JP4023997B2 - Thin film magnetic field sensor - Google Patents

Thin film magnetic field sensor Download PDF

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Publication number
JP4023997B2
JP4023997B2 JP2000367822A JP2000367822A JP4023997B2 JP 4023997 B2 JP4023997 B2 JP 4023997B2 JP 2000367822 A JP2000367822 A JP 2000367822A JP 2000367822 A JP2000367822 A JP 2000367822A JP 4023997 B2 JP4023997 B2 JP 4023997B2
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thin film
gap
terminal
soft magnetic
magnetic field
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JP2002131407A5 (en
JP2002131407A (en
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伸聖 小林
健 矢野
繁弘 大沼
健 増本
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THE FOUDATION: THE RESEARCH INSTITUTE FOR ELECTRIC AND MAGNETIC MATERIALS
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THE FOUDATION: THE RESEARCH INSTITUTE FOR ELECTRIC AND MAGNETIC MATERIALS
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Priority to EP01978911A priority patent/EP1329735B1/en
Priority to CNB018032648A priority patent/CN100403048C/en
Priority to KR1020027008326A priority patent/KR100687513B1/en
Priority to DE60139017T priority patent/DE60139017D1/en
Priority to AT01978911T priority patent/ATE434192T1/en
Priority to PCT/JP2001/009385 priority patent/WO2002037131A1/en
Priority to TW090126413A priority patent/TW550394B/en
Publication of JP2002131407A publication Critical patent/JP2002131407A/en
Priority to US10/225,794 priority patent/US6642714B2/en
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Description

【０００１】
【産業上の利用分野】
本発明は、空間中の磁界を測定する薄膜磁界センサに関し、巨大磁気抵抗薄膜、例えばナノグラニュラー巨大磁気抵抗効果薄膜を用いて、磁界を精密に測定するための薄膜磁界センサに関するものである。
【０００２】
【従来の技術】
図１は、特開平１１−８７８０４号公報および特開平１１−２７４５９９に記載された磁界センサを示す。図中、巨大磁気抵抗薄膜と書かれた部分は、１０ｋＯｅの磁界の印加に対して、約１０％の電気抵抗変化を示す金属−絶縁体ナノグラニュラー巨大磁気抵抗薄膜である。この例のように、巨大磁気抵抗薄膜の場合には、一般の磁気抵抗効果材料に比して電気抵抗値の変化幅は大であるが、前記の通り電気抵抗変化を起こさせるための印加磁界は大きく、巨大磁気抵抗薄膜のみを単独で用いる場合には、一般に磁界センサとして利用されるような小さな磁界での電気抵抗値変化は期待できない。図１の構成は、それを補うものである。すなわち、軟磁性薄膜は周辺の磁束を集める役割を担っており、適切な軟磁性薄膜の寸法を選定することにより、原理的には、軟磁性薄膜周辺の磁界の大小に拘わらず、巨大磁気抵抗薄膜部分に対して軟磁性薄膜の飽和磁束密度以内で、いかようにも大きな磁束密度を印加することが可能である。また、図１の構成を電気抵抗の観点から見ると、軟磁性薄膜間の電気抵抗値は、軟磁性薄膜部分と巨大磁気抵抗薄膜部分の電気抵抗値の和になっているが、巨大磁気抵抗薄膜の電気比抵抗の値は、軟磁性薄膜のそれに比して１００倍以上大きいため、実質的に軟磁性薄膜間の電気抵抗値は巨大磁気抵抗薄膜部分の値と等しい。つまり、軟磁性薄膜間の電気抵抗値には、巨大磁気抵抗薄膜の電気抵抗値変化が直接現れる。図２は、このような図１の構成の電気抵抗変化の例を示すものであり、数Ｏｅの小さな磁界において約６％の電気抵抗値変化を実現している。
【０００３】
【発明が解決しようとする課題】
しかし、本発明が目的とする、巨大磁気抵抗薄膜の電気抵抗測定値をもとにして、印加された磁界の絶対値を計測する磁界センサを実現する場合には、図１の構成では、大きな問題があることが判明した。それは、巨大磁気抵抗薄膜の温度による電気抵抗値変化の問題である。前記の通り、図１の構成の場合には検出したい磁界の大小に対しては選択の余地がある。しかし、いかに感度を高めたとしても、それは感動する磁界に対する選択であり、巨大磁気抵抗薄膜の持つ電気抵抗変化以上の変化幅を得ることは、原理的にできない。現実に図１の構成の場合の電気抵抗変化幅は、他の要因を含めて更に圧縮されてほぼ６％程度となっている。この６％の電気抵抗値変化に対して、巨大磁気抵抗薄膜の温度による変化があれば、その電気抵抗値変化分だけは印加された磁界を推定する場合の不確定要素となる。図３は温度特性の実例を示している。この図から明らかな通り、巨大磁気抵抗薄膜の温度による電気抵抗値変化は、磁界印加による抵抗変化よりむしろ大であり、図１の構成のままでは、磁界の絶対値を計測する磁界センサとしては利用が難しい。
【課題を解決するための手段】
【０００４】
本発明の特徴とするところは、下記の点にある。第１発明は、所定の空隙長を持つ空隙によって２分割され、所定の膜厚および空隙に接する所定の幅を持つ軟磁性薄膜１、その空隙を埋めるように形成された巨大磁気抵抗薄膜２、２分割された軟磁性薄膜１の各々に電気的に接続された端子３および端子４、前記空隙長と実質的に等しい空隙長を持つ空隙によって２分割され、前記膜厚と実質的に等しい膜厚、および前記空隙に接する幅と実質的に等しい幅を持つ導体膜６、その空隙を埋めるように形成された巨大磁気抵抗薄膜７、および２分割された導体膜６の各々に電気的に接続された端子８および端子９からなり、端子３および端子４と端子８および端子９は、各々ブリッジ回路の２つのアームを形成することを特徴とする薄膜磁界センサを提供する。
【０００５】
第２発明は、所定の空隙長を持つ空隙によって２分割され、所定の膜厚および空隙に接する所定の幅を持つ軟磁性薄膜１、その空隙を埋めるように形成された巨大磁気抵抗薄膜２、２分割された軟磁性薄膜１の各々に電気的に接続された端子３および端子４、前記空隙長と実質的に等しい空隙長を持つ空隙によって２分割され、前記膜厚と実質的に等しい膜厚および前記空隙に接する幅と実質的に等しい幅を持つ導体膜６、その空隙を埋めるように形成された巨大磁気抵抗薄膜７、２分割された導体膜６の各々に電気的に接続された端子８および端子９、前記空隙長と実質的に等しい空隙長を持つ空隙によって２分割され、前記膜厚と実質的に等しい膜厚および前記空隙に接する幅と実質的に等しい幅を持つ軟磁性薄膜２１、その空隙を埋めるように形成された巨大磁気抵抗薄膜２２、２分割された軟磁性薄膜２１の各々に電気的に接続された端子２３および端子２４、前記空隙長と実質的に等しい空隙長を持つ空隙によって２分割され、前記膜厚と実質的に等しい膜厚および前記空隙に接する幅と実質的に等しい幅を持つ導体膜２６、その空隙を埋めるように形成された巨大磁気抵抗薄膜２７、および２分割された導体膜２６の各々に電気的に接続された端子２８および端子２９からなり、端子３および端子４、端子８および端子９、端子２３および端子２４、端子２８および端子２９は、各々ブリッジ回路の４つのアームを形成することを特徴とする薄膜磁界センサを提供する。
【０００６】
第３発明は、所定の空隙長を持つ空隙によって２分割され、所定の膜厚および空隙に接する所定の幅を持つ軟磁性薄膜１、その空隙を埋めるように形成された巨大磁気抵抗薄膜２、２分割された軟磁性薄膜１の各々に電気的に接続された端子３および端子４、前記空隙長と実質的に等しい空隙長を持つ空隙によって２分割され、前記膜厚と実質的に等しい膜厚、および前記空隙に接する幅と実質的に等しい幅を持つ軟磁性薄膜３１、その空隙を埋めるように形成された巨大磁気抵抗薄膜３２、および２分割された軟磁性薄膜３１の各々に電気的に接続された端子３３および端子３４からなり、端子３および端子４、端子３３および端子３４は、各々ブリッジ回路の２つのアームを形成し、且つまた軟磁性薄膜３１の平面上の面積は、軟磁性薄膜１の平面上の面積に比して１／１０以下であることを特徴とする薄膜磁界センサを提供する。
【０００７】
第４発明は、空隙に接する線と並行な線に沿って測った軟磁性薄膜１の幅寸法の少なくとも一部は、その軟磁性薄膜１が空隙に接する線の幅よりも大であることを特徴とする第１発明ないし第３発明のいずれかに記載の薄膜磁界センサを提供する。
【０００８】
