JP2001217478A - Magnetic resistance element - Google Patents
Magnetic resistance elementInfo
- Publication number
- JP2001217478A JP2001217478A JP2000024474A JP2000024474A JP2001217478A JP 2001217478 A JP2001217478 A JP 2001217478A JP 2000024474 A JP2000024474 A JP 2000024474A JP 2000024474 A JP2000024474 A JP 2000024474A JP 2001217478 A JP2001217478 A JP 2001217478A
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- Prior art keywords
- ferromagnetic film
- film
- magnetoresistive element
- magnetization
- ferromagnetic
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、外部磁界の変化に
応じて抵抗を変化させる磁気抵抗素子に係り、特に回転
している外部磁界の方向、時間経過にしたがって変化す
る外部磁界の方向などの外部磁界の方向を検出するのに
適した磁気抵抗素子に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive element which changes its resistance in response to a change in an external magnetic field, and more particularly, to the direction of a rotating external magnetic field, the direction of an external magnetic field which changes with time, and the like. The present invention relates to a magnetoresistive element suitable for detecting a direction of an external magnetic field.
【０００２】[0002]
【従来の技術】従来から、ＮｉＦｅ等の異方性磁気抵抗
効果を利用した磁気抵抗素子、電子のスピンの向きに依
存した散乱を利用して巨大磁気抵抗効果（ＧＭＲ効果）
を得る磁気抵抗素子などがよく知られているとともに、
これらの磁気抵抗素子を用いて外部磁界の方向を検出す
ることも試みられている。この種の磁気抵抗素子の特性
を評価する性質の１つに磁気抵抗変化率があり、この磁
気抵抗変化率は前者では約３％の値を示し、後者では約
１０％の値を示す。2. Description of the Related Art Conventionally, a magnetoresistive element utilizing the anisotropic magnetoresistive effect of NiFe or the like, and a giant magnetoresistive effect (GMR effect) utilizing scattering depending on the spin direction of electrons.
Are well known,
Attempts have been made to detect the direction of an external magnetic field using these magnetoresistive elements. One of the properties for evaluating the characteristics of this type of magnetoresistive element is a magnetoresistance change rate. The magnetoresistance change rate is about 3% in the former and about 10% in the latter.
【０００３】一方、これらの磁気抵抗素子に対し、近
年、磁気抵抗変化率が２０〜３０％という大きな値を示
す磁気トンネル効果を利用した磁気抵抗素子が出現して
きている。この磁気抵抗素子は、例えば特開平１０−４
２２７号公報に示されているように、強磁性膜及び反強
磁性膜からなって磁化の向きを固定した固定磁化層と、
強磁性膜からなって磁化の向きを外部磁界によって自由
に変化させるようにした自由磁化層との間に絶縁層を挟
んだ磁気トンネル接合構造を有するように構成されてい
る。On the other hand, in recent years, magnetoresistive elements utilizing the magnetic tunnel effect exhibiting a large magnetoresistance change ratio of 20 to 30% have emerged. This magnetoresistive element is disclosed in, for example,
No. 227, a fixed magnetic layer comprising a ferromagnetic film and an antiferromagnetic film and having a fixed magnetization direction,
It is configured to have a magnetic tunnel junction structure in which an insulating layer is sandwiched between a ferromagnetic film and a free magnetic layer in which the direction of magnetization is freely changed by an external magnetic field.
【０００４】[0004]
【発明が解決しようとする課題】本発明者等は、この磁
気トンネル接合を有する磁気抵抗素子を用いて、回転し
ている外部磁界の方向、時間経過にしたがって変化する
外部磁界の方向などの外部磁界の方向を検出するための
高感度の磁気抵抗素子を製作することを試みた。この場
合、外部磁界の回転方向を反転すると、図１２に示すよ
うに、磁気ヒステリシスのために、外部磁界の方向が磁
気抵抗素子の固定磁化の方向と直交する角度（１８０
度）付近で、同一の抵抗値（電圧値）を示す角度に正方
向回転時と逆方向回転時とで角度差Δθが生じる。この
角度差Δθは、外部磁界の検出方向の精度を悪化させる
ものであるとともに、同角度差Δθの生じる部分は外部
磁界の変化に対して抵抗値の最も大きく変化する部分で
あって、所定範囲内の外部磁界の方向を検出するために
重要な部分である。したがって、本発明はこの角度差Δ
θを小さくすることを課題とする。The present inventors use the magnetoresistive element having the magnetic tunnel junction to apply an external magnetic field such as the direction of a rotating external magnetic field and the direction of an external magnetic field that changes with time. An attempt was made to produce a highly sensitive magnetoresistive element for detecting the direction of a magnetic field. In this case, when the rotation direction of the external magnetic field is reversed, as shown in FIG. 12, due to magnetic hysteresis, the direction of the external magnetic field becomes an angle (180) orthogonal to the direction of the fixed magnetization of the magnetoresistive element.
(Degree), an angle difference Δθ is generated between an angle indicating the same resistance value (voltage value) between the forward rotation and the reverse rotation. The angle difference Δθ deteriorates the accuracy of the detection direction of the external magnetic field, and a portion where the angle difference Δθ occurs is a portion where the resistance value changes most in response to a change in the external magnetic field, and is within a predetermined range. This is an important part for detecting the direction of the external magnetic field inside. Therefore, the present invention provides this angular difference Δ
It is an object to reduce θ.
【０００５】[0005]
【発明の概略】本発明は、上記課題に対処するためにな
されたものであり、その目的は、外部磁界の方向を精度
よく検出可能な磁気抵抗素子（磁気センサ）を提供しよ
うとするものである。SUMMARY OF THE INVENTION The present invention has been made to address the above-mentioned problems, and an object of the present invention is to provide a magnetoresistive element (magnetic sensor) capable of accurately detecting the direction of an external magnetic field. is there.
【０００６】上記目的を達成するために、本発明の構成
上の特徴は、磁化の向きを固定した固定磁化層と、磁化
の向きを自由に変化させるようにした自由磁化層との間
に絶縁層を挟んで構成した磁気トンネル接合構造を有
し、前記自由磁化層を長方形状に形成するとともに、前
記固定磁化層の磁化の向きを前記自由磁化層の短辺方向
と一致させたことにある。この場合、前記自由磁化層の
短辺の長さに対する長辺の長さの比を４以上に設定する
とよい。In order to achieve the above object, a structural feature of the present invention is that an insulating layer is provided between a fixed magnetization layer having a fixed magnetization direction and a free magnetization layer having a magnetization direction freely changed. A free magnetic layer having a rectangular shape, and a direction of magnetization of the fixed magnetic layer coinciding with a short side direction of the free magnetic layer. . In this case, the ratio of the length of the long side to the length of the short side of the free magnetic layer is preferably set to 4 or more.
【０００７】また、前記固定磁化層を、前記絶縁層に接
する第１強磁性膜と、前記第１強磁性膜の前記絶縁層と
反対側の面に接して前記第１強磁性膜の磁化の方向を固
定するための第２強磁性膜とで構成できる。また、前記
固定磁化層を、前記絶縁層に接する強磁性膜と、前記強
磁性膜の前記絶縁層と反対側の面に接して前記強磁性膜
の磁化の方向を固定するための反強磁性膜とで構成する
こともできる。[0007] The fixed magnetic layer may include a first ferromagnetic film in contact with the insulating layer and a first ferromagnetic film in contact with a surface of the first ferromagnetic film opposite to the insulating layer, the magnetization of the first ferromagnetic film. And a second ferromagnetic film for fixing the direction. Further, the pinned magnetic layer is made of a ferromagnetic film in contact with the insulating layer, and an antiferromagnetic film for fixing the direction of magnetization of the ferromagnetic film in contact with a surface of the ferromagnetic film opposite to the insulating layer. It can also be composed of a film.
