JP2004179187A - Magnetoresistive element and magnetic memory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetoresistive effect element that has a little fluctuating a switching magnetic field and MR ratio, keeps the switching magnetic field at a small value even when the bit size is reduced, and is excellent in thermal stability. <P>SOLUTION: This magnetoresistive effect element has at least one tunnel barrier layer and a magnetic recording layer and a magnetization fixing layer provided on both sides of the barrier layer. The magnetic recording layer contains at least two amorphous magnetic layers and a nonmagnetic layer interposed between the magnetic layers. <P>COPYRIGHT: (C)2004,JPO

Description

【００６９】
【表２】

【００７０】
【表３】

【００７１】
【表４】

【００７２】
【表５】

【００７３】
【表６】

【００７４】
【表７】

【００７５】
【表８】

【００７６】
【表９】

【００７７】
【表１０】

【００７８】
【表１１】

【００７９】
【表１２】

【００８０】
【表１３】

【００８１】
【表１４】

【００８２】
【表１５】

【００８３】
【表１６】

【００８４】
【表１７】

【００８５】
【表１８】

【００８６】
【表１９】

【００８７】
【表２０】

【００８８】
【表２１】

【００８９】
【表２２】

【００９０】
【表２３】

【００９１】
【表２４】

【００９２】
以上のような磁気抵抗効果素子を磁気メモリ（ＭＲＡＭ）に適用する場合には、第１の方向に延在する第１の配線と、第１の配線の上方に設けられ、第１の方向と交差する方向に延在する第２の配線とを形成し、第１の配線と第２の配線との間に、少なくとも一層のトンネルバリア層と、前記トンネルバリア層を挟んで設けられた磁気記録層および磁化固着層とを有し、前記磁気記録層が少なくとも２層のアモルファス磁性層とその間に挿入された非磁性層を含むことを特徴とする磁気抵抗効果素子とを設ける。具体的なＭＲＡＭのアーキテクチャについては後に詳細に説明する。
【００９３】
【実施例】
（実施例１）
非磁性層の膜厚を変化させて強磁性層／非磁性層／強磁性層の積層構造を形成し、非磁性層を介した二層の強磁性層間の相互作用を調べた。
【００９４】
アモルファス磁性層／非磁性層／アモルファス磁性層として、
Ａ：（Ｃｏ_９０Ｆｅ_１０）_８０Ｂ_２０／Ｒｕ／（Ｃｏ_９０Ｆｅ_１０）_８０Ｂ_{２０ 、および}
Ｂ：（Ｃｏ_０．９５Ｆｅ_０．０５）_７５（Ｓｉ_０．５Ｂ_０．５）_２５／Ｒｕ／（Ｃｏ_０．９５Ｆｅ_０．０５）_７５（Ｓｉ_０．５Ｂ_０．５）_{２５
を形成した。}
比較のために、結晶質強磁性層／非磁性層／結晶質強磁性層として、
Ｃ：Ｃｏ_９０Ｆｅ_１０／Ｒｕ／Ｃｏ_９０Ｆｅ_１０
を形成した。
【００９５】