第５本発明は、軟磁性薄膜１の磁気特性は一軸異方性であって、その磁化容易軸方向は、実質的に、空隙に接する線と並行な方向であることを特徴とする第１発明ないし第３発明のいずれかに記載の薄膜磁界センサを提供する。
【０００９】
【作用】
本発明の作用は下記の通りである。
第一発明の構成は、巨大磁気抵抗薄膜の持つ電気抵抗値変化の中で、温度、湿度および経時的な原因による変化を除外し、磁界による変化のみを抽出することによって、精度の高い磁界センサを実現するものである。すなわち、巨大磁気抵抗薄膜および構造を同一とする２系統の素子によるブリッジ回路を形成し、その中の一方の素子は巨大磁気抵抗薄膜の両側に軟磁性薄膜を配置することによって磁界に対する感度を高め、他方の素子は巨大磁気抵抗薄膜をそのまま用いることにより磁界に対する感度を実質的に零としている。ブリッジ回路の出力電圧はこれら素子の電気抵抗値の差に比例するものであるから、結果的に、巨大磁気抵抗薄膜の持つ温度変化を始めその他の湿度、経時変化等の変動要因は出力電圧より除外され、磁界による電気抵抗値変化のみが出力に現れる。そのため磁界の絶対値の検出が精度良く実現可能になり、また同時に極めて小さな磁界の検出も可能になる。
【００１０】
第２発明の構成は、さらに精度が高く、且つ磁界感度の高い薄膜磁界センサを実現するものである。すなわち、巨大磁気抵抗薄膜の両側に軟磁性薄膜を配置した素子と、巨大磁気抵抗薄膜の両側に導体膜を配置した素子を、各々２個用いてブリッジ回路を構成することによって、ブリッジ出力電圧は、第１発明の構成よりも更に２倍大きくすることが可能となり、より精度が高く、且つより磁界感度の高い薄膜磁界センサが実現可能となる。
【００１１】
第３発明の構成は、利用する材料の観点から、薄膜磁界センサの精度を更に高めるものである。すなわち、ブリッジを構成する素子中の巨大磁気抵抗薄膜部分の材質・構造が全く同じでも、巨大磁気抵抗薄膜を挟んでいる材料が異なる場合には、接触電位差、あるいは熱起電力等により微小な電気抵抗値の違いが出る場合がある。第３発明の構成によれば、これ等の問題を含めて、２つの構造の磁界印加による抵抗変化以外の要因による巨大磁気抵抗薄膜の電気抵抗値変化を、厳密な意味で相殺することができ、これにより更に精度の高い薄膜磁界センサが実現できる。
【００１２】
第４発明の構成は、構造の面から、より小型で高精度の薄膜磁界センサを実現するものである。磁界センサとしての感度を高く、しかも、形状的に小型化するためには、巨大磁気抵抗薄膜の両側に軟磁性薄膜を配置した構造において、軟磁性薄膜の有効面積を一定とした上で、軟磁性薄膜部分の小型化を計る必要がある。第４発明の構成により、感度が高く、また形状的により小型の磁界センサの実現が可能になる。
【００１３】
第５発明の構成は、残留磁化の面から薄膜磁界センサの精度を、さらに高めるものである。つまり、印加された磁界の計測を完了し、外部磁界が取り去られた後で、軟磁性薄膜中に磁化が残留する場合には、この残留磁化は、巨大磁気抵抗薄膜に対して外部磁界印加と同様の作用を及ぼすことになり、磁界の検出精度の低下を来たす。このため、第５発明の構成では、軟磁性薄膜を巨大磁気抵抗薄膜の検出磁界と直交する方向に磁化させることにより、軟磁性薄膜中の残留磁化を減らして、より高精度に磁界を計測することができる。
【００１４】
【実施例】
以下、図面に基づき、本発明の種々の実施形態につき説明する。尚、各図において同一の要素は同じ番号を付してあり、説明の重複を避けている。
【００１５】
［実施例１］
図４は、本発明の第１の実施例を示す。この図および以降の図では、理解を助けるため、巨大磁気抵抗薄膜の部分を点々の印、軟磁性薄膜の部分を斜め線、導体薄膜部分を白ぬき、として区別している。５は、軟磁性薄膜１、巨大磁気抵抗薄膜２および電気端子３、４を含めた素子を表しており、公知技術である図１の構成と同一である。素子５の作用についての記述は本文中の段落０００２に述べたので、ここでは重複を避けて本発明の具体内容の記述のみを行う。１は軟磁性薄膜で、１５ｋＧ以上の高い飽和磁束密度と、０．５Ｏｅ以下の低い保磁力を持つパーマロイである。その他の材料を含めて、軟磁性薄膜１の具体的な材料名およびその代表特性は表１に示す。
【００１６】
【表１】

Figure 0004023997
【００１７】
軟磁性薄膜１の厚さはｔ＝１μｍである。軟磁性薄膜１には、空隙長ｇで示した空隙が形成されている。空隙長ｇの寸法はｇ＝１μｍである。空隙に接する軟磁性薄膜１の幅ｗの寸法はｗ＝１００μｍである。その軟磁性薄膜１の空隙を埋めるように巨大磁気抵抗薄膜２が形成されている。巨大磁気抵抗薄膜２の材質は、Ｃｏ３９Ｙ１４Ｏ４７である。この材料を含め、巨大磁気抵抗薄膜２として可能な材料名およびその代表特性は表２に示す。
【００１８】
【表２】
Figure 0004023997
【００１９】
ここでの軟磁性薄膜１の厚さｔ、空隙長ｇおよび空隙に接する軟磁性薄膜１の幅ｗの寸法については、磁気的な条件と電気的な条件の両面からの要求される特性を満たすように選択する必要があるが、本発明の特徴は広い範囲に亙って目的とする性能を得る事にある。すなわち、寸法の選択範囲は大変広い。磁気的な条件としては、空隙長ｇが広すぎる場合、例えば軟磁性薄膜の厚さｔの数倍以上の場合には、軟磁性薄膜１が周辺の磁束を集めて空隙部分に磁束を十分に集中させる事が出来ない。一方、軟磁性薄膜の厚さｔについては、機能上はいかに厚くても本発明の機能を発揮するが、軟磁性薄膜を形成する装置の持つ単位時間当たりの堆積能力、あるいは軟磁性薄膜が基板に形成された場合の応力により、軟磁性薄膜が基板から剥離するなど、現実的な制約条件で厚さの限界は決まってくる。逆に軟磁性薄膜の厚さｔが１０ｎｍ以下の場合には、軟磁性薄膜の磁気特性が劣化するので、実質的に１０ｎｍが厚さの下限である。電気的な条件としては、軟磁性薄膜１の幅ｗは、磁気センサの小型化および電気抵抗の絶対値として周辺回路が扱いやすい値、例えば数１０ｋΩから数１００ＭΩの範囲となることを勘案して設定する必要がある。電気抵抗の絶対値は、巨大磁気抵抗薄膜の電気比抵抗および空隙長ｇに比例し、軟磁性薄膜の幅ｗおよび軟磁性薄膜の厚さｔに反比例するので、比較的設計での自由度は大であり、具体的な軟磁性薄膜の幅ｇは、最大数ｍｍから最小数μｍの広い範囲での実現の可能性がある。
【００２０】
空隙を挟んで２分割された両側の軟磁性薄膜１には、各々Ｃｕによる電気端子３および４が接続されている。この電気端子部分の材質は、磁気的には大きな影響を持たないので、電気的な導通性を中心として決定して良く、軟磁性薄膜の材質を共通に利用することも可能であり、また実際に外部との接続に供せられる部分にのみ、表面にＣｕ膜を形成すること等も可能である。５は軟磁性薄膜１、巨大磁気抵抗薄膜２、ならびに電気端子３および４を含めた素子を表している。電気端子３と４の間の電気抵抗値をＲａと表す。図５は、軟磁性薄膜１の長さ寸法Ｌをパラメータとして、素子５の印加磁界と電気抵抗値変化の関係の一例を示したものであり、長さ寸法Ｌを大きくすることにより、より小さな磁界において感動させることが可能であることが分かる。図６は素子５の温度による抵抗値変化を示したものである。図５の印加磁界と電気抵抗値との関係は、印加磁界の絶対値を取れば、ある大きさの磁界まではほぼリニアな変化になっている。また、図６の温度と電気抵抗値の変化について、室温付近でリニアな関係とみなす。そこで、印加磁界零で、且つ温度２２℃の場合の抵抗値をＲ０とし、印加磁界の絶対値をＨ、温度をＴとすれば、抵抗値Ｒａは式１のように表現できる。
【００２１】
Ｒａ＝Ｒ０（１＋ｒＭＨ＋ｒＴ（Ｔ−２５）） （１）
ここに、ｒＭは電気抵抗値の印加磁界による変化の微係数、ｒＴは電気抵抗値の温度係数である。表３は、軟磁性薄膜の各長さ寸法ＬについてｒＭの値および式１が成立する磁界Ｈの範囲、およびｒＴの値を示している。
【００２２】
【表３】
Figure 0004023997
【００２３】
６は、軟磁性薄膜１と実質的に同じ厚さｔ´を持った導体膜である。導体膜６の材料はＣｕである。Ｃｕ材料は、極く弱い反磁性を示すがほとんど磁気的には透明とみなされる。導体膜６には軟磁性薄膜１の空隙長ｇと実質的に等しい寸法の空隙長ｇ′が形成されている。空隙に接する導体膜６の幅ｗ´は、実質的に空隙に接する軟磁性薄膜１の幅ｗと同一である。素子５のＬに対応する長さ寸法は任意である。その導体膜６の空隙を埋めるように、巨大磁気抵抗薄膜７が形成されている。巨大磁気抵抗薄膜７の材質は、巨大磁気抵抗薄膜２と同一である。空隙を挟んで２分割された両側の導体膜６には、各々電気端子８および９が接続されている。１０は、導体膜６、巨大磁気抵抗薄膜７、および電気端子８、９を含めた素子を表している。電気端子８、９間の電気抵抗をＲｂと表す。
【００２４】
素子１０については、導体膜６が磁気的な作用を持たないため、巨大磁気抵抗薄膜７に印加される磁束密度は、巨大磁気抵抗薄膜７の置かれる環境の磁束密度そのものである。図７は、印加磁界によるＲｂの変化を示すもので、実質的に印加磁界による電気抵抗値変化は零とみなされる。一方、温度に対する変化としては、図６に示す温度係数と同じ温度係数を示す。従って、式１に対応して素子１０の場合の電気抵抗値Ｒｂの式を示すと、式２のようになる。
Ｒｂ＝Ｒ ０ （１＋ｒ Ｔ （Ｔ−２５）） （２）
【００２５】
１１は電気抵抗値Ｒｃを持つ第１の抵抗器であり、第１の抵抗器１１には電気端子１２および１３が接続されている。１４は電気抵抗値Ｒｄを持つ第２の抵抗器である。第２の抵抗器１４には、電気端子１５および１６が接続されている。第１の抵抗器と第２の抵抗器については、それ等の間で抵抗値およびその温度係数は、精密に一致したものを利用する。式１、２と同様にして、電気抵抗の温度係数をｒＴ′とすれば、式３および４を得る。
Ｒｃ＝Ｒ ０ （１＋ｒ Ｔ ´（Ｔ−２５）） （３）
Ｒｄ＝Ｒ ０ （１＋ｒ Ｔ ´（Ｔ−２５）） （４）
【００２６】