【０００８】さらに、本発明の特徴は、上記のような磁
気抵抗素子を、前記固定磁化層、絶縁層及び自由磁化層
の積層方向と直交する面内を通過する外部磁界の方向を
検出することに用いるようにしたことにもある。Further, a feature of the present invention is to detect the direction of an external magnetic field passing through the above-described magnetoresistive element in a plane orthogonal to the lamination direction of the fixed magnetic layer, the insulating layer and the free magnetic layer. It has been used for.
【０００９】このように構成した本発明によれば、外部
磁界の回転方向が反転しても、磁界の正方向回転時と逆
方向回転時との上記角度差Δθを小さくすることがで
き、外部磁界の方向を精度よく検出することができるよ
うになる。According to the present invention configured as described above, even when the rotation direction of the external magnetic field is reversed, the angle difference Δθ between when the magnetic field rotates in the forward direction and when the magnetic field rotates in the reverse direction can be reduced. The direction of the magnetic field can be accurately detected.
【００１０】また、前記構成の磁気抵抗素子において
は、測定する外部磁界の強さが自由磁化層の保磁力と固
定磁化層の保磁力との間の値になるように設定する必要
があり、自由磁化層の保磁力は外部磁界の強さよりも小
さくするほど好ましく、固定磁化層の保磁力は外部磁界
の強さよりも大きくするほど好ましい。また、自由磁化
層の短辺の幅は３μｍ以上であることが好ましい。In the magnetoresistive element having the above-described structure, it is necessary to set the strength of the external magnetic field to be measured to be a value between the coercive force of the free magnetic layer and the coercive force of the fixed magnetic layer. The coercive force of the free magnetic layer is preferably smaller than the strength of the external magnetic field, and the coercive force of the fixed magnetic layer is more preferable to be larger than the strength of the external magnetic field. The width of the short side of the free magnetic layer is preferably 3 μm or more.
【００１１】また、固定磁化層を第１及び第２強磁性膜
で構成する場合、第１強磁性膜としては、磁気抵抗素子
の抵抗変化率を大きくするために分極率の大きな膜材料
（例えば、ＮｉＦｅ）を用いるとともに、固定磁化層の
保磁力の低下を回避するために第１強磁性膜の膜厚をな
るべく薄く、例えば５〜２０ｎｍ程度に設定するとよ
い。また、第２強磁性膜は、第１強磁性膜の磁化の方向
を固定するためのものであるから、保磁力をなるべく大
きくし、第１及び第２強磁性膜からなる固定磁化層の合
計保磁力を例えば５００エルステッド以上に設定するこ
とが好ましい。これは、固定磁化層の保磁力より強い外
部磁界が付与された場合、第１及び第２強磁性膜の磁化
の向きが外部磁界の方向と同じ向きになってしまい、外
部磁界を取り除いても磁化は前記外部磁界と同じ向きに
保たれるので、センサとして使用するのに適さないため
である。In the case where the fixed magnetic layer is composed of the first and second ferromagnetic films, the first ferromagnetic film is made of a film material having a large polarizability (for example, a film material for increasing the rate of change in resistance of the magnetoresistive element). , NiFe), and the thickness of the first ferromagnetic film is preferably set to be as small as possible, for example, about 5 to 20 nm in order to avoid a decrease in the coercive force of the fixed magnetic layer. Since the second ferromagnetic film is for fixing the direction of magnetization of the first ferromagnetic film, the coercive force is increased as much as possible, and the total of the fixed magnetic layer composed of the first and second ferromagnetic films is increased. It is preferable to set the coercive force to, for example, 500 Oe or more. This is because, when an external magnetic field stronger than the coercive force of the fixed magnetic layer is applied, the directions of magnetization of the first and second ferromagnetic films become the same as the direction of the external magnetic field. This is because the magnetization is kept in the same direction as the external magnetic field and is not suitable for use as a sensor.
【００１２】固定磁化層を強磁性膜と反強磁性膜とで構
成する場合、前記固定磁化層を第１及び第２強磁性膜で
構成する場合と異なり、固定磁化層のうち強磁性膜の保
磁力よりも強い外部磁界が付与されたときには、強磁性
膜の磁化の向きは外部磁界の方向と同じ向きになるが、
反強磁性膜の磁化の向きは元の向きに保たれる。充分に
大きな外部磁界を付与した場合には、反強磁性膜の磁化
の向きも外部磁界と同じ方向になり、このときの外部磁
界の強さを交換結合磁界といい、この交換結合磁界より
強い外部磁界が付与されると、センサとして使用するの
に適さない。したがって、反強磁性膜として交換結合磁
界の大きな膜材料を用いるとともに、前記固定磁化層を
第１及び第２強磁性膜で構成する場合と同様に、強磁性
膜としては分極率の高い膜材料（例えば、ＮｉＦｅ）を
用い、強磁性膜の膜厚を薄く、例えば５〜１０ｎｍ程度
に設定するとよい。When the fixed magnetic layer is composed of a ferromagnetic film and an antiferromagnetic film, unlike the case where the fixed magnetic layer is composed of the first and second ferromagnetic films, the fixed magnetic layer is formed of the ferromagnetic film. When an external magnetic field stronger than the coercive force is applied, the direction of magnetization of the ferromagnetic film becomes the same as the direction of the external magnetic field,
The direction of the magnetization of the antiferromagnetic film is kept in the original direction. When a sufficiently large external magnetic field is applied, the direction of magnetization of the antiferromagnetic film also becomes the same direction as the external magnetic field, and the strength of the external magnetic field at this time is called an exchange coupling magnetic field, which is stronger than the exchange coupling magnetic field. If an external magnetic field is applied, it is not suitable for use as a sensor. Therefore, a film material having a large exchange coupling magnetic field is used as the antiferromagnetic film, and a film material having a high polarizability is used as the ferromagnetic film, as in the case where the fixed magnetic layer is formed of the first and second ferromagnetic films. (For example, NiFe), the thickness of the ferromagnetic film may be set to be thin, for example, about 5 to 10 nm.
【００１３】また、前記固定磁化層を第１及び第２強磁
性膜で構成する場合、第２強磁性膜をＣｏＰｔＣｒ，Ｃ
ｏＴａＣｒ，ＣｏＣｒなどのＣｏを含む合金で構成する
とよい。これによれば、高温時にも良好な特性を得るこ
とができる。When the fixed magnetic layer is composed of first and second ferromagnetic films, the second ferromagnetic film is made of CoPtCr, C
It is preferable to use an alloy containing Co such as oTaCr and CoCr. According to this, good characteristics can be obtained even at a high temperature.
【００１４】さらに、前記のように構成した磁気トンネ
ル接合構造を複数直列に接続して用いるとよい。これに
よれば、磁気抵抗素子の全体の抵抗を大きくすることが
でき、同素子にある程度大きな電圧を付与することがで
きるようになるとともに、大きな抵抗値（電圧値）の変
化を取出すことができるようになる。Further, a plurality of magnetic tunnel junction structures configured as described above may be connected in series and used. According to this, the overall resistance of the magnetoresistive element can be increased, a large voltage can be applied to the element, and a large change in the resistance value (voltage value) can be obtained. Become like
【００１５】[0015]
【発明の実施の形態】以下、本発明の一実施形態に係る
磁気抵抗素子（磁気センサ）について、図面を用いて説
明する。図１は同実施形態に係る磁気抵抗素子の一部を
示す概略断面図であり、図２，３は、図１に対応した磁
気抵抗素子の概略平面図である。なお、図２，３におい
ては、各層の接続状態を理解し易くするために、各層の
寸法を異ならせて示している。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetoresistive element (magnetic sensor) according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view showing a part of the magnetoresistive element according to the embodiment, and FIGS. 2 and 3 are schematic plan views of the magnetoresistive element corresponding to FIG. In FIGS. 2 and 3, the dimensions of each layer are shown differently so that the connection state of each layer can be easily understood.
