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Development of spin funneling magnetic field sensor devices for high sensitive and high space-resolution magnetic imaging plates

高灵敏度、高空间分辨率磁成像板自旋漏斗磁场传感器器件的研制

基本信息

批准号：
14205060
负责人：
TAKAHASHI Migaku
金额：
$ 33.53万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

In order to realize a high sensitive and high space-resolution magnetic imaging plate, we investigated fabrication processes of spin tunneling magnetic field sensor devices. With the microwave excited plasma oxidizatioin or nitridation method using radial line slot antenna (RLSA) irradiator, ferromagnetic tunnel junctions (MTJs) in stack of bottom-electrode/Mn-Ir/Co-Fe/barrier/Co-Fe/Ni-Fe/upper-electrode were fabricated on a thermally oxidized Si wafer. The barrier was formed by the plasma oxidization or nitridation process with X+O_2 or X+N_2 (X=He,Ar,Kr) mixed gases, immediately after the deposition of 0.8-1.5 nm-thick metal Al films. In the case of MTJs with Al-O barrier oxidized from 1.5-nm-thick Al film, the maximum TMR ratio was achieved to 58.8%, which was the world record at the time. In the case of MTJs with Al-N barrier nitrided from 1.0-nm-thick Al film, the maximum TMR ratio overcame the conventional record of 33% and reached 49%. It was also found that plasma nitridation of metal Al films progresses more mildly than the plasma oxidization of them. This means that the plasma nitridation is suitable for the formation process of ultra-thin barrier layers. High concentration ozone oxidization process of ultra-thin metal films and magnetotransport properties of MTJs fabricated with this process were also investigated. As results followings were found. The oxidization process of metal films are different between the ozone exposure method and the plasma exposure method. The oxidizing rate (parabolic rate constant, k_p), dominated by the diffusion velocity of oxidizing species in the oxide layer, is smaller by two-orders in magnitude for the ozone process than that for the plasma process, while the thickness of oxide layer, immediately formed on the surface at the very early stage of oxidization, is almost same. This means that the high concentration ozone oxidization method is suitable for the precise control of oxidization of ultra-thin metal films.

为了实现高灵敏度和高空间分辨率的磁成像板，我们研究了自旋隧道磁场传感器器件的制备工艺。利用径向线缝隙天线（RLSA）辐射器，采用微波激励等离子体氧化或氮化的方法，在热氧化的硅片上制备了底电极/Mn-Ir/Co-Fe/阻挡层/Co-Fe/Ni-Fe/上电极堆叠结构的铁磁隧道结（MTJ）。在沉积0.8- 1.5nm厚的金属Al膜后，立即用X+O_2或X+N_2（X=He，Ar，Kr）混合气体进行等离子体氧化或氮化处理，形成阻挡层。在具有由1.5 nm厚的Al膜氧化的Al-O阻挡层的MTJ的情况下，最大TMR比率达到58.8%，这是当时的世界纪录。在具有从1.0 nm厚的Al膜氮化的Al-N阻挡层的MTJ的情况下，最大TMR比克服了33%的常规记录，达到49%。研究还发现，等离子体氮化的金属铝膜的进展更温和的等离子体氧化。这意味着等离子体氮化适用于超薄阻挡层的形成工艺。研究了超薄金属薄膜的高浓度臭氧氧化工艺以及用该工艺制备的MTJ的磁输运特性。结果表明：臭氧暴露法和等离子体暴露法的金属膜氧化过程不同。氧化速率（抛物线速率常数k_p）由氧化物在氧化层中的扩散速度决定，臭氧氧化比等离子体氧化小两个数量级，而氧化初期在表面立即形成的氧化层厚度几乎相同。这意味着高浓度臭氧氧化法适用于超薄金属膜氧化的精确控制。

项目成果

期刊论文数量（24）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Correlation between Oxidation Process of Al Film for Magnetic Tunnel Junctions and Oxidizing Species in the Microwave Excited Plasma

微波激发等离子体中磁隧道结铝膜氧化过程与氧化物种的相关性

DOI：
发表时间：
2003
期刊：
Journal of Magnetic Society Japan 27
影响因子：
0
作者：
Yuichi Taguchi;Takeshi Naemura;S.Yoshimura et al.
通讯作者：
S.Yoshimura et al.

Magnetotransport properties of Co-Fe/Al-N/Co-Fe tunnel junctions with large tunnel magnetoresistance ratio

大隧道磁阻比Co-Fe/Al-N/Co-Fe隧道结的磁输运特性

DOI：
发表时间：
2004
期刊：
Applied Physics Letters 85
影响因子：
0
作者：
Tae Sick Yoon;Toshihiro Shoyama;Young Woo Lee;Masakiyo Tsunoda;Migaku Takahashi;Dong Yung Kim;Chong Oh Kim
通讯作者：
Chong Oh Kim

強磁性トンネル接合膜用バリア層材料

铁磁隧道结薄膜势垒层材料