端子４、８および２０間、端子３、１２および１７間、端子９、１６および１８間、端子１３、１５および１９間は電気的に相互接続されている。図８は、図４の構成を電気的等価回路として表したものであり、全体として一つのブリッジ回路を形成している。素子５および素子１０は、ブリッジ回路の２つのアームを形成している。端子１７と１８間には駆動電圧が印加され、端子１９、２０間にはブリッジの出力電圧が現れる。図８の回路において、端子１７、１８間に電圧Ｖ０を印加した場合に、端子１９、２０間に現れる電圧Ｖ２は、式５で表される。
Ｖ ２ ＝（ＲａＲｄ−ＲｂＲｃ）Ｖ ０ ／（（Ｒａ＋Ｒｂ）・（Ｒｃ＋Ｒｄ）） （５）
【００２７】
式５のＲａ、Ｒｂ、Ｒｃ、Ｒｄに各々式１、２、３、４を代入し、２次の微小量を省略すれば、Ｖ２の温度に関係する項はすべて相殺され、式６を得る。
Ｖ ２ ＝ｒ Ｔ ＨＶ ０ ／４ （６）
【００２８】
ここに、Ｖ０、ｒＴ、Ｒ０はあらかじめ決定できる定数であり、Ｖ２の測定値を得れば、目的とする磁界は式７のように決定できる。
Ｈ＝４Ｖ ２ ／（Ｖ ０ ｒ Ｔ ） （７）
【００２９】
ブリッジ回路出力Ｖ２として、Ｖ０に対してどの程度のレベルまで安定に検出可能かは、ブリッジ回路出力電圧の増幅器の安定性等で決定されるが、一般にＶ２／Ｖ０＝１ｘ１０−５は容易に実現可能である。従って、式７において、Ｖ２／Ｖ０＝１ｘ１０−５および表３のｒＴの値を代入すれば、本発明によって可能な磁界の分解能を得る。結果は表４の通りである。
【００３０】
【表４】
Figure 0004023997
【００３１】
表４の分解能は、従来技術のＦｌｕｘＧａｔｅセンサの分解能に匹敵する。このＦｌｕｘＧａｔｅセンサは、磁性材料の飽和特性を利用するもので、センサ構造としてもまた周辺回路の構成としてもかなり複雑でまた大型のものである。本発明の構成は、これらの磁界センサに比して極めて簡単、且つ小型軽量であり、本発明の効用は極めて高い。
【００３２】
［実施例２−１］
図９は、本発明の第２の実施例の一つを示す。図中、各々、素子２５は、図４で述べた素子５と、素子３０は素子１０と同等の素子である。全体の回路としては、素子２５が第１の抵抗器を、素子３０が第２の抵抗器をそれぞれ置き換えた形になっている。図９を等価回路として表せば、全体として図８に示した回路と同じ回路となるが、図９の場合は、Ｒｄ＝ＲａおよびＲｃ＝Ｒｂが成立している。式６と同じく式５に、式１、２を代入すれば、式８を得る。
Ｖ ２ ＝ｒ Ｔ ＨＶ ０ ／２ （８）
【００３３】
ここに式８の値は式６の２倍になっている。従って、図９の構成によれば、図４の構成に比してより正確な磁界の大きさの推定が可能であり、また検出可能な磁界の分解能も更に２倍まで高めることができる。
【００３４】
［実施例２−２］
図１０は、本発明の第２の実施例の他の一つを示す。図１０では、素子５および素子２５を並行して配置し、それ等の間に素子１０および素子３０を配置することにより、全体として占有面積の有効利用を計っている。また、端子４と端子８、端子２４と端子２８、および端子３と端子９、端子２３と端子２９は各々共通になっており、これ等の端子間の接続を省略して構造の簡単化を計っている。外部回路への接続端子である１７、１８、１９、２０については、端子３と９、端子２３と２９および端子４と８、端子２４および２８に直接接続はされていないが、素子５および素子２５を通して電気的に接続されており、電気機能的には図６と同様の機能を持っている。図１０の場合には、巨大磁気抵抗薄膜の置かれている角度が、素子５と素子１０および素子２５と素子３０とで直交している。素子１０および素子３０については、図７に示した通り、磁界に対する感度はほとんど零であるが、図１０のように配置することにより、素子５の長手方向に加えられた磁界に対して更に厳密に素子１０および素子３０の電気抵抗変化を零とすることができる。
【００３５】
［実施例３］
図１１は、本発明の第３の実施例を示す。この実施例の第１実施例との違いは、図４で示した６の導体膜として１の軟磁性薄膜と共通の材料を使用している事である。図４では、素子５および素子１０の持つ電気抵抗変化の中で、磁界による変化以外のものをできるだけ等しくし、ブリッジ回路において相殺させることが必要である。このためには、先ず、巨大磁気抵抗薄膜そのものの材質、構造を共通化することであるが、巨大磁気抵抗薄膜そのものが全く同じであっても、それに接触する材料によっては微細な電気抵抗値の違いが出る可能性がある。その原因となるのは、接触電位差、あるいは熱起電力等である。図１１に示す実施例３では、巨大磁気抵抗薄膜に接触させる材質を、素子５と素子３５で共通の軟磁性薄膜とすることにより、この問題を回避している。しかし、素子３５の軟磁性薄膜３１の寸法を大きくすると、必然的に巨大磁気抵抗薄膜３２に加わる磁束密度も大きくなり、素子５と素子３２の抵抗値の差としての磁界センサの感度を低下させてしまう。実施例３では、素子３５の軟磁性薄膜３１の面積を、素子５の軟磁性薄膜１の面積の１／１０以下とすることで、この問題を回避している。この構成によれば、素子３５の導体部分が非磁性体である場合のブリッジ出力電圧に対し、少なくとも９０％以上の出力電圧を確保でき、しかも磁界印加以外の要因による抵抗の変化を、素子５と素子３５で厳密に相殺することができ、高精度の薄膜磁界センサの実現が可能になる。
【００３６】
［実施例４］
図１２は、本発明の第４の実施例を示す。実施例１において、素子５については、軟磁性薄膜のＬ寸法を大きくすることにより、感動する磁界の感度を高められることを述べた。軟磁性薄膜１の持つ機能は、周辺の磁束を集めて巨大磁気抵抗薄膜部分に集中させることであるが、周辺の磁束を集める機能は、ほぼ軟磁性薄膜の面積に比例する。従って、図４に示す構成の場合には、小さな磁界での感度を持たせるためには、どうしてもＬ寸法を大きくする必要があり、磁界センサの全体の寸法が大きくなってしまうことは避けられない。図１２の構成によれば、軟磁性薄膜が巨大磁気抵抗薄膜と接する幅ｗに比して大きなｗｘの幅の部分を設けることにより、軟磁性薄膜の占有面積の有効利用を計り、全体として小型でしかも磁界感度の高い磁気センサが実現できる。
【００３７】
［実施例５］
図１３は本発明の第５の実施例である。軟磁性薄膜では、外部磁界が加わっても、外部磁界を除いた後は磁化が残留し難いが、保磁力Ｈｃの範囲で、磁化が残留してしまう可能性がある。この残留磁化は、検出する磁界の直接誤差となるものであるから、可及的に残留磁化のない材料が望ましい。表１に示した通りＣｏ７７Ｆｅ５Ｓｉ９Ｂ ９ 材料は、パーマロイに比しても１／６程度の低いＨｃを有し、この値は磁化困難軸方向に励磁した場合に得られる。一般的に、一軸異方性を有する磁性材料の困難軸方向の磁化過程は磁化回転によるため、ヒステリシスは発生せず、Ｈｃはほぼ零となる。したがって、困難軸方向では残留磁化は発生しない。本発明の第５の構成によれば、一軸異方性を有する材料の困難軸方向を磁界検出方向とするため、外部から印加された磁界が取り去られた後も軟磁性薄膜中に残留磁化が少なく、従って、正確な磁界の計測が可能になる。
【００３８】
【発明の効果】
以上の説明の通り、本発明によれば次のような効果が得られる。
【００３９】
巨大磁気抵抗薄膜の有する電気抵抗値の温度変化等、磁界印加による電気抵抗値変化以外は、すべてブリッジ回路の中で相殺されてブリッジ出力としては出ないため、従来技術では問題であった巨大磁気抵抗薄膜の温度等による電気抵抗値変化が除外されて、純粋に磁界の印加による変化分が検出可能である。
【００４０】
ブリッジ回路の持つ微小な電気抵抗値変化の検出機能が利用出来るため、極めて小さな変化に対応する、高い分解能での磁界検出が可能である。
【００４１】
２つの巨大磁気抵抗薄膜の両側に配置された材料の違いによって生じる微小な抵抗値の違いを避けるため、２つの巨大磁気抵抗薄膜の両側に配置する材料を同一とすることにより、磁界以外の要因による電気抵抗値変化は、更に厳密に相殺される。
【００４２】
巨大磁気抵抗薄膜の両側に配置する軟磁性薄膜の長さを減らし、その代わりに幅を広く取ることにより、磁界センサの感度を低下させることなく、磁界センサ全体としての小型化が可能である。
【００４３】
巨大磁気抵抗薄膜の両側に配置する軟磁性薄膜として、残留磁化が少ない一軸異方性を持った材料を適用することにより、検出すべき磁界を除いた後の残留磁化による磁界検出精度の低下を防止することができる。
【００４４】
本発明の薄膜磁界センサは、構造が単純で小型化が可能であり、また優れた磁界感度を有するので、次世代の高性能磁界センサーとして、その工業的意義は極めて大きい。
【図面の簡単な説明】
【図１】従来技術による薄膜磁界センサ
【図２】同上の磁界印加による抵抗値の変化
【図３】同上の抵抗値の温度特性
【図４】本発明の第１の実施例
【図５】本発明の第１の実施例の素子５の磁界と抵抗変化との関係
【図６】本発明の第１の実施例の素子５および素子１０の抵抗値温度特性
【図７】本発明の第１の実施例の素子１０の磁界と抵抗変化との関係
【図８】同上の電気的等価回路
【図９】本発明の第２の実施例の１
【図１０】本発明の第２の実施例の２
【図１１】本発明の第３の実施例
【図１２】本発明の第４の実施例
【図１３】本発明の第５の実施例
【符号の説明】
１：第１の軟磁性薄膜
２：第１の巨大磁気抵抗薄膜
３：第１の軟磁性薄膜に接続される電気端子の１つ
４：第１の軟磁性薄膜に接続される他の電気端子
５：上記１〜４を含めた素子
６：第１の導体膜
７：第２の巨大磁気抵抗薄膜
８：第１の導体膜に接続される電気端子の１つ
９：第１の導体膜に接続される他の電気端子
１０：上記６〜９を含めた素子
１１：第１の抵抗器
１２：第１の抵抗器に接続される電気端子の１つ
１３：第１の抵抗器に接続される他の電気端子
１４：第２の抵抗器
１５：第２の抵抗器に接続される電気端子の１つ
１６：第２の抵抗器に接続される他の電気端子
１７：駆動電圧を与えられる電気端子の１つ
１８：駆動電圧を与えられる他の電気端子
１９：ブリッジ出力の電気端子の１つ
２０：ブリッジ出力の他の電気端子
２１：第２の軟磁性薄膜
２２：第３の巨大磁気抵抗薄膜
２３：第２の軟磁性薄膜に接続される電気端子の１つ
２４：第２の軟磁性薄膜に接続される他の電気端子
２５：上記２１〜２４を含めた素子
２６：第２の導体膜
２７：第４の巨大磁気抵抗薄膜
