Dependence of tunnel magnetoresistance in MgO based magnetic tunnel junctions on Ar pressure during MgO sputtering
Dependence of tunnel magnetoresistance in MgO based magnetic tunnel junctions on Ar pressure during MgO sputtering
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DOI：
10.1143/jjap.44.l1442
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发表时间：
2005-01-01
期刊：
影响因子：
--
通讯作者：
Ohno, H
中科院分区：
文献类型：
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作者：
Ikeda, S;Hayakawa, J;Ohno, H
研究了在MgO阻挡层溅射过程中，Ar气压对CoFeB/MgO/CoFeB磁性隧道结中隧道磁电阻效应的影响。在10 mTorr的高Ar压力下溅射沉积MgO阻挡层导致光滑的表面和高度（001）取向的MgO。使用该MgO作为隧道势垒，在325 ℃或更高温度下退火后，实现了室温下高达355%（5 K下为578%）的隧道磁阻（TMR）比，这似乎与由光滑且高度取向的MgO促进的高度（001）取向的CoFeB织构有关。具有低电阻率Au底层和高压沉积MgO的电子束光刻限定的深亚微米MTJ在低于10 Ω μ m（2）的低电阻率-面积积（RA）下显示出高TMR比，在RA = 0.8 Ω μ m（2）时为27%，在RA = 1.1 Ω μ m（2）时为77%，在RA = 1.7 Ω μ m（2）时为130%，在RA = 2.9 Ω μ m（2）时为165%。
We investigated dependence of tunnel magnetoresistance effect in CoFeB/MgO/CoFeB magnetic tunnel junctions on Ar pressure during MgO-barrier sputtering. Sputter deposition of MgO-barrier at high Ar pressure of 10 mTorr resulted in smooth surface and highly (001) oriented MgO. Using this MgO as a tunnel barrier, tunnel magnetoresistance (TMR) ratio as high as 355% at room temperature (578% at 5 K) was realized after annealing at 325 degrees C or higher, which appears to be related to a highly (001) oriented CoFeB texture promoted by the smooth and highly oriented MgO. Electron-beam lithography defined deep-submicron MTJs having a low-resistivity Au underlayer with the high-pressure deposited MgO showed high TMR ratio at low resistance-area product (RA) below 10 Omega mu m(2) as 27% at RA = 0.8 Omega mu m(2), 77% at RA = 1.1 Omega mu m(2), 130% at RA = 1.7 Omega mu m(2), and 165% at RA = 2.9 Omega mu m(2).