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Magnetic tunnel junction device

外国特許コード F170009043
整理番号 K02012US6
掲載日 2017年4月26日
出願国 アメリカ合衆国
出願番号 201514837558
公報番号 20160020385
公報番号 9608198
出願日 平成27年8月27日(2015.8.27)
公報発行日 平成28年1月21日(2016.1.21)
公報発行日 平成29年3月28日(2017.3.28)
国際出願番号 JP2005004720
国際公開番号 WO2005088745
国際出願日 平成17年3月10日(2005.3.10)
国際公開日 平成17年9月22日(2005.9.22)
優先権データ
  • 特願2004-071186 (2004.3.12) JP
  • 特願2004-313350 (2004.10.28) JP
  • 2005US-10591947 (2005.3.10) US
  • 2005WO-JP04720 (2005.3.10) WO
  • 2010US-12923643 (2010.9.30) US
  • 2012US-13400340 (2012.2.20) US
  • 2013US-13767290 (2013.2.14) US
発明の名称 (英語) Magnetic tunnel junction device
発明の概要(英語) (US9608198)
The output voltage of an MRAM is increased by means of an Fe(001)/MgO(001)/Fe(001) MTJ device, which is formed by microfabrication of a sample prepared as follows: A single-crystalline MgO (001) substrate is prepared.
An epitaxial Fe(001) lower electrode (a first electrode) is grown on a MgO(001) seed layer at room temperature, followed by annealing under ultrahigh vacuum.
A MgO(001) barrier layer is epitaxially formed on the Fe(001) lower electrode (the first electrode) at room temperature, using a MgO electron-beam evaporation.
A Fe(001) upper electrode (a second electrode) is then formed on the MgO(001) barrier layer at room temperature.
This is successively followed by the deposition of a Co layer on the Fe(001) upper electrode (the second electrode).
The Co layer is provided so as to increase the coercive force of the upper electrode in order to realize an antiparallel magnetization alignment.
特許請求の範囲(英語) [claim1]
1. A tunnel barrier layer disposed between a first ferromagnetic material layer and a second ferromagnetic material layer that are disposed over a substrate, wherein the tunnel barrier layer comprises a poly-crystalline magnesium oxide layer in which a (001) crystal plane is preferentially oriented,
wherein the first ferromagnetic material layer is composed of an Fe -- Co alloy of BCC which alloy comprises Fe, Co, and B,
wherein the first ferromagnetic material layer is located between the tunnel barrier layer and the substrate.
[claim2]
2. The tunnel barrier layer according to claim 1, wherein a barrier height of the tunnel barrier layer is in a range of 0.2 to 0.5 eV.
[claim3]
3. The tunnel barrier layer according to claim 2, wherein the barrier height p of the tunnel barrier layer is obtained by fitting J-V characteristics of a tunnel barrier junction structure to an equation (1):
J=[(2mphi )1/2/DELTA s](e/h)2 * exp[-(4pi DELTA s/h) * (2m#)1/2] * V (1)
where J is a tunnel current density flowing through the tunnel barrier layer, V is an applied bias voltage that is 100 mV or smaller, m is the free electron mass, e is the elementary electric charge, h is the Planck's constant, DELTA s is an effective thickness of the tunnel barrier layer that is approximately equivalent to (tMgO-0.5 nm), and tMgO is an actual thickness of the tunnel barrier layer determined using a cross-sectional transmission electron microscope image.
[claim4]
4. The tunnel barrier layer according to claim 1, wherein the second ferromagnetic material layer is composed of an alloy comprising Fe and Co, and wherein the second ferromagnetic material layer is located above the tunnel barrier layer.
[claim5]
5. The tunnel barrier layer according to claim 1, wherein the second ferromagnetic material layer is composed of an alloy comprising Fe, Co, and B, and wherein the second ferromagnetic material layer is located above the tunnel barrier layer.
[claim6]
6. The tunnel barrier layer according to claim 1, wherein the tunnel barrier layer is disposed on the first ferromagnetic material layer.
  • 発明者/出願人(英語)
  • YUASA SHINJI
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
  • NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY
国際特許分類(IPC)
参考情報 (研究プロジェクト等) PRESTO Nanostructure and Material Property AREA
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