２８：第２の導体膜に接続される電気端子の１つ
２９：第２の導体膜に接続される他の電気端子
３０：上記２６〜２９を含めた素子
３１：第３の軟磁性薄膜
３２：第５の巨大磁気抵抗膜
３３：第３の軟磁性薄膜に接続される電気端子の１つ
３４：第３の軟磁性薄膜に接続される他の電気端子
３５：上記３１〜３４を含めた素子[0001]
[Industrial application fields]
  The present invention relates to a thin film magnetic field sensor for measuring a magnetic field in space, and relates to a thin film magnetic field sensor for accurately measuring a magnetic field using a giant magnetoresistive thin film, for example, a nanogranular giant magnetoresistive thin film.
[0002]
[Prior art]
  FIG. 1 shows a magnetic field sensor described in JP-A-11-87804 and JP-A-11-274599. In the figure, a portion written as a giant magnetoresistive thin film is a metal-insulator nanogranular giant magnetoresistive thin film that exhibits an electric resistance change of about 10% when a magnetic field of 10 kOe is applied. As in this example, in the case of a giant magnetoresistive thin film, the variation range of the electrical resistance value is larger than that of a general magnetoresistive material, but the applied magnetic field for causing the electrical resistance change as described above. When only a giant magnetoresistive thin film is used alone, a change in electrical resistance value with a small magnetic field that is generally used as a magnetic field sensor cannot be expected. The configuration of FIG. 1 supplements this. In other words, the soft magnetic thin film plays the role of collecting the magnetic flux around it, and by selecting the appropriate soft magnetic thin film dimensions, in principle, regardless of the magnitude of the magnetic field around the soft magnetic thin film, It is possible to apply a very high magnetic flux density to the thin film portion within the saturation magnetic flux density of the soft magnetic thin film. Further, from the viewpoint of electrical resistance, the electrical resistance value between the soft magnetic thin films is the sum of the electrical resistance values of the soft magnetic thin film portion and the giant magnetoresistive thin film portion. Since the value of the electrical resistivity of the thin film is 100 times larger than that of the soft magnetic thin film, the electrical resistance value between the soft magnetic thin films is substantially equal to the value of the giant magnetoresistive thin film portion. That is, the electrical resistance value of the giant magnetoresistive thin film directly appears in the electrical resistance value between the soft magnetic thin films. FIG. 2 shows an example of such an electrical resistance change in the configuration of FIG. 1, and an electrical resistance value change of about 6% is realized in a small magnetic field of several Oe.
[0003]
[Problems to be solved by the invention]
  However, when the magnetic field sensor for measuring the absolute value of the applied magnetic field based on the measured electric resistance value of the giant magnetoresistive thin film, which is the object of the present invention, is realized, the configuration of FIG. It turns out that there is a problem. That is a problem of change in electrical resistance value due to the temperature of the giant magnetoresistive thin film. As described above, in the case of the configuration of FIG. 1, there is room for selection for the magnitude of the magnetic field to be detected. However, no matter how much the sensitivity is increased, it is a choice for the moving magnetic field, and it is not possible in principle to obtain a change width larger than the electric resistance change of the giant magnetoresistive thin film. Actually, the electrical resistance change width in the case of the configuration of FIG. 1 is about 6% after further compression including other factors. If there is a change due to the temperature of the giant magnetoresistive thin film with respect to this 6% change in electric resistance value, only the change in the electric resistance value becomes an uncertain factor in estimating the applied magnetic field. FIG. 3 shows an example of temperature characteristics. As is clear from this figure, it depends on the temperature of the giant magnetoresistive thin film.ElectricalThe change in resistance value is larger than the change in resistance due to application of a magnetic field, and the configuration shown in FIG. 1 is difficult to use as a magnetic field sensor for measuring the absolute value of a magnetic field.