【００１６】この磁気抵抗素子は、例えばＳｉＯ２／Ｓ
ｉ、ガラス又は石英からなる基板１０を備えている。基
板１０上には、平面形状を長方形状に形成した複数の下
部電極１１が横方向に所定の間隔を隔てて一列に配置さ
れており、同下部電極１１は、導電性非磁性金属材料で
あるＣｒ（又はＴｉ）により膜厚１０ｎｍ程度に形成さ
れている。各下部電極１１上には、下部電極１１と同一
平面形状に形成され、ＣｏＰｔＣｒからなり膜厚３０ｎ
ｍ程度の強磁性膜１２がそれぞれ積層されている。この
強磁性膜１２においては、その保磁力を、後述する外部
磁界の強さよりも必ず大きくする必要があり、同外部磁
界の強さよりも大きくするほど好ましい。そして、後述
する強磁性膜１３とにより構成される固定磁化層との合
計の保磁力は、例えば５００エルステッド以上に設定さ
れている。この場合、強磁性膜１２の磁化は、磁気抵抗
素子の製造工程中に又は完成後に行われるもので、少な
くとも同磁気抵抗素子の使用時には、この強磁性膜１２
は図３の矢印方向に既に磁化されている。This magnetoresistive element is, for example, SiO 2 / S
i, a substrate 10 made of glass or quartz. On the substrate 10, a plurality of lower electrodes 11 having a rectangular planar shape are arranged in a row at predetermined intervals in the horizontal direction, and the lower electrodes 11 are made of a conductive non-magnetic metal material. It is formed to a film thickness of about 10 nm by Cr (or Ti). On each lower electrode 11, it is formed in the same plane shape as the lower electrode 11, is made of CoPtCr, and has a thickness of 30n.
About m ferromagnetic films 12 are respectively stacked. In the ferromagnetic film 12, the coercive force must be always larger than the strength of an external magnetic field described later, and it is more preferable that the coercive force be larger than the strength of the external magnetic field. The total coercive force with the fixed magnetic layer constituted by the ferromagnetic film 13 described later is set to, for example, 500 Oe or more. In this case, the magnetization of the ferromagnetic film 12 is performed during the manufacturing process of the magnetoresistive element or after completion thereof.
Are already magnetized in the direction of the arrow in FIG.
【００１７】各強磁性膜１２上には、膜厚５ｎｍ程度の
ＮｉＦｅからなる一対の強磁性膜１３，１３が間隔を隔
てて積層されている。この強磁性膜１３，１３の平面形
状は長方形状（例えば、２０×１２０μｍ）に形成さ
れ、各長辺を平行に対向させて配置されるとともに、そ
の短辺方向を前記強磁性膜１２の磁化方向と同一にして
いる。また、この強磁性膜１３は強磁性膜１２と共に磁
化の向きを固定した固定磁化層を構成するものであり、
前記強磁性膜１２の磁化により、図３に示すように短辺
方向に磁化される。なお、この強磁性膜１３としては、
磁気抵抗素子の抵抗変化率を大きくするために、分極率
の大きな材料が用いられるとともに、前記固定磁化層全
体の保磁力の低下を回避するために膜厚をなるべく薄
く、例えば５〜２０ｎｍ程度に設定することが好まし
い。On each ferromagnetic film 12, a pair of ferromagnetic films 13 made of NiFe having a film thickness of about 5 nm are laminated at intervals. The planar shape of the ferromagnetic films 13 and 13 is formed in a rectangular shape (for example, 20 × 120 μm), the long sides are arranged in parallel with each other, and the short side direction is the magnetization of the ferromagnetic film 12. It is the same as the direction. The ferromagnetic film 13 and the ferromagnetic film 12 constitute a fixed magnetization layer having a fixed magnetization direction.
Due to the magnetization of the ferromagnetic film 12, it is magnetized in the short side direction as shown in FIG. In addition, as this ferromagnetic film 13,
In order to increase the rate of change in resistance of the magnetoresistive element, a material having a large polarizability is used, and the film thickness is set to be as small as possible, for example, about 5 to 20 nm in order to avoid a decrease in the coercive force of the entire fixed magnetic layer. It is preferable to set.
【００１８】各強磁性膜１３上には、同強磁性膜１３と
同一平面形状を有する絶縁層１４及び強磁性膜１５がそ
れぞれこの順に積層されている。絶縁層１４は、膜厚３
〜４ｎｍ程度のＡｌ２Ｏ３の絶縁材料により構成されて
いる。強磁性膜１５は、絶縁層１４に接する膜厚２ｎｍ
程度のＣｏ膜を下層とし、同Ｃｏ膜に接する膜厚６０ｎ
ｍ程度のＮｉＦｅ膜を上層とする２層構造に構成されて
いて、絶縁層１４と強磁性膜１２，１３（固定磁化層）
と共に磁気トンネル接合構造を形成するものである。こ
の強磁性膜１５は、その磁化の向きを外部磁界の向きに
自由（フリー）に変える自由磁化層（フリー層）を構成
するものであるため、その保磁力を後述する外部磁界の
強さよりも必ず小さくする必要があり、同外部磁界の強
さよりも小さくするほど好ましい。本実施例の構成で
は、この値は、例えば１５〜４０エルステッド程度に設
定されている。On each ferromagnetic film 13, an insulating layer 14 and a ferromagnetic film 15 having the same planar shape as the ferromagnetic film 13 are respectively laminated in this order. The insulating layer 14 has a thickness of 3
It is made of an insulating material of Al 2 O 3 of about 4 nm. The ferromagnetic film 15 has a thickness of 2 nm in contact with the insulating layer 14.
About 60 n in thickness in contact with the Co film.
It has a two-layer structure in which a NiFe film of about m is formed as an upper layer, and has an insulating layer 14 and ferromagnetic films 12 and 13 (fixed magnetic layer).
Together with the magnetic tunnel junction structure. Since the ferromagnetic film 15 constitutes a free magnetic layer (free layer) that changes the direction of its magnetization to the direction of an external magnetic field (free), its coercive force is higher than that of an external magnetic field described later. It is necessary to make it smaller, and it is more preferable to make it smaller than the strength of the external magnetic field. In the configuration of the present embodiment, this value is set to, for example, about 15 to 40 Oe.
【００１９】各強磁性膜１５上には、同各強磁性膜１５
と同一平面形状のダミー膜１６がそれぞれ形成されてい
る。これは、後述するコンタクトホール１７ａを形成す
る際、強磁性膜１５及び絶縁層１４にまでエッチングが
及ばないようにするためである。このダミー膜１６は、
膜厚３０ｎｍ程度のＭｏ膜からなる導電性非磁性金属材
料によって構成されている。On each ferromagnetic film 15, the same ferromagnetic film 15
And dummy films 16 having the same planar shape are formed. This is to prevent the etching from reaching the ferromagnetic film 15 and the insulating layer 14 when forming a contact hole 17a described later. This dummy film 16
It is made of a conductive non-magnetic metal material made of a Mo film having a thickness of about 30 nm.
