Tunnel Magnetoresistance with Top Layer Plasma Oxidation Time in Doubly Oxidized Barrier Process
Tunnel Magnetoresistance with Top Layer Plasma Oxidation Time in Doubly Oxidized Barrier Process
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双氧化势垒工艺中具有顶层等离子体氧化时间的隧道磁阻
DOI：
10.4283/jkms.2002.12.3.099
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
O. Song
中科院分区：
文献类型：
--
作者：
Kiyung Lee;O. Song
采用等离子体氧化法制备双氧化隧道势垒的TMR器件，形成均匀氧化的AlO隧道势垒。我们溅射10 -底部Al层，氧化时间为10秒，随后溅射13 -Al层，氧化时间分别为50、80和120秒。随着氧化时间的增加，电阻从500 Ω变化到2000 Ω，而磁流变率变化不大，为27 ~ 31%，比普通单通道势垒的TMR装置大。我们通过测量I-V曲线计算了有效势垒高度和宽度，发现势垒高度为1.3 ~ 1.8 eV足以形成隧道势垒，势垒宽度（）小于物理厚度。我们的结果可能是由于Al前驱体未充分氧化成a10引起的。双氧化隧道势垒在均匀性和密度上均优于传统的单氧化隧道势垒。结果表明，采用双氧化隧道势垒工艺可以提高磁流变比和调节电阻。
We fabricated TMR devices which have doubly oxidized tunnel barrier using plasma oxidation method to form homogeneously oxidized AlO tunnel barrier. We sputtered 10 -bottom Al layer and oxidized it with oxidation time of 10 sec. Subsequent sputtering of 13 -Al was performed and the metallic layer was oxidized for 50, 80, and 120 sec., respectively. The electrical resistance changed from 500 Ω to 2000 Ω with increase of oxidation time, while variation of MR ratio was little spreading 27∼31 % which is larger than that of TMR device of ordinary single tunnel barrier. We calculated effective barrier height and width by measuring I-V curves, from which we found the barrier height was 1.3∼1.8 eV sufficient for tunnel barrier, and the barrier width () was smaller than physical thickness. Our results may be caused by insufficient oxidation of Al precursor into A1O. However, doubly oxidized tunnel barriers were superior to conventional single tunnel barrier in uniformity and density. Our results imply that we were able to improve MR ratio and tune resistance by employing doubly oxidized tunnel barrier process.