[Means for Solving the Problems]
[0004]
  The features of the present invention are as follows. The first invention includes a soft magnetic thin film 1 that is divided into two by a gap having a predetermined gap length, has a predetermined film thickness and a predetermined width in contact with the gap, and a giant magnetoresistive thin film 2 formed so as to fill the gap. Terminal 3 and terminal 4 electrically connected to each of the soft magnetic thin film 1 divided into two, and a film that is divided into two by a gap having a gap length substantially equal to the gap length and substantially equal to the film thickness Electrically connected to each of the conductor film 6 having a thickness and a width substantially equal to the width in contact with the gap, the giant magnetoresistive thin film 7 formed so as to fill the gap, and the conductor film 6 divided in two Thin film magnetic field sensor characterized in that terminal 3 and terminal 4 and terminal 8 and terminal 9 respectively form two arms of a bridge circuit.ProvideTo do.
[0005]
  The second invention comprises a soft magnetic thin film 1 that is divided into two by a gap having a predetermined gap length, has a predetermined film thickness and a predetermined width in contact with the gap, and a giant magnetoresistive thin film 2 formed so as to fill the gap, Terminal 3 and terminal 4 electrically connected to each of the soft magnetic thin film 1 divided into two, and a film that is divided into two by a gap having a gap length substantially equal to the gap length and substantially equal to the film thickness The conductor film 6 having a thickness and a width substantially equal to the width in contact with the gap, the giant magnetoresistive thin film 7 formed so as to fill the gap, and the conductor film 6 divided into two are electrically connected to each other. Terminal 8 and terminal 9 are divided into two by a gap having a gap length substantially equal to the gap length, and soft magnetic having a film thickness substantially equal to the film thickness and a width substantially equal to the width in contact with the gap Thin film 21, filling the gap The giant magnetoresistive thin film 22 formed as described above, the terminal 23 and the terminal 24 electrically connected to each of the two divided soft magnetic thin films 21, and the gap having a gap length substantially equal to the gap length. A conductor film 26 having a film thickness substantially equal to the film thickness and a width substantially equal to the width in contact with the gap, a giant magnetoresistive thin film 27 formed so as to fill the gap, and The conductor film 26 includes a terminal 28 and a terminal 29 electrically connected to each of the conductor films 26. The terminal 3 and the terminal 4, the terminal 8 and the terminal 9, the terminal 23 and the terminal 24, and the terminal 28 and the terminal 29 are respectively 4 Thin film magnetic field sensor characterized by forming two armsProvideTo do.
[0006]
  The third invention comprises a soft magnetic thin film 1 having a predetermined film thickness and a predetermined width in contact with the air gap, a giant magnetoresistive thin film 2 formed so as to fill the air gap. Terminal 3 and terminal 4 electrically connected to each of the soft magnetic thin film 1 divided into two, and a film that is divided into two by a gap having a gap length substantially equal to the gap length and substantially equal to the film thickness Each of the soft magnetic thin film 31 having a thickness and a width substantially equal to the width in contact with the air gap, the giant magnetoresistive thin film 32 formed so as to fill the air gap, and the soft magnetic thin film 31 divided into two is electrically connected Terminal 3 and terminal 4, terminal 33 and terminal 34 form two arms of the bridge circuit, respectively, and the area on the plane of the soft magnetic thin film 31 is soft. Magnetic thin Thin film magnetic field sensor, characterized in that in comparison to the area of the first plane is less than 1/10ProvideTo do.
[0007]
  According to a fourth aspect of the present invention, at least a part of the width dimension of the soft magnetic thin film 1 measured along a line parallel to the line in contact with the air gap is larger than the width of the line in which the soft magnetic thin film 1 is in contact with the air gap. The thin film magnetic field sensor according to any one of the first to third inventionsProvideTo do.
[0008]
  According to a fifth aspect of the present invention, the magnetic properties of the soft magnetic thin film 1 are uniaxial anisotropy, and the direction of the easy axis of magnetization is substantially parallel to a line in contact with the air gap. The thin film magnetic field sensor according to any one of the invention to the third inventionProvideTo do.
[0009]
[Action]
  The operation of the present invention is as follows.
  The configuration of the first invention is a magnetic field sensor with high accuracy by excluding changes due to temperature, humidity and temporal causes from the change in electrical resistance value of the giant magnetoresistive thin film, and extracting only the change due to the magnetic field. Is realized. In other words, a giant magnetoresistive thin film and a bridge consisting of two elements with the same structurecircuitOne of the elements increases the sensitivity to the magnetic field by placing the soft magnetic thin film on both sides of the giant magnetoresistive thin film, and the other element substantially increases the sensitivity to the magnetic field by using the giant magnetoresistive thin film as it is. Is zero. bridgecircuitOutput voltage is proportional to the difference between the electrical resistance values of these elements. As a result, fluctuation factors such as temperature change and other changes in humidity, time, etc. of the giant magnetoresistive thin film are excluded from the output voltage. Only the change in electrical resistance value due to the magnetic field appears in the output. As a result, the absolute value of the magnetic field can be detected with high accuracy, and at the same time, an extremely small magnetic field can be detected.
[0010]
  The configuration of the second invention realizes a thin film magnetic field sensor with higher accuracy and higher magnetic field sensitivity. That is, by constructing a bridge circuit using two elements each having a soft magnetic thin film disposed on both sides of a giant magnetoresistive thin film and two elements having conductor films disposed on both sides of the giant magnetoresistive thin film, the bridge output voltage is Further, it is possible to further increase the size by twice as compared with the configuration of the first invention, and it is possible to realize a thin film magnetic field sensor with higher accuracy and higher magnetic field sensitivity.
[0011]
  The configuration of the third invention further enhances the accuracy of the thin film magnetic field sensor from the viewpoint of the material to be used. In other words, even if the material and structure of the giant magnetoresistive thin film portion in the elements constituting the bridge are exactly the same, but the material sandwiching the giant magnetoresistive thin film is different, a minute electrical resistance is generated due to the contact potential difference or thermoelectromotive force. There may be a difference in resistance value. According to the configuration of the third invention, including these problems, the change in the electric resistance value of the giant magnetoresistive thin film due to factors other than the resistance change due to the application of the magnetic field of the two structures can be canceled in a strict sense. Thus, a highly accurate thin film magnetic field sensor can be realized.
[0012]
  The configuration of the fourth invention realizes a smaller and more accurate thin film magnetic field sensor from the viewpoint of structure. In order to increase the sensitivity as a magnetic field sensor and to reduce the size of the magnetic sensor, the soft magnetic thin film is arranged on both sides of the giant magnetoresistive thin film, and the soft magnetic thin film has a constant effective area and is soft. It is necessary to reduce the size of the magnetic thin film portion. According to the configuration of the fourth aspect of the invention, it is possible to realize a magnetic field sensor having high sensitivity and smaller in shape.
[0013]
  The configuration of the fifth invention further increases the accuracy of the thin film magnetic field sensor from the aspect of residual magnetization. In other words, if the magnetization remains in the soft magnetic thin film after the measurement of the applied magnetic field is completed and the external magnetic field is removed, this residual magnetization is applied to the giant magnetoresistive thin film. As a result, the detection accuracy of the magnetic field is lowered. Therefore, in the configuration of the fifth aspect of the invention, the soft magnetic thin film is magnetized in the direction orthogonal to the detection magnetic field of the giant magnetoresistive thin film, thereby reducing the residual magnetization in the soft magnetic thin film and measuring the magnetic field with higher accuracy. be able to.
[0014]
【Example】
  Hereinafter, various embodiments of the present invention will be described with reference to the drawings. In each figure, the same elements are denoted by the same reference numerals to avoid duplication of explanation.
[0015]
  [Example 1]
  FIG. 4 shows a first embodiment of the present invention. In this figure and the subsequent figures, for the sake of understanding, the giant magnetoresistive thin film portion is distinguished by dotted marks, the soft magnetic thin film portion is slanted, and the conductor thin film portion is whitened. Reference numeral 5 denotes an element including the soft magnetic thin film 1, the giant magnetoresistive thin film 2, and the electrical terminals 3 and 4, and has the same configuration as that shown in FIG. The description of the action of element 5 is in the textParagraphSince it has been described in 0002, only the specific contents of the present invention are described here, avoiding duplication. A soft magnetic thin film 1 is a permalloy having a high saturation magnetic flux density of 15 kG or more and a low coercive force of 0.5 Oe or less. Table 1 shows specific material names and typical characteristics of the soft magnetic thin film 1 including other materials.
[0016]
[Table 1]
Figure 0004023997
[0017]
  The thickness of the soft magnetic thin film 1 is t = 1 μm. In the soft magnetic thin film 1, a void indicated by a void length g is formed. The dimension of the gap length g is g = 1 μm. The dimension of the width w of the soft magnetic thin film 1 in contact with the gap is w = 100 μm. A giant magnetoresistive thin film 2 is formed so as to fill the gap of the soft magnetic thin film 1. The material of the giant magnetoresistive thin film 2 is Co39Y14O47It is. Including this material, the possible material names for the giant magnetoresistive thin film 2 and their representative characteristics are shown in Table 2.