【００２０】基板１０、下部電極１１、強磁性膜１２，
１３、絶縁層１４、強磁性膜１５及びダミー膜１６を覆
う領域には、複数の下部電極１１及び強磁性膜１２をそ
れぞれ絶縁分離するとともに、各強磁性膜１２上に設け
た一対の強磁性膜１３、絶縁層１４、強磁性膜１５及び
ダミー膜１６をそれぞれ絶縁分離するための層間絶縁膜
１７が設けられている。この層間絶縁膜１７は、例えば
ＳｉＯ２からなって膜厚２５０ｎｍ程度に形成されてい
る。The substrate 10, the lower electrode 11, the ferromagnetic film 12,
13, a plurality of lower electrodes 11 and a plurality of ferromagnetic films 12 are insulated and separated from each other in a region covering the insulating layer 14, the ferromagnetic film 15 and the dummy film 16, and a pair of ferromagnetic films provided on each of the ferromagnetic films 12 is provided. An interlayer insulating film 17 for insulating the film 13, the insulating layer 14, the ferromagnetic film 15, and the dummy film 16 from each other is provided. The interlayer insulating film 17 is made of, for example, SiO 2 and has a thickness of about 250 nm.
【００２１】この層間絶縁膜１７には、各ダミー膜１６
上にてコンタクトホール１７ａがそれぞれ形成されてい
る。このコンタクトホール１７ａを埋設するとともに、
異なる下部電極１１及び強磁性膜１２上に設けた一対の
ダミー膜１６，１６の各一方間を互いに電気的に接続す
るように、例えば膜厚３００ｎｍのＡｌからなる上部電
極１８，１８がそれぞれ形成されている。このようにし
て、図２に示すように、下部電極１１及び強磁性膜１２
と、上部電極１８とにより、隣り合う一対の磁気トンネ
ル接合構造の各強磁性膜１５，１５（各ダミー膜１６，
１６）と各強磁性膜１２，１２とをそれぞれ交互に順次
電気的に接続して、複数の磁気トンネル接合構造を直列
に接続した磁気抵抗素子が形成されている。Each interlayer insulating film 17 has a dummy film 16
Above, contact holes 17a are respectively formed. While burying this contact hole 17a,
Upper electrodes 18 made of, for example, 300 nm thick Al are formed so as to electrically connect one of the pair of dummy films 16 provided on the different lower electrode 11 and the ferromagnetic film 12 to each other. Have been. In this manner, as shown in FIG.
And the upper electrode 18, the ferromagnetic films 15, 15 (each of the dummy films 16, 15) having a pair of adjacent magnetic tunnel junction structures
16) and the ferromagnetic films 12 and 12 are electrically connected alternately and sequentially to form a magnetoresistive element in which a plurality of magnetic tunnel junction structures are connected in series.
【００２２】次に、前述のような磁気トンネル接合構造
を、マトリクス（ミランダ）構造を用いて多数直列に接
続した磁気抵抗素子（磁気センサ）について説明してお
く。図４は、このマトリクス構造に係る磁気抵抗素子を
平面図により示しており、方形状の基板１０（図示省
略）上に、磁気トンネル接合構造をマトリクス上に配置
している。Next, a description will be given of a magnetoresistive element (magnetic sensor) in which a number of the above magnetic tunnel junction structures are connected in series using a matrix (Miranda) structure. FIG. 4 is a plan view showing a magnetoresistive element according to this matrix structure, in which a magnetic tunnel junction structure is arranged on a matrix on a square substrate 10 (not shown).
【００２３】前記のように、共通の下部電極１１及び強
磁性膜１２（図示省略）上に、平面形状を長方形に形成
して強磁性膜１３、絶縁層１４、強磁性膜１５及びダミ
ー膜１６を積層した一対の磁気トンネル接合構造が長辺
を縦方向にして平行かつ対向してマトリクス状に配置さ
れ、前記一対の磁気トンネル接合構造をそれぞれ配置さ
せてなる複数の共通の下部電極１１及び強磁性膜１２が
基板１０上にて横方向に直線的に配置されるとともに縦
方向に複数列にわたって配置されている。そして、左右
両端の磁気トンネル接合構造（Ｘで示す）以外の磁気ト
ンネル接合構造に関しては、横方向に隣り合う一対の磁
気トンネル接合構造の各ダミー膜１６，１６（強磁性膜
１５，１５）が上部電極１８によって横方向に直線的に
直列接続されている。左右両端の磁気トンネル接合構造
（Ｘで示す）に関しては、図示上下一対の磁気トンネル
接合構造の各ダミー膜１６，１６（各強磁性膜１５，１
５）が縦長の上部電極１８によりそれぞれ接続されてい
る。As described above, the rectangular shape is formed on the common lower electrode 11 and the ferromagnetic film 12 (not shown) so that the ferromagnetic film 13, the insulating layer 14, the ferromagnetic film 15, and the dummy film 16 are formed. Are arranged in a matrix in parallel with each other with the long sides in the longitudinal direction and opposed to each other, and a plurality of common lower electrodes 11 and a plurality of common lower electrodes 11 each having the pair of magnetic tunnel junction structures are arranged. The magnetic films 12 are linearly arranged in the horizontal direction on the substrate 10 and are arranged in a plurality of columns in the vertical direction. As for the magnetic tunnel junction structures other than the magnetic tunnel junction structures at the left and right ends (indicated by X), each of the dummy films 16, 16 (ferromagnetic films 15, 15) of the pair of magnetic tunnel junction structures adjacent in the lateral direction is formed. The upper electrodes 18 are linearly connected in series in the horizontal direction. Regarding the magnetic tunnel junction structures at both left and right ends (indicated by X), each of the dummy films 16, 16 (each ferromagnetic film 15, 1) of the pair of upper and lower magnetic tunnel junctions in the figure is shown.
5) are connected by vertically elongated upper electrodes 18 respectively.
【００２４】このように磁気トンネル接合構造をマトリ
クス状に配置することにより、多数の磁気トンネル接合
構造を直列に接続することができ、磁気抵抗素子の全体
の抵抗が大きくなり、同素子にある程度大きな電圧を付
与することができるようになるとともに、大きな抵抗値
（電圧値）の変化を取出すことができるようになる。By arranging the magnetic tunnel junction structures in a matrix as described above, a large number of magnetic tunnel junction structures can be connected in series, the overall resistance of the magnetoresistive element increases, and the magnetoresistive element has a relatively large resistance. A voltage can be applied, and a large change in resistance (voltage) can be obtained.
【００２５】次に、上記のように構成した磁気抵抗素子
（磁気センサ）の特性について説明する。この場合、図
５に模式的に示すように、一定の電流を流した磁気抵抗
素子ＴＭＲをヘルムホルツコイル装置の中に入れ、外部
磁界すなわちヘルムホルツコイルＨＬを０〜３６０度ま
で一方向（実線矢印）に回転させ、その後に３６０〜０
度まで逆方向（点線矢印）に回転させて磁気抵抗素子Ｔ
ＭＲの両端の電圧値（抵抗値）の変化を測定した。試料
としては５００個の磁気トンネル接合構造をマトリクス
状に配置するとともに直列接続した磁気抵抗素子ＴＭＲ
を用い、同資料に０．０６ｍＡの電流を流してその両端
の電圧を測定した。なお、図中の磁気抵抗素子ＴＭＲ内
の矢印は固定磁化の方向を示し、磁気抵抗素子ＴＭＲと
ヘルムホルツコイルＨＬとの間の矢印は外部磁界の方向
を示す。Next, the characteristics of the magnetoresistive element (magnetic sensor) configured as described above will be described. In this case, as schematically shown in FIG. 5, the magnetoresistive element TMR to which a constant current has flowed is put into a Helmholtz coil device, and an external magnetic field, that is, a Helmholtz coil HL is moved in one direction from 0 to 360 degrees (solid arrow) And then 360 to 0
Degree in the opposite direction (dotted arrow) to rotate the magnetoresistive element T
The change in the voltage value (resistance value) at both ends of the MR was measured. As a sample, a magnetic resistance element TMR in which 500 magnetic tunnel junction structures are arranged in a matrix and connected in series
, A current of 0.06 mA was passed through the same material, and the voltage at both ends was measured. Note that arrows in the magnetoresistive element TMR in the figure indicate the direction of fixed magnetization, and arrows between the magnetoresistive element TMR and the Helmholtz coil HL indicate directions of an external magnetic field.