図１２に非磁性層（Ｒｕ）の膜厚と層間相互作用との関係を示す。図１２に示されるように、アモルファス磁性層を用いると層間相互作用が抑えられ、ＭＲＡＭの磁気記録層として好ましい特性を示した。また、アモルファス磁性層では、（Ｃｏ_９０Ｆｅ_１０）_８０Ｂ_２０よりも（Ｃｏ_０．９５Ｆｅ_０．０５）_７５（Ｓｉ_０．５Ｂ_０．５）_２５の方が好ましい特性を示している。また、非磁性層の膜厚が１．４ｎｍ以上であれば、層間相互作用を非常に小さくできることがわかる。このことから、スイッチング磁界を小さくできることが予想される。
【００９６】
（実施例２）
種々のアモルファス磁性合金を用いて、図３から反強磁性層を除いた構造を有する磁気抵抗効果素子を作製し、スイッチング磁界（保磁力）の平均値Ｈｃのアニール温度依存性を調べた。
【００９７】
熱酸化Ｓｉ基板上に下地電極としてＴａ／Ｃｕ／Ｔａを形成した後、磁気記録層としてアモルファス磁性層／非磁性層／アモルファス磁性層、トンネルバリア層としてＡｌＯ_ｘ、ピン層としてＣｏ_９Ｆｅ、カバー層としてＴａ、上部電極としてＴａ／ＡｌＣｕ／Ｔａを形成した。各層はスパッタリングにより成膜した。トンネルバリア層はＡｌをスパッタリングした後、酸化することにより形成した。また、ピン層および磁気記録層のアモルファス磁性層は磁場中で成膜した。トンネル接合の加工を、エキシマステッパとイオンミリングを用いて行い、１００個の素子を作製した。
【００９８】
素子作製後、所定温度で１時間、磁場中アニールを行い、スイッチング磁界の絶対値（１００個の素子の平均）を評価した。
【００９９】
図１３〜図１７は、以下の構造を有する磁気記録層を有する素子についての結果である。
【０１００】
図１３：（Ｃｏ_０．９０Ｆｅ_０．１０）_８５Ｂ_１５（３ｎｍ）／Ｒｕ／（Ｃｏ_０．９０Ｆｅ_０．１０）_８５Ｂ_１５（５ｎｍ）、図１３（ａ）はＲｕ（１．９ｎｍ）、図１０はＲｕ（２．４５ｎｍ）
図１４：［（Ｃｏ_０．９５Ｆｅ_０．０５）_０．９５Ｎｂ_０．０５］_８５Ｂ_１５（３ｎｍ）／Ｒｕ／［（Ｃｏ_０．９５Ｆｅ_０．０５）_０．９５Ｎｂ_０．０５］_８５Ｂ_１５（５ｎｍ）、図１４（ａ）はＲｕ（１．９ｎｍ）、図１４（ｂ）はＲｕ（２．４５ｎｍ）
図１５：Ｆｅ_８３．５Ｃｕ_１Ｎｂ_３Ｓｉ_３．５Ｂ_９（３ｎｍ）／Ｒｕ／Ｆｅ_８３．５Ｃｕ_１Ｎｂ_３Ｓｉ_３．５Ｂ_９（５ｎｍ）、図１５（ａ）はＲｕ（１．９ｎｍ）、図１５（ｂ）はＲｕ（２．４５ｎｍ）
図１６：Ｆｅ_９０Ｃｕ_１Ｚｒ_７Ｂ_２（３ｎｍ）／Ｒｕ／Ｆｅ_９０Ｃｕ_１Ｚｒ_７Ｂ_２（５ｎｍ）、図１６（ａ）はＲｕ（１．９ｎｍ）、図１６（ｂ）はＲｕ（２．４５ｎｍ）
Ｒｕの膜厚が１．９ｎｍである場合には２層のアモルファス磁性層間には弱い強磁性結合が生じ、Ｒｕの膜厚が２．４５ｎｍである場合には２層のアモルファス磁性層間には弱い反強磁性結合が生じていると考えられる。
【０１０１】
図１７は比較例であり、（Ｃｏ_０．９０Ｆｅ_０．１０）_８０Ｂ_２０（３ｎｍ）単層の磁気記録層を有する磁気抵抗効果素子についての結果である。
【０１０２】
これらの結果から、アモルファス磁性層／非磁性層／アモルファス磁性層という構造の磁気記録層を用いると、４００℃のアニール温度でもスイッチング磁界の増大が抑えられ、ＭＲＡＭに好適な特性を示した。また、スイッチング磁界のばらつき（１σ）も１０％以内におさまり、ＭＲＡＭに好適な特性を示した。
【０１０３】
さらに、図７の構造を有する強磁性二重トンネル接合素子では、スイッチング磁界のばらつき（１σ）が７％以内におさまり、ＭＲＡＭにより好適な特性を示した。
【０１０４】
（実施例３）
アモルファス磁性層／非磁性層／アモルファス磁性層の三層構造の磁気記録層を有する図８の強磁性二重トンネル接合素子を作製した。また、比較のために、単層のアモルファス磁性層からなる磁気記録層を有する強磁性二重トンネル接合素子を作製した。これらの２つの素子について、規格化ＭＲ比のバイアス電圧依存性を比較した。
【０１０５】