[0018]
[Table 2]
Figure 0004023997
[0019]
  Here, the thickness t of the soft magnetic thin film 1, the gap length g, and the width w of the soft magnetic thin film 1 in contact with the gap satisfy the required characteristics from both magnetic and electrical conditions. However, the feature of the present invention is to obtain the desired performance over a wide range. That is, the selection range of dimensions is very wide. As a magnetic condition, when the gap length g is too wide, for example, when it is more than several times the thickness t of the soft magnetic thin film, the soft magnetic thin film 1 collects the surrounding magnetic flux and sufficiently supplies the magnetic flux to the gap portion. I can't concentrate. On the other hand, the thickness t of the soft magnetic thin film exhibits the function of the present invention no matter how thick it is, but the deposition capacity per unit time of the apparatus for forming the soft magnetic thin film, or the soft magnetic thin film is the substrate. The thickness limit is determined by practical constraints such as peeling of the soft magnetic thin film from the substrate due to the stress when the film is formed. Conversely, when the thickness t of the soft magnetic thin film is 10 nm or less, the magnetic properties of the soft magnetic thin film deteriorate, so that 10 nm is substantially the lower limit of the thickness. As an electrical condition, the width w of the soft magnetic thin film 1 is considered to be a value that is easy for the peripheral circuit to handle as the magnetic sensor and the absolute value of the electrical resistance, for example, in the range of several tens of kΩ to several hundreds of MΩ. Must be set. The absolute value of the electrical resistance is proportional to the electrical resistivity and the gap length g of the giant magnetoresistive thin film, and inversely proportional to the width w of the soft magnetic thin film and the thickness t of the soft magnetic thin film. The specific width g of the soft magnetic thin film is realizable in a wide range from a maximum of several mm to a minimum of several μm.
[0020]
  Electrical terminals 3 and 4 made of Cu are connected to the soft magnetic thin films 1 on both sides that are divided into two with a gap in between. Since the material of the electrical terminal portion does not have a large magnetic effect, it can be determined with a focus on electrical continuity, and the material of the soft magnetic thin film can be used in common. It is also possible to form a Cu film on the surface only in a portion that is used for connection to the outside. Reference numeral 5 denotes an element including the soft magnetic thin film 1, the giant magnetoresistive thin film 2, and the electrical terminals 3 and 4. The electrical resistance value between the electrical terminals 3 and 4 is represented as Ra. FIG. 5 shows an example of the relationship between the applied magnetic field of the element 5 and the change in the electric resistance value with the length dimension L of the soft magnetic thin film 1 as a parameter. By increasing the length dimension L, FIG. It can be seen that it can be moved in a magnetic field. FIG. 6 shows a change in resistance value due to the temperature of the element 5. The relationship between the applied magnetic field and the electric resistance value in FIG. 5 changes substantially linearly up to a certain magnitude of magnetic field if the absolute value of the applied magnetic field is taken. Further, the change in temperature and electrical resistance value in FIG. 6 is regarded as a linear relationship near room temperature. Therefore, the resistance value when the applied magnetic field is zero and the temperature is 22 ° C. is R0Assuming that the absolute value of the applied magnetic field is H and the temperature is T, the resistance value Ra can be expressed as Equation 1.
[0021]
  Ra = R0(1 + rMH + rT(T-25)) (1)
  Where rMIs the differential coefficient of the change in electric resistance value due to the applied magnetic field,TIs the temperature coefficient of the electrical resistance value. Table 3 shows r for each length dimension L of the soft magnetic thin film.MAnd the range of the magnetic field H in which Equation 1 holds, and rTThe value of is shown.
[0022]
[Table 3]
Figure 0004023997
[0023]
  Reference numeral 6 denotes a conductor film having substantially the same thickness t ′ as that of the soft magnetic thin film 1. The material of the conductor film 6 is Cu. Cu material exhibits very weak diamagnetism, but is almost magnetically considered transparent. The conductor film 6 is formed with a gap length g ′ having a size substantially equal to the gap length g of the soft magnetic thin film 1. The width w ′ of the conductor film 6 in contact with the gap is substantially the same as the width w of the soft magnetic thin film 1 in contact with the gap. The length dimension corresponding to L of the element 5 is arbitrary. A giant magnetoresistive thin film 7 is formed so as to fill the gap of the conductor film 6. The material of the giant magnetoresistive thin film 7 is the same as that of the giant magnetoresistive thin film 2. Electrical terminals 8 and 9 are connected to the conductor films 6 on both sides that are divided into two with the gap in between. Reference numeral 10 denotes an element including the conductor film 6, the giant magnetoresistive thin film 7, and the electrical terminals 8 and 9. The electrical resistance between the electrical terminals 8 and 9 is represented as Rb.
[0024]
  For the element 10, since the conductor film 6 has no magnetic action, the magnetic flux density applied to the giant magnetoresistive thin film 7 is the magnetic flux density of the environment where the giant magnetoresistive thin film 7 is placed. FIG. 7 shows the change in Rb due to the applied magnetic field, and the change in the electric resistance value due to the applied magnetic field is substantially regarded as zero. On the other hand, as a change with respect to temperature, the same temperature coefficient as the temperature coefficient shown in FIG. 6 is shown. Therefore, in the case of the element 10 corresponding to Equation 1,ElectricalAn equation for the resistance value Rb is shown in Equation 2.
  Rb = R 0 (1 + r T (T-25)) (2)
[0025]
  11ElectricalThis is a first resistor having a resistance value Rc, and electrical terminals 12 and 13 are connected to the first resistor 11. 14 isElectricalThis is a second resistor having a resistance value Rd. Electrical terminals 15 and 16 are connected to the second resistor 14. About the 1st resistor and the 2nd resistor, the resistance value and its temperature coefficient between them are precisely matched. Similar to Equations 1 and 2,ElectricalLet the temperature coefficient of resistance be rTIf ′, then Equations 3 and 4 are obtained.
  Rc = R 0 (1 + r T '(T-25)) (3)
  Rd = R 0 (1 + r T '(T-25)) (4)
[0026]
  The terminals 4, 8 and 20, the terminals 3, 12 and 17, the terminals 9, 16 and 18, and the terminals 13, 15 and 19 are electrically connected. FIG. 8 shows the configuration of FIG. 4 as an electrical equivalent circuit, and forms one bridge circuit as a whole. Element 5 and element 10 form two arms of the bridge circuit. A drive voltage is applied between the terminals 17 and 18, and an output voltage of the bridge appears between the terminals 19 and 20. In the circuit of FIG.0When voltage is applied, voltage V appearing between terminals 19 and 202Is represented by Equation 5.
  V 2 = (RaRd-RbRc) V 0 /((Ra+Rb).(Rc+Rd)) (5)
[0027]
  By substituting Equations 1, 2, 3, and 4 for Ra, Rb, Rc, and Rd in Equation 5, respectively, and omitting the secondary minute amount, V2All the terms related to the temperature are canceled out to obtain Equation 6.
  V 2 = R T HV 0 / 4 (6)
[0028]
  Where V0, RT, R0Is a constant that can be determined in advance, V2If the measured value is obtained, the target magnetic field can be determined as shown in Equation 7.
  H = 4V 2 / (V 0 r T (7)
[0029]
  Bridge circuit output V2As V0The level at which stable detection is possible is determined by the stability of the amplifier of the bridge circuit output voltage, etc.2/ V0= 1x10-5Is easily realizable. Therefore, in Equation 7, V2/ V0= 1x10-5And r in Table 3TBy substituting the value of, the magnetic field resolution possible with the present invention is obtained. The results are shown in Table 4.
[0030]
[Table 4]
Figure 0004023997
[0031]
  The resolution in Table 4 is comparable to that of a prior art FlexGate sensor. This FluxGate sensor uses the saturation characteristic of a magnetic material, and is quite complicated and large in size as a sensor structure and a peripheral circuit configuration. The configuration of the present invention is extremely simple and small and light compared to these magnetic field sensors, and the utility of the present invention is extremely high.
[0032]
  [Example 2-1]
  FIG. 9 shows one of the second embodiments of the present invention. In the figure, each of the elements 25 is the same as the element 5 described in FIG. In the entire circuit, the element 25 is replaced with the first resistor, and the element 30 is replaced with the second resistor. If FIG. 9 is expressed as an equivalent circuit, the circuit is the same as the circuit shown in FIG. 8 as a whole, but in the case of FIG. 9, Rd = Ra and Rc = Rb are established. Similar to Equation 6, if Equations 1 and 2 are substituted into Equation 5, Equation 8 is obtained.
  V 2 = R T HV 0 / 2 (8)
[0033]
  Here, the value of Expression 8 is twice that of Expression 6. Therefore, according to the configuration of FIG. 9, it is possible to estimate the magnitude of the magnetic field more accurately than the configuration of FIG. 4, and the resolution of the detectable magnetic field is further increased.DoubleCan be increased up to.