【００２６】図６(Ａ)(Ｂ)は、前記測定による電圧値
（抵抗値）の変化を示している。これによれば、１８０
度（固定磁化層の磁化の向きと外部磁界が直交する角
度）近辺で、同一の電圧値(抵抗値）を示す角度に正方
向回転時と逆方向回転時とで角度差Δθが生じた。ただ
し、図６(Ａ)(Ｂ)のグラフは、固定磁化層の磁化の向き
による影響が顕著に現れることを説明するために、各磁
気トンネル接合構造の強磁性膜１５(自由磁化層)の長辺
と短辺の長さの比が６対１（アスペクト比６）であり、
かつ固定磁化層としての強磁性膜１２，１３の磁化の向
きを強磁性膜１５(自由磁化層)の長辺方向とする磁気抵
抗素子の測定結果である。FIGS. 6A and 6B show changes in the voltage value (resistance value) based on the above measurement. According to this, 180
In the vicinity of the degree (the angle at which the direction of magnetization of the fixed magnetization layer is orthogonal to the external magnetic field), an angle difference Δθ is generated between the forward rotation and the reverse rotation at an angle showing the same voltage value (resistance value). However, the graphs of FIGS. 6A and 6B show that the influence of the magnetization direction of the fixed magnetic layer appears remarkably, so that the ferromagnetic film 15 (free magnetic layer) of each magnetic tunnel junction structure can be used. The ratio of the length of the long side to the short side is 6 to 1 (aspect ratio 6),
In addition, it is a measurement result of a magnetoresistive element in which the direction of magnetization of the ferromagnetic films 12 and 13 as fixed magnetic layers is set to the long side direction of the ferromagnetic film 15 (free magnetic layer).
【００２７】ここで、本発明者等は、各磁気トンネル接
合構造の強磁性膜１５(自由磁化層)の長辺と短辺の長さ
の比（アスペクト比）を種々に変えるとともに、強磁性
膜１２，１３（固定磁化層）の磁化の向きを強磁性膜１
５(自由磁化層)の長辺方向及び短辺方向とする種々の磁
気抵抗素子について、前記条件で最大の角度差Δθをそ
れぞれ測定した。その測定結果を図７のグラフに示す。
図7(Ａ)はヘルムホルツコイルＨＬによる外部回転磁界
の強さを２００エルステッドに設定した場合を示し、図
7(Ｂ)は同外部回転磁界の強さを１００エルステッドに
設定した場合を示している。Here, the present inventors have variously changed the ratio (aspect ratio) of the length of the long side to the short side of the ferromagnetic film 15 (free magnetic layer) of each magnetic tunnel junction structure, and The direction of magnetization of the films 12 and 13 (fixed magnetic layer) is changed to the ferromagnetic film 1.
5 (free magnetic layer) The maximum angle difference Δθ was measured for each of the various magnetoresistive elements in the long side direction and the short side direction under the above conditions. The measurement results are shown in the graph of FIG.
FIG. 7A shows a case where the strength of the external rotating magnetic field by the Helmholtz coil HL is set to 200 Oersted.
FIG. 7B shows a case where the strength of the external rotating magnetic field is set to 100 Oersted.
【００２８】外部回転磁界を２００エルステッドに設定
した場合、強磁性膜１２，１３（固定磁化層）の磁化の
向きを強磁性膜１５(自由磁化層)の長辺方向とするもの
に関しては、アスペクト比を「１」（平面形状を正方形
とするもの）、「３」、「４」、「６」と増加させるに
したがって、最大の角度差Δθは「２．８」、「４．
１」、「４．４」、「４．６」と増加した。また、強磁
性膜１２，１３（固定磁化層）の磁化の向きを強磁性膜
１５(自由磁化層)の短辺方向とするものに関しては、ア
スペクト比を「１」、「３」、「４」、「６」と増加さ
せるにしたがって、最大の角度差Δθは「２．８」、
「２．０」、「１．２８」、「０．５３」と減少した。When the external rotating magnetic field is set to 200 Oe, the direction of magnetization of the ferromagnetic films 12 and 13 (fixed magnetic layer) is set to the long side direction of the ferromagnetic film 15 (free magnetic layer). As the ratio is increased to “1” (planar shape is a square), “3”, “4”, and “6”, the maximum angle difference Δθ is “2.8”, “4.
1 "," 4.4 ", and" 4.6 ". Further, when the direction of magnetization of the ferromagnetic films 12 and 13 (fixed magnetic layer) is set to the short side direction of the ferromagnetic film 15 (free magnetic layer), the aspect ratio is set to “1”, “3”, or “4”. And “6”, the maximum angle difference Δθ is “2.8”,
"2.0", "1.28", and "0.53" decreased.
【００２９】外部回転磁界を１００エルステッドに設定
した場合、強磁性膜１２，１３（固定磁化層）の磁化の
向きを強磁性膜１５(自由磁化層)の長辺方向とするもの
に関しては、アスペクト比を「１」、「３」、「４」、
「６」と増加させるにしたがって、最大の角度差Δθは
「９．７」、「１５．２」、「１６．１」、「１７．
０」と増加した。また、強磁性膜１２，１３（固定磁化
層）の磁化の向きを強磁性膜１５(自由磁化層)の短辺方
向とするものに関しては、アスペクト比を「１」、
「３」、「４」、「６」と増加させるにしたがって、最
大の角度差Δθは「９．７」、「８．０」、「４．
７」、「２．０５」と減少した。When the external rotating magnetic field is set to 100 Oe, the direction of magnetization of the ferromagnetic films 12 and 13 (fixed magnetic layer) is set to the long side direction of the ferromagnetic film 15 (free magnetic layer). The ratios are "1", "3", "4",
As the number is increased to “6”, the maximum angle differences Δθ are “9.7”, “15.2”, “16.1”, “17.
0 ”. As for the direction of magnetization of the ferromagnetic films 12 and 13 (fixed magnetic layer) in the short side direction of the ferromagnetic film 15 (free magnetic layer), the aspect ratio is “1”,
As the number is increased to “3”, “4”, and “6”, the maximum angle differences Δθ are “9.7”, “8.0”, and “4.
7 "and" 2.05 ".
【００３０】その結果、各磁気トンネル接合構造の強磁
性膜１２，１３（固定磁化層）の磁化の向きを強磁性膜
１５(自由磁化層)の短辺方向とすると、最大の角度差θ
を小さくできることが分かった。また、磁化の向きを前
記のようにして、アスペクト比を大きくすると、最大の
角度差Δθを小さくできることも分かった。さらに、外
部磁界の強さを強磁性膜１５（自由磁化層）の保持力よ
りも大きくするほど好ましいことも分かった。ただし、
理論的にも、外部磁界の強さが強磁性膜１２，１３（固
定磁化層）の保磁力に近づくと、好ましくない。As a result, when the direction of magnetization of the ferromagnetic films 12, 13 (fixed magnetic layer) of each magnetic tunnel junction structure is set to the short side direction of the ferromagnetic film 15 (free magnetic layer), the maximum angular difference θ
Was found to be smaller. It was also found that the maximum angle difference Δθ can be reduced by increasing the aspect ratio as described above for the magnetization direction. Further, it has been found that it is preferable that the intensity of the external magnetic field be larger than the coercive force of the ferromagnetic film 15 (free magnetic layer). However,
It is theoretically undesirable that the strength of the external magnetic field approaches the coercive force of the ferromagnetic films 12 and 13 (fixed magnetic layer).
