It is suggested that the applicable MRAM fabrication with the density and capacity higher than 256 Mbit/inch2 even 6 Gbite/inch2 are possible using both 1 NR-MTJ+1 transistor structure and current switching mechanism based on based on our fabricated 4×4 MRAM demo devices.

Key words: Nano-ring-type magnetic tunnel junctions, NR-MTJ, MRAM, spin polarization, Spin transfer effect