[0034]
  [Example 2-2]
  FIG. 10 shows another one of the second embodiment of the present invention. In FIG. 10, the element 5 and the element 25 are arranged in parallel, and the element 10 and the element 30 are arranged between them, so that the effective use of the occupied area as a whole is planned. Further, the terminals 4 and 8, the terminals 24 and 28, the terminals 3 and 9, and the terminals 23 and 29 are common to each other, and the connection between these terminals is omitted to simplify the structure. It is measuring. As for connection terminals 17, 18, 19, and 20 to the external circuit, terminals 3 and 9, terminals 23 and 29, terminals 4 and 8, and terminals 24 and 28 are not directly connected. 25 and is electrically connected, and has an electrical function similar to that shown in FIG. In the case of FIG. 10, the angle at which the giant magnetoresistive thin film is placed is orthogonal between the element 5 and the element 10, and the element 25 and the element 30. The element 10 and the element 30 have almost zero sensitivity to the magnetic field as shown in FIG. 7. However, by arranging the elements 10 and 30 as shown in FIG. In addition, the change in electrical resistance of the element 10 and the element 30 can be made zero.
[0035]
  [Example 3]
  FIG. 11 shows a third embodiment of the present invention. The difference between this embodiment and the first embodiment is that the same material as that of the soft magnetic thin film 1 is used as the conductor film 6 shown in FIG. In FIG. 4, it is necessary to make the changes of the electric resistances of the elements 5 and 10 other than the change due to the magnetic field as equal as possible and cancel each other in the bridge circuit. For this purpose, first, the material and structure of the giant magnetoresistive thin film itself should be made common, but even if the giant magnetoresistive thin film itself is exactly the same, depending on the material in contact with it, a fine electrical resistance value may be obtained. There may be a difference. The cause is a contact potential difference or a thermoelectromotive force. In Example 3 shown in FIG. 11, this material is avoided by making the material brought into contact with the giant magnetoresistive thin film a soft magnetic thin film common to the element 5 and the element 35. However, when the size of the soft magnetic thin film 31 of the element 35 is increased, the magnetic flux density inevitably applied to the giant magnetoresistive thin film 32 also increases, and the sensitivity of the magnetic field sensor as the difference in resistance between the elements 5 and 32 is reduced. End up. In the third embodiment, this problem is avoided by setting the area of the soft magnetic thin film 31 of the element 35 to 1/10 or less of the area of the soft magnetic thin film 1 of the element 5. According to this configuration, it is possible to secure an output voltage of at least 90% or more with respect to the bridge output voltage when the conductor portion of the element 35 is a non-magnetic material, and to change the resistance due to factors other than the application of the magnetic field. And the element 35 can be exactly canceled, and a highly accurate thin film magnetic field sensor can be realized.
[0036]
  [Example 4]
  FIG. 12 shows a fourth embodiment of the present invention. In Example 1, it was described that the sensitivity of the moving magnetic field can be increased by increasing the L dimension of the soft magnetic thin film for the element 5. The function of the soft magnetic thin film 1 is to collect peripheral magnetic flux and concentrate it on the giant magnetoresistive thin film portion, but the function of collecting peripheral magnetic flux is almost proportional to the area of the soft magnetic thin film. Therefore, in the case of the configuration shown in FIG. 4, in order to provide sensitivity with a small magnetic field, it is necessary to increase the L dimension, and the overall dimension of the magnetic field sensor is inevitably increased. . According to the configuration of FIG. 12, the soft magnetic thin film is provided with a portion having a width of wx that is larger than the width w of contact with the giant magnetoresistive thin film, so that the occupied area of the soft magnetic thin film can be effectively used, and the overall size can be reduced. In addition, a magnetic sensor with high magnetic field sensitivity can be realized.
[0037]
  [Example 5]
  FIG. 13 shows a fifth embodiment of the present invention. In a soft magnetic thin film, even if an external magnetic field is applied, magnetization hardly remains after the external magnetic field is removed, but magnetization may remain within the coercive force Hc range. Since this residual magnetization is a direct error of the magnetic field to be detected, a material having as little residual magnetization as possible is desirable. As shown in Table 1, Co77Fe5Si9B 9 The material has a low Hc of about 1/6 compared with permalloy, and this value is obtained when excited in the hard axis direction. In general, since the magnetization process in the hard axis direction of a magnetic material having uniaxial anisotropy is due to magnetization rotation, no hysteresis occurs and Hc becomes almost zero. Therefore, no residual magnetization occurs in the hard axis direction. According to the fifth configuration of the present invention, since the hard axis direction of the material having uniaxial anisotropy is set as the magnetic field detection direction, the residual magnetization in the soft magnetic thin film is removed even after the externally applied magnetic field is removed. Therefore, accurate magnetic field measurement is possible.
[0038]
【The invention's effect】
  As described above, according to the present invention, the following effects can be obtained.
[0039]
  Except for changes in electrical resistance due to application of a magnetic field, such as changes in temperature of the electrical resistance of a giant magnetoresistive thin film, they are canceled out in the bridge circuit and do not appear as bridge output. The change in the electric resistance value due to the temperature of the resistive thin film is excluded, and the change due to the application of the magnetic field can be detected purely.
[0040]
  Since the detection function of a minute change in electrical resistance value of the bridge circuit can be used, it is possible to detect a magnetic field with high resolution corresponding to an extremely small change.
[0041]
  In order to avoid the small difference in resistance value caused by the difference in the materials placed on both sides of the two giant magnetoresistive thin films, the same material is placed on both sides of the two giant magnetoresistive thin films, thereby causing factors other than the magnetic field. The change in the electric resistance value due to is canceled more strictly.
[0042]
  By reducing the length of the soft magnetic thin film disposed on both sides of the giant magnetoresistive thin film and taking a wider width instead, it is possible to reduce the size of the magnetic field sensor as a whole without reducing the sensitivity of the magnetic field sensor.
[0043]
  The soft magnetic thin film placed on both sides of the giant magnetoresistive thin film can reduce the magnetic field detection accuracy due to the residual magnetization after removing the magnetic field to be detected by applying a material with little residual magnetization and uniaxial anisotropy. Can be prevented.
[0044]
  The thin film magnetic field sensor of the present invention has a simple structure, can be miniaturized, and has excellent magnetic field sensitivity. Therefore, the industrial significance of the thin film magnetic field sensor is extremely large as a next-generation high-performance magnetic field sensor.
[Brief description of the drawings]
FIG. 1 shows a conventional thin film magnetic field sensor.
[Fig. 2] Change in resistance due to application of magnetic field
[Fig. 3] Temperature characteristics of resistance values as above
FIG. 4 shows a first embodiment of the present invention.
FIG. 5 shows the relationship between the magnetic field and resistance change of the element 5 of the first embodiment of the present invention.
FIG. 6 shows resistance-temperature characteristics of the element 5 and the element 10 according to the first embodiment of the present invention.
FIG. 7 shows the relationship between the magnetic field and resistance change of the element 10 of the first embodiment of the present invention.
FIG. 8 is an electrical equivalent circuit of the above.
FIG. 9 shows a second embodiment of the present invention.
FIG. 10 shows the second embodiment of the present invention.
FIG. 11 shows a third embodiment of the present invention.
FIG. 12 shows a fourth embodiment of the present invention.
FIG. 13 shows a fifth embodiment of the present invention.