【００３１】したがって、上記例示のように、自由磁化
層である強磁性膜１５を長方形状に形成するとともに、
固定磁化層である強磁性膜１２，１３の磁化の向きを強
磁性膜１５の短辺方向と一致させれば、外部磁界の回転
方向が反転しても、同一の電圧値（抵抗値）を示す外部
磁界の正方向回転時と逆方向回転時との最大の角度差Δ
θを小さくすることができ、外部磁界の方向を精度よく
検出することができるようになる。また、アスペクト比
を大きくすればよく、同アスペクト比を４以上にすると
好ましい。Therefore, as described above, the ferromagnetic film 15, which is a free magnetic layer, is formed in a rectangular shape.
If the magnetization directions of the ferromagnetic films 12 and 13 as the fixed magnetization layers are made to coincide with the short sides of the ferromagnetic film 15, the same voltage value (resistance value) is obtained even if the rotation direction of the external magnetic field is reversed. Maximum angle difference Δ between the forward and reverse rotations of the indicated external magnetic field
θ can be reduced, and the direction of the external magnetic field can be accurately detected. Further, the aspect ratio may be increased, and the aspect ratio is preferably set to 4 or more.
【００３２】また、強磁性膜１２と外部磁界との関係に
おいては、固定磁化層の磁化の方向が外部磁界によって
変化しないようにするため、強磁性膜１２の保磁力を外
部磁界の強さよりも必ず大きく設定する必要があり、さ
らに同外部磁界の強さよりも大きくするほど好ましい。
これは、固定磁化層の保磁力より強い外部磁界が付与さ
れた場合、強磁性膜１２，１３の磁化の向きが外部磁界
の方向と同じ向きになってしまい、外部磁界を取り除い
ても磁化は前記外部磁界と同じ向きに保たれるので、セ
ンサとして使用するのに適さないためである。In the relationship between the ferromagnetic film 12 and the external magnetic field, the coercive force of the ferromagnetic film 12 is set to be smaller than the intensity of the external magnetic field in order to prevent the magnetization direction of the fixed magnetic layer from being changed by the external magnetic field. It is necessary to set it to be always large, and it is more preferable to set it to be larger than the strength of the external magnetic field.
This is because, when an external magnetic field stronger than the coercive force of the fixed magnetic layer is applied, the directions of magnetization of the ferromagnetic films 12 and 13 become the same as the direction of the external magnetic field. Because it is kept in the same direction as the external magnetic field, it is not suitable for use as a sensor.
【００３３】また、強磁性膜１５（自由磁化層）の保磁
力を外部磁界の強さよりも必ず小さく設定する必要があ
り、同外部磁界の強さよりも小さくなるほど好ましい。
さらに、強磁性膜１５の保磁力には面積依存性があり、
面積が大きいほど保磁力が小さくなる。したがって、強
磁性膜１５の短辺の長さは３μｍ以上であることが好ま
しい。強磁性膜１２の膜厚は５０ｎｍ以下であることが
好ましい。It is necessary to set the coercive force of the ferromagnetic film 15 (free magnetic layer) to be always smaller than the strength of the external magnetic field, and it is preferable that the coercive force be smaller than the strength of the external magnetic field.
Further, the coercive force of the ferromagnetic film 15 has an area dependency,
The larger the area, the smaller the coercive force. Therefore, it is preferable that the length of the short side of the ferromagnetic film 15 is 3 μm or more. The thickness of the ferromagnetic film 12 is preferably 50 nm or less.
【００３４】また、上記実施形態では、強磁性膜１２を
ＣｏＰｔＣｒを用いるようにしたが、ＣｏＣｒ、ＣｏＴ
ａＣｒなどのＣｏを含む保磁力の大きな合金で構成する
ことができる。これらの合金で強磁性膜１２を構成する
ことにより、高温時にも良好な特性を得ることができ
る。In the above embodiment, the ferromagnetic film 12 is made of CoPtCr.
It can be made of an alloy having a large coercive force including Co such as aCr. By forming the ferromagnetic film 12 with these alloys, good characteristics can be obtained even at high temperatures.
【００３５】次に、上記下部電極１１、強磁性膜１２，
１３、絶縁層１４、強磁性膜１５及びダミー膜１６から
なる積層構造の変形例について説明しておく。Next, the lower electrode 11, the ferromagnetic film 12,
A description will be given of a modified example of the laminated structure including the insulating layer 13, the insulating layer 14, the ferromagnetic film 15, and the dummy film 16.
【００３６】第１変形例は、図８に示すように、基板１
０上に複数の下部電極１１を形成するとともに、各下部
電極１１上に、同一平面形状の強磁性膜１２，１３、絶
縁層１４、強磁性膜１５、ダミー膜１６からなる独立し
た一対の積層構造をそれぞれ形成したものである。In the first modification, as shown in FIG.
A plurality of lower electrodes 11 are formed on the lower electrode 11, and a pair of independent stacked layers of ferromagnetic films 12 and 13, an insulating layer 14, a ferromagnetic film 15, and a dummy film 16 having the same planar shape are formed on each lower electrode 11. Each of the structures is formed.
【００３７】第２変形例は、図９に示すように、基板１
０上に下部電極１１、強磁性膜１２，１３からなる複数
の積層構造を形成し、各強磁性膜１３上に、同一平面形
状の絶縁層１４、強磁性膜１５及びダミー膜１６からな
る独立した一対の積層構造をそれぞれ形成したものであ
る。In the second modification, as shown in FIG.
On the ferromagnetic film 13, a plurality of laminated structures each including a lower electrode 11, ferromagnetic films 12, 13 are formed, and an insulating layer 14, a ferromagnetic film 15, and a dummy film 16 having the same planar shape are formed on each ferromagnetic film 13. Each of the paired laminated structures is formed.
【００３８】第３変形例は、図１０に示すように、上記
第１変形例の強磁性膜１５（自由磁化層）を下部電極１
１と絶縁層１４と間に配置するとともに、強磁性膜１
２，１３（固定磁化層）を絶縁層１４とダミー膜１６と
の間に配置したものである。この場合、強磁性膜１５を
構成するＣｏ膜を絶縁層１４に接するようにするととも
に、Ｃｏ膜と下部電極１１との間にＮｉＦｅ膜を配置す
るようにする。また、固定磁化層を構成するＮｉＦｅ膜
からなる強磁性膜１３を絶縁層１４に接するようにする
とともに、ＣｏＰｔＣｒ膜からなる強磁性膜１２を絶縁
層１４とダミー膜１６との間に配置するようにする。In the third modification, as shown in FIG. 10, the ferromagnetic film 15 (free magnetic layer) of the first modification is
1 and the insulating layer 14 and the ferromagnetic film 1
2 and 13 (fixed magnetic layers) are arranged between the insulating layer 14 and the dummy film 16. In this case, the Co film constituting the ferromagnetic film 15 is in contact with the insulating layer 14, and the NiFe film is disposed between the Co film and the lower electrode 11. Further, the ferromagnetic film 13 made of a NiFe film constituting the fixed magnetic layer is brought into contact with the insulating layer 14, and the ferromagnetic film 12 made of the CoPtCr film is arranged between the insulating layer 14 and the dummy film 16. To
【００３９】これらの積層構造に関する各種変形例にお
いても、上述した積層構造と同一の材料を用いることが
できるので、それらの詳細な説明は省略する。また、こ
れらの各種変形例においても、上記図４のように、磁気
トンネル接合構造をマトリクス上に配置すると、多数の
磁気トンネル接合構造を直列に接続することができる。The same materials as those of the above-described laminated structure can be used in the various modified examples of the laminated structure, and therefore, detailed description thereof is omitted. Also in these various modified examples, as shown in FIG. 4, when the magnetic tunnel junction structures are arranged on a matrix, a large number of magnetic tunnel junction structures can be connected in series.