本実施例で作製した素子の構造は、基板：熱酸化Ｓｉ基板、下地電極：Ｔａ（５ｎｍ）／Ｃｕ（３０ｎｍ）／Ｔａ（５ｎｍ）、反強磁性層：ＮｉＦｅ（４ｎｍ）／ＩｒＭｎ（１０ｎｍ）、ピン層：Ｃｏ_９Ｆｅ（３ｎｍ）、非磁性層：Ｒｕ（１ｎｍ）、フィックス層：Ｃｏ_９Ｆｅ（３ｎｍ）、トンネルバリア層：ＡｌＯ_ｘ（１．４ｎｍ）、磁気記録層（フリー層）：Ｃｏ_７０．５Ｆｅ_４．７Ｓｉ_１５Ｂ_１０（２ｎｍ）／Ｒｕ（１．３ｎｍ）／Ｃｏ_７０．５Ｆｅ_４．７Ｓｉ_１５Ｂ_１０（２ｎｍ）、トンネルバリア層：ＡｌＯ_ｘ（１．４ｎｍ）、フィックス層：Ｃｏ_９Ｆｅ（３ｎｍ）、非磁性層：Ｒｕ（１ｎｍ）、ピン層：Ｃｏ_９Ｆｅ（３ｎｍ）、反強磁性層：ＩｒＭｎ（１０ｎｍ）、カバー層：Ｔａ、上部電極：Ｔａ（５ｎｍ）／Ｃｕ（３０ｎｍ）／Ｔａ（５ｎｍ）である。
【０１０６】
比較のために作製した素子は、磁気記録層（フリー層）が単層のＣｏ_７０．５Ｆｅ_４．７Ｓｉ_１５Ｂ_１０（２ｎｍ）からなっているものである。
【０１０７】
図１８（ａ）および（ｂ）に規格化ＭＲ比のバイアス電圧依存性を示す。図１８（ａ）は比較例の結果、図１８（ｂ）は実施例３の結果である。図１８（ａ）および（ｂ）からわかるように、単層のアモルファス磁性層からなる磁気記録層を有する強磁性二重トンネル接合素子（ａ）に比べて、アモルファス磁性層／非磁性層／アモルファス磁性層の三層構造の磁気記録層を有する強磁性二重トンネル接合素子（ｂ）は、規格化ＭＲ比のバイアス依存性が改善されている。したがって、図１８（ｂ）の素子は大きな信号出力が得られ、ＭＲＡＭとしてより好ましい特性を示すことがわかる。
【０１０８】
（実施例４）
種々のアモルファス磁性合金を用いて図２に示す構造を有する磁気抵抗効果素子を作製し、素子の幅とスイッチング磁界との関係を調べた。
【０１０９】
本実施例で作製した素子の構造は、基板：熱酸化Ｓｉ基板、下地電極：Ｔａ／Ｃｕ／Ｔａ、反強磁性層：Ｉｒ_２３Ｍｎ_７７（１０ｎｍ）、ピン層：Ｃｏ_９０Ｆｅ_１０（３ｎｍ）、非磁性層：Ｒｕ（０．９ｎｍ）、フィックス層：Ｃｏ_９０Ｆｅ_１０（３ｎｍ）、トンネルバリア層：ＡｌＯ_ｘ（１．２ｎｍ）、磁気記録層（詳細については後述する）、カバー層：Ｔａ、上部電極：Ｔａ／Ｃｕ／Ｔａである。各層はスパッタリングにより成膜した。トンネルバリア層はＡｌをスパッタリングした後、酸化することにより形成した。また、ピン層および磁気記録層のアモルファス磁性層は磁場中で成膜した。トンネル接合の加工を、エキシマステッパとイオンミリングを用いて行い、１００個の素子を作製した。素子作製後、３２５℃で磁場中アニールを行い、オートプロ−バを用いてＭＲ曲線を測定して統計処理を行い、素子の幅（ＴＭＲ幅）とスイッチング磁界との関係を調べた。
【０１１０】
磁気記録層の構造は以下の通りである。
１（参考例）：Ｃｏ_２５Ｆｅ_３５Ｎｉ_４０（１．８ｎｍ）／Ｒｕ（１．７ｎｍ）／Ｃｏ_２５Ｆｅ_３５Ｎｉ_４０（１．８ｎｍ）
２：Ｃｏ_７０．５Ｆｅ_４．７Ｓｉ_１５Ｂ_１０（２ｎｍ）／Ｒｕ（１．２ｎｍ）／Ｃｏ_７０．５Ｆｅ_４．７Ｓｉ_１５Ｂ_１０（２ｎｍ）
３：Ｃｏ_７０．５Ｆｅ_４．７Ｓｉ_１５Ｂ_１０（２ｎｍ）／Ｒｕ（１．８ｎｍ）／Ｃｏ_７０．５Ｆｅ_４．７Ｓｉ_１５Ｂ_１０（２ｎｍ）
４：Ｃｏ_７０．５Ｆｅ_４．７Ｓｉ_１５Ｂ_１０（２ｎｍ）／Ｒｕ（２．２ｎｍ）／Ｃｏ_７０．５Ｆｅ_４．７Ｓｉ_１５Ｂ_１０（２ｎｍ）
５：Ｆｅ_７３．５Ｃｕ_１Ｎｂ_３Ｓｉ_１３．５Ｂ_９（２ｎｍ）／Ｃｕ（２．８ｎｍ）／Ｆｅ_７３．５Ｃｕ_１Ｎｂ_３Ｓｉ_１３．５Ｂ_９（２ｎｍ）
６：Ｃｏ_８７Ｎｂ_５Ｚｒ_８（２ｎｍ）／Ｉｒ（１．２ｎｍ）／Ｃｏ_８７Ｎｂ_５Ｚｒ_８（２ｎｍ）
７：Ｃｏ_８４Ｆｅ_２Ｎｂ_１４（２ｎｍ）／Ｃｕ（２．８ｎｍ）／Ｃｏ_８４Ｆｅ_２Ｎｂ_１４（２ｎｍ）
８：Ｆｅ_９０Ｃｕ_１Ｚｒ_７Ｂ_２（２ｎｍ）／Ｗ（２ｎｍ）／Ｆｅ_９０Ｃｕ_１Ｚｒ_７Ｂ_２（２ｎｍ）
比較例として、Ｘ：単層のＣｏ_３５