[Explanation of symbols]
1: First soft magnetic thin film
2: First giant magnetoresistive thin film
3: One of the electrical terminals connected to the first soft magnetic thin film
4: Other electrical terminals connected to the first soft magnetic thin film
5: Element including 1 to 4 above
6: First conductor film
7: Second giant magnetoresistive thin film
8: One of the electrical terminals connected to the first conductor film
9: Other electrical terminal connected to the first conductor film
10: Element including the above 6 to 9
11: First resistor
12: One of the electrical terminals connected to the first resistor
13: Other electrical terminal connected to the first resistor
14: Second resistor
15: One of the electrical terminals connected to the second resistor
16: Other electrical terminal connected to the second resistor
17: One of the electrical terminals to which the drive voltage is applied
18: Other electrical terminal to which drive voltage is applied
19: One of the electrical terminals for bridge output
20: Other electrical terminal for bridge output
21: Second soft magnetic thin film
22: Third giant magnetoresistive thin film
23: One of the electrical terminals connected to the second soft magnetic thin film
24: Other electrical terminal connected to the second soft magnetic thin film
25: Device including 21 to 24 above
26: Second conductor film
27: Fourth giant magnetoresistive thin film
28: One of the electrical terminals connected to the second conductor film
29: Other electrical terminal connected to the second conductor film
30: Device including the above 26-29
31: Third soft magnetic thin film
32: Fifth giant magnetoresistive film
33: One of the electrical terminals connected to the third soft magnetic thin film
34: Other electrical terminal connected to the third soft magnetic thin film
35: Element including the above 31 to 34

Claims (5)

所定の空隙長を持つ空隙によって２分割され、所定の膜厚および空隙に接する所定の幅を持つ軟磁性薄膜１、その空隙を埋めるように形成された巨大磁気抵抗薄膜２、２分割された軟磁性薄膜１の各々に電気的に接続された端子３および端子４、前記空隙長と実質的に等しい空隙長を持つ空隙によって２分割され、前記膜厚と実質的に等しい膜厚、および前記空隙に接する幅と実質的に等しい幅を持つ導体膜６、その空隙を埋めるように形成された巨大磁気抵抗薄膜７、および２分割された導体膜６の各々に電気的に接続された端子８および端子９からなり、端子３および端子４と端子８および端子９は、各々ブリッジ回路の２つのアームを形成することを特徴とする薄膜磁界センサ。  A soft magnetic thin film 1 having a predetermined film thickness and a predetermined width in contact with the air gap, a giant magnetoresistive thin film 2 formed so as to fill the air gap, and divided into two by a gap having a predetermined air gap length. Terminals 3 and 4 electrically connected to each of the magnetic thin films 1, divided into two by a gap having a gap length substantially equal to the gap length, and a film thickness substantially equal to the film thickness, and the gap A conductor film 6 having a width substantially equal to the width in contact with each other, a giant magnetoresistive thin film 7 formed so as to fill the gap, and a terminal 8 electrically connected to each of the conductor film 6 divided into two and A thin film magnetic field sensor comprising terminals 9, wherein terminal 3, terminal 4, terminal 8, and terminal 9 each form two arms of a bridge circuit. 所定の空隙長を持つ空隙によって２分割され、所定の膜厚および空隙に接する所定の幅を持つ軟磁性薄膜１、その空隙を埋めるように形成された巨大磁気抵抗薄膜２、２分割された軟磁性薄膜１の各々に電気的に接続された端子３および端子４、前記空隙長と実質的に等しい空隙長を持つ空隙によって２分割され、前記膜厚と実質的に等しい膜厚および前記空隙に接する幅と実質的に等しい幅を持つ導体膜６、その空隙を埋めるように形成された巨大磁気抵抗薄膜７、２分割された導体膜６の各々に電気的に接続された端子８および端子９、前記空隙長と実質的に等しい空隙長を持つ空隙によって２分割され、前記膜厚と実質的に等しい膜厚および前記空隙に接する幅と実質的に等しい幅を持つ軟磁性薄膜２１、その空隙を埋めるように形成された巨大磁気抵抗薄膜２２、２分割された軟磁性薄膜２１の各々に電気的に接続された端子２３および端子２４、前記空隙長と実質的に等しい空隙長を持つ空隙によって２分割され、前記膜厚と実質的に等しい膜厚および前記空隙に接する幅と実質的に等しい幅を持つ導体膜２６、その空隙を埋めるように形成された巨大磁気抵抗薄膜２７、および２分割された導体膜２６の各々に電気的に接続された端子２８および端子２９からなり、端子３および端子４、端子８および端子９、端子２３および端子２４、端子２８および端子２９は、各々ブリッジ回路の４つのアームを形成することを特徴とする薄膜磁界センサ。  A soft magnetic thin film 1 having a predetermined film thickness and a predetermined width in contact with the air gap, a giant magnetoresistive thin film 2 formed so as to fill the air gap, and divided into two by a gap having a predetermined air gap length. The terminals 3 and 4 electrically connected to each of the magnetic thin films 1 are divided into two by a gap having a gap length substantially equal to the gap length. A conductor film 6 having a width substantially equal to the contact width, a giant magnetoresistive thin film 7 formed so as to fill the gap, and a terminal 8 and a terminal 9 electrically connected to each of the divided conductor films 6 The soft magnetic thin film 21 is divided into two by a gap having a gap length substantially equal to the gap length, and has a thickness substantially equal to the film thickness and a width substantially equal to the width in contact with the gap, and the gap Formed to fill The giant magnetoresistive thin film 22, the terminal 23 and the terminal 24 electrically connected to each of the divided soft magnetic thin film 21, divided into two by a gap having a gap length substantially equal to the gap length, A conductor film 26 having a film thickness substantially equal to the film thickness and a width substantially equal to the width in contact with the gap, a giant magnetoresistive thin film 27 formed so as to fill the gap, and a conductor film 26 divided into two Terminal 28 and terminal 29, terminal 3 and terminal 4, terminal 8 and terminal 9, terminal 23 and terminal 24, and terminal 28 and terminal 29 are respectively connected to the four arms of the bridge circuit. A thin film magnetic field sensor characterized by being formed. 所定の空隙長を持つ空隙によって２分割され、所定の膜厚および空隙に接する所定の幅を持つ軟磁性薄膜１、その空隙を埋めるように形成された巨大磁気抵抗薄膜２、２分割された軟磁性薄膜１の各々に電気的に接続された端子３および端子４、前記空隙長と実質的に等しい空隙長を持つ空隙によって２分割され、前記膜厚と実質的に等しい膜厚、および前記空隙に接する幅と実質的に等しい幅を持つ軟磁性薄膜３１、その空隙を埋めるように形成された巨大磁気抵抗薄膜３２、および２分割された軟磁性薄膜３１の各々に電気的に接続された端子３３および端子３４からなり、端子３および端子４、端子３３および端子３４は、各々ブリッジ回路の２つのアームを形成し、且つまた軟磁性薄膜３１の平面上の面積は、軟磁性薄膜１の平面上の面積に比して１／１０以下であることを特徴とする薄膜磁界センサ。  A soft magnetic thin film 1 having a predetermined film thickness and a predetermined width in contact with the air gap, a giant magnetoresistive thin film 2 formed so as to fill the air gap, and divided into two by a gap having a predetermined air gap length. Terminals 3 and 4 electrically connected to each of the magnetic thin films 1, divided into two by a gap having a gap length substantially equal to the gap length, and a film thickness substantially equal to the film thickness, and the gap A soft magnetic thin film 31 having a width substantially equal to the width in contact with each other, a giant magnetoresistive thin film 32 formed so as to fill the gap, and a terminal electrically connected to each of the two divided soft magnetic thin films 31 33 and terminal 34, terminal 3 and terminal 4, terminal 33 and terminal 34 each form two arms of the bridge circuit, and the area on the plane of soft magnetic thin film 31 is the plane of soft magnetic thin film 1 Up Thin film magnetic field sensor, characterized in that in comparison with the area less than 1/10. 空隙に接する線と並行な線に沿って測った軟磁性薄膜１の幅寸法の少なくとも一部は、その軟磁性薄膜１が空隙に接する線の幅よりも大であることを特徴とする請求項１ないし請求項３のいずれか１項に記載の薄膜磁界センサ。  The width dimension of the soft magnetic thin film 1 measured along a line parallel to the line in contact with the gap is larger than the width of the line in which the soft magnetic thin film 1 is in contact with the gap. The thin film magnetic field sensor of any one of Claim 1 thru | or 3. 軟磁性薄膜１の磁気特性は一軸異方性であって、その磁化容易軸方向は、実質的に、空隙に接する線と並行な方向であることを特徴とする請求項１ないし請求項３のいずれか１項に記載の薄膜磁界センサ。  4. The magnetic property of the soft magnetic thin film 1 is uniaxial anisotropy, and the direction of the easy axis of magnetization is substantially parallel to a line in contact with the air gap. The thin film magnetic field sensor of any one of Claims.
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DE60139017T DE60139017D1 (en) 2000-10-26 2001-10-25 THIN FILM MAGNETIC SENSOR
AT01978911T ATE434192T1 (en) 2000-10-26 2001-10-25 THIN FILM MAGNETIC FIELD SENSOR
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CNB018032648A CN100403048C (en) 2000-10-26 2001-10-25 Thin-film magnetic field sensor
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CN104508501A (en) * 2012-05-11 2015-04-08 公立大学法人大阪市立大学 Power factor measurement device

Families Citing this family (7)

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JP4334914B2 (en) * 2003-05-28 2009-09-30 財団法人電気磁気材料研究所 Thin film magnetic sensor
JP4323220B2 (en) * 2003-05-28 2009-09-02 財団法人電気磁気材料研究所 Thin film magnetic sensor and manufacturing method thereof
JP2008209224A (en) * 2007-02-26 2008-09-11 Daido Steel Co Ltd Magnetic sensor
CN103558467B (en) * 2013-10-29 2015-08-26 中国南方电网有限责任公司超高压输电公司 A kind of computing method of capacitive apparatus parameter
CN104808158A (en) * 2015-05-07 2015-07-29 李川 Ferroxcube detector
CN107037381A (en) * 2015-12-29 2017-08-11 爱盛科技股份有限公司 Magnetic field sensing device and sensing method thereof
JP2018151332A (en) * 2017-03-14 2018-09-27 大同特殊鋼株式会社 Thin-film magnetic sensor

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* Cited by examiner, † Cited by third party
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JP3466470B2 (en) * 1998-03-18 2003-11-10 財団法人電気磁気材料研究所 Thin film magnetoresistive element
JP2000180207A (en) * 1998-12-16 2000-06-30 Yazaki Corp Magnetism sensor

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