【００４０】なお、上記積層構造の各種例においては、
強磁性膜１３の磁化の向きを固定するためにＣｏＰｔＣ
ｒなどの強磁性膜１２を用いたが、強磁性膜１３の磁化
の向きを固定するために、ＲｈＭｎ，ＦｅＭｎ，ＰｔＭ
ｎ等の反強磁性膜を用いることもできる。絶縁層１４の
バリア膜としての信頼性を高めるためには、強磁性膜１
３の表面粗さが少ない方が好ましく、したがって、強磁
性膜１３及び反強磁性膜の膜厚はある程度薄い方が好ま
しい。例えば、強磁性膜１３の膜厚を５〜１０ｎｍに設
定するとともに、反強強磁性膜の膜厚を５０ｎｍ以下に
設定することが好ましい。In various examples of the above-mentioned laminated structure,
In order to fix the magnetization direction of the ferromagnetic film 13, CoPtC
Although the ferromagnetic film 12 such as rMn is used, in order to fix the magnetization direction of the ferromagnetic film 13, RhMn, FeMn, PtM
An antiferromagnetic film such as n can also be used. In order to increase the reliability of the insulating layer 14 as a barrier film, the ferromagnetic film 1
The surface roughness of the ferromagnetic film 13 and the antiferromagnetic film is preferably somewhat small. For example, it is preferable that the thickness of the ferromagnetic film 13 is set to 5 to 10 nm and the thickness of the anti-ferromagnetic film is set to 50 nm or less.
【００４１】反強磁性膜によって磁化の方向が固定され
た強磁性膜１３も、十分に強い外部磁界をかけると、そ
の方向に磁化の向きが変わってしまい、センサとして適
さない。この固定磁化層の磁化の方向を変える外部磁界
（交換結合磁界）の大きさは、反強磁性膜の材料、製造
方法に依存するほかに、強磁性膜と反強磁性膜の膜厚に
も関係し、強磁性膜１３の膜厚が薄いほど、前記外部磁
界（交換結合磁界）の強さは大きくなる。例えば、反強
磁性膜ＲｈＭｎを用いた場合、ＲｈＭｎの膜厚を３０ｎ
ｍ、ＮｉＦｅを用いた強磁性膜１３の膜厚を５ｎｍ程度
に設定すると、前記外部磁界の強さは２００エルステッ
ド程度になる。The ferromagnetic film 13 in which the direction of magnetization is fixed by the antiferromagnetic film, when a sufficiently strong external magnetic field is applied, changes the direction of magnetization in that direction, and is not suitable as a sensor. The magnitude of the external magnetic field (exchange coupling magnetic field) that changes the magnetization direction of the fixed magnetic layer depends on the material and manufacturing method of the antiferromagnetic film, and also on the thickness of the ferromagnetic film and the antiferromagnetic film. In this regard, the strength of the external magnetic field (exchange coupling magnetic field) increases as the thickness of the ferromagnetic film 13 decreases. For example, when the antiferromagnetic film RhMn is used, the thickness of RhMn is set to 30 n.
When the thickness of the ferromagnetic film 13 using m and NiFe is set to about 5 nm, the intensity of the external magnetic field becomes about 200 Oe.
【００４２】また、上記実施形態及び各種変形例に係る
積層構造においては、下部電極１１の材料としてＣｒ又
はＴｉを用いるようにしたが、これに限らず、Ｃｕ，
Ｗ，Ｔａ，Ａｕ，Ｍｏ等の導電性非磁性金属材料を用い
ることができる。また、ダミー膜１６及び上部電極１８
に関しても、Ｃｒ，Ｔｉに加え、前記のような各種導電
性非磁性金属材料を用いることができる。In the laminated structure according to the above-described embodiment and various modifications, Cr or Ti is used as the material of the lower electrode 11, but the material is not limited to this.
A conductive non-magnetic metal material such as W, Ta, Au, and Mo can be used. Also, the dummy film 16 and the upper electrode 18
Also, in addition to Cr and Ti, various conductive non-magnetic metal materials as described above can be used.
【００４３】さらに、上記のように構成した磁気抵抗素
子（磁気センサ）によって外部磁界の方向を検出する装
置及び方法について説明する。図１１に示すように、磁
性材料で構成したギアＧＲの径方向外側にて同ギアＧＲ
の歯に対向して外部磁界の発生源である磁石ＭＧを配置
すると共に、同磁石ＭＧとギアＧＲの歯との間に磁気抵
抗素子ＴＭＲを配置する。この場合、磁気抵抗素子ＴＭ
Ｒの抵抗変化の最も大きな領域を利用するために、外部
磁界の向きが磁気抵抗素子ＴＭＲの固定磁化の向きとほ
ぼ直交する近辺で変化するように、すなわち図６(Ａ)及
び図１２の１８０度近辺で変化するように、磁気抵抗素
子ＴＭＲを配置する。そして、磁気抵抗素子ＴＭＲに一
定の電流を流しておくか、両端に電圧を印加しておき、
電圧値の変化、電流値の変化を検出する。Further, an apparatus and a method for detecting the direction of an external magnetic field using the magnetoresistive element (magnetic sensor) configured as described above will be described. As shown in FIG. 11, the gear GR made of a magnetic material is disposed radially outside the gear GR.
A magnet MG, which is a source of an external magnetic field, is arranged to face the teeth, and a magnetoresistive element TMR is arranged between the magnet MG and the teeth of the gear GR. In this case, the magnetoresistive element TM
In order to use the region where the resistance change of R is the largest, the direction of the external magnetic field changes so as to change near the direction substantially perpendicular to the fixed magnetization direction of the magnetoresistive element TMR, that is, 180 in FIGS. The magnetoresistive element TMR is arranged so as to change in the vicinity of degrees. Then, a constant current is applied to the magneto-resistance element TMR or a voltage is applied to both ends,
Detects changes in voltage and current values.
【００４４】これによれば、ギアＧＲが回転すると、図
１１(Ａ)〜(Ｃ)にて矢印Ｈで示すように、磁気抵抗素子
ＴＭＲを通過する外部磁界の方向が変化し、同外部磁界
の方向の変化を磁気抵抗素子ＴＭＲの電圧値（抵抗値）
の変化により外部磁界の方向すなわちギアＧＲの回転角
を検出することができる。According to this, when the gear GR rotates, the direction of the external magnetic field passing through the magnetoresistive element TMR changes as shown by the arrow H in FIGS. Changes in the direction of the resistance of the magnetoresistive element TMR
, The direction of the external magnetic field, that is, the rotation angle of the gear GR can be detected.
【図１】 本発明の一実施形態に係る磁気抵抗素子（磁
気センサ）の一部を示す概略断面図である。FIG. 1 is a schematic sectional view showing a part of a magnetoresistive element (magnetic sensor) according to an embodiment of the present invention.
【図２】 前記図１の磁気抵抗素子の層間絶縁膜及び基
板を省略した同素子の概略平面図である。FIG. 2 is a schematic plan view of the magnetoresistive element of FIG. 1 from which an interlayer insulating film and a substrate are omitted.
【図３】 前記図１の磁気抵抗素子の固定磁化層を形成
する強磁性膜の概略平面図である。FIG. 3 is a schematic plan view of a ferromagnetic film forming a fixed magnetization layer of the magnetoresistive element of FIG. 1;
【図４】 複数の磁気トンネル接合構造をマトリクス状
に配置した磁気抵抗素子の概略平面図である。FIG. 4 is a schematic plan view of a magnetoresistive element in which a plurality of magnetic tunnel junction structures are arranged in a matrix.
【図５】 回転する外部磁界に対する磁気抵抗素子（磁
気センサ）の特性を測定するための装置の模式図であ
る。FIG. 5 is a schematic diagram of an apparatus for measuring characteristics of a magnetoresistive element (magnetic sensor) with respect to a rotating external magnetic field.
【図６】 (Ａ)は外部磁界の回転に対する磁気抵抗素子
（磁気センサ）の電圧の変化を示すグラフであり、(Ｂ)
は前記(Ａ)の一部を拡大したグラフである。FIG. 6A is a graph showing a change in voltage of a magnetoresistive element (magnetic sensor) with respect to rotation of an external magnetic field, and FIG.
Is a graph in which a part of the above (A) is enlarged.
【図７】 (Ａ)(Ｂ)は、アスペクト比及び固定磁化の向
きを異ならせた場合における磁気ヒステリシスによる角
度差の変化を示すグラフである。FIGS. 7A and 7B are graphs showing changes in the angle difference due to magnetic hysteresis when the aspect ratio and the direction of the fixed magnetization are changed.
【図８】 積層構造の第１変形例を示す磁気抵抗素子の
断面図である。FIG. 8 is a sectional view of a magnetoresistive element showing a first modification of the laminated structure.
【図９】 積層構造の第２変形例を示す磁気抵抗素子の
断面図である。FIG. 9 is a sectional view of a magnetoresistive element showing a second modification of the laminated structure.
【図１０】 積層構造の第３変形例を示す磁気抵抗素子
の断面図である。FIG. 10 is a sectional view of a magnetoresistive element showing a third modification of the laminated structure.
【図１１】 磁気抵抗素子（磁気センサ）による外部磁
界の方向を検出するための装置及び方法を概略的に示す
概略図である。FIG. 11 is a schematic diagram schematically showing an apparatus and a method for detecting the direction of an external magnetic field by a magnetoresistive element (magnetic sensor).
【図１２】 外部磁界の回転に対する磁気抵抗素子（磁
気センサ）の電圧の変化状態を説明するためのグラフで
ある。FIG. 12 is a graph illustrating a change state of a voltage of a magnetoresistive element (magnetic sensor) with respect to rotation of an external magnetic field.
１０…基板、１１…下部電極、１２，１３，１５…強磁
性膜、１４…絶縁層、１６…ダミー膜、１７…層間絶縁
膜、１８…上部電極、ＴＭＲ…磁気抵抗素子（磁気セン
サ）、ＨＬ…ヘルムホルツコイル、ＧＲ…ギア、ＭＧ…
磁石。DESCRIPTION OF SYMBOLS 10 ... board | substrate, 11 ... lower electrode, 12, 13, 15 ... ferromagnetic film, 14 ... insulating layer, 16 ... dummy film, 17 ... interlayer insulating film, 18 ... upper electrode, TMR ... magnetoresistive element (magnetic sensor), HL: Helmholtz coil, GR: Gear, MG ...
magnet.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 山下 正芳 静岡県浜松市中沢町10番１号 ヤマハ株式 会社内 (72)発明者 金子 明 静岡県浜松市中沢町10番１号 ヤマハ株式 会社内 Ｆターム(参考） 2G017 AA03 AD55 AD63 AD65 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Masayoshi Yamashita 10-1 Nakazawa-cho, Hamamatsu-shi, Shizuoka Prefecture Inside Yamaha Corporation (72) Inventor Akira Kaneko 10-1 Nakazawa-cho, Hamamatsu-shi, Shizuoka Prefecture Yamaha Corporation F Term (reference) 2G017 AA03 AD55 AD63 AD65
Claims (7)
の向きを自由に変化させるようにした自由磁化層との間
に絶縁層を挟んで構成した磁気トンネル接合構造を有
し、前記自由磁化層を長方形状に形成するとともに、前
記固定磁化層の磁化の向きを前記自由磁化層の短辺方向
と一致させたことを特徴とする磁気抵抗素子。1. A magnetic tunnel junction structure comprising an insulating layer interposed between a fixed magnetization layer having a fixed magnetization direction and a free magnetization layer having a magnetization direction freely changed, A magnetoresistive element, wherein the free magnetic layer is formed in a rectangular shape, and the direction of magnetization of the fixed magnetic layer is made to coincide with the short side direction of the free magnetic layer.
て、前記自由磁化層の短辺の長さに対する長辺の長さの
比を４以上に設定したことを特徴とする磁気抵抗素子。2. A magnetoresistive element according to claim 1, wherein a ratio of a length of a long side to a length of a short side of said free magnetic layer is set to 4 or more.
抗素子において、前記固定磁化層を、前記絶縁層に接す
る第１強磁性膜と、前記第１強磁性膜の前記絶縁層と反
対側の面に接して前記第１強磁性膜の磁化の方向を固定
するための第２強磁性膜とで構成した磁気抵抗素子。3. The magnetoresistive element according to claim 1, wherein said fixed magnetic layer is formed of a first ferromagnetic film in contact with said insulating layer and said insulating layer of said first ferromagnetic film. A magnetoresistive element comprising: a second ferromagnetic film for fixing a direction of magnetization of the first ferromagnetic film in contact with an opposite surface.
て、前記第２強磁性膜をＣｏを含む合金で構成した磁気
抵抗素子。4. The magnetoresistive element according to claim 3, wherein said second ferromagnetic film is made of an alloy containing Co.
抗素子において、前記固定磁化層を、前記絶縁層に接す
る強磁性膜と、前記強磁性膜の前記絶縁層と反対側の面
に接して前記強磁性膜の磁化の方向を固定するための反
強磁性膜とで構成した磁気抵抗素子。5. The magnetoresistive element according to claim 1, wherein the fixed magnetic layer is formed by a ferromagnetic film in contact with the insulating layer, and a surface of the ferromagnetic film opposite to the insulating layer. And an antiferromagnetic film for fixing the direction of magnetization of the ferromagnetic film in contact with the ferromagnetic film.
か一つに記載の磁気抵抗素子において、前記固定磁化
層、絶縁層及び自由磁化層からなる磁気トンネル接合構
造を複数直列に接続した磁気抵抗素子。6. A magnetoresistive element according to claim 1, wherein a plurality of magnetic tunnel junction structures comprising said fixed magnetic layer, insulating layer and free magnetic layer are connected in series. Magnetoresistive element.
か一つに記載の磁気抵抗素子は、前記固定磁化層、絶縁
層及び自由磁化層の積層方向と直交する面内を通過する
外部磁界の方向を検出するものである。7. The magnetoresistive element according to claim 1, wherein the magnetoresistive element passes through a plane orthogonal to the lamination direction of the fixed magnetic layer, the insulating layer, and the free magnetic layer. It detects the direction of the external magnetic field.
Priority Applications (1)
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|---|---|---|---|
| JP2000024474A JP2001217478A (en) | 2000-02-01 | 2000-02-01 | Magnetic resistance element |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000024474A JP2001217478A (en) | 2000-02-01 | 2000-02-01 | Magnetic resistance element |
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|---|---|
| JP2001217478A true JP2001217478A (en) | 2001-08-10 |
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ID=18550455
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006508528A (en) * | 2002-11-27 | 2006-03-09 | ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツング | Magnetoresistive sensor element and method for reducing angular error of magnetoresistive sensor element |
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2000
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|---|---|---|---|---|
| JP2006508528A (en) * | 2002-11-27 | 2006-03-09 | ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツング | Magnetoresistive sensor element and method for reducing angular error of magnetoresistive sensor element |
| JP2011149949A (en) * | 2002-11-27 | 2011-08-04 | Robert Bosch Gmbh | Magnetoresistive sensor element and method for reducing angular error of magnetoresistive sensor element |
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| US7786725B2 (en) | 2005-08-31 | 2010-08-31 | Mitsubishi Electric Corporation | Magnetic field detection apparatus for detecting an external magnetic field applied to a magnetoresistance effect element, and method of adjusting the same |
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| JP2011027683A (en) * | 2009-07-29 | 2011-02-10 | Tdk Corp | Magnetic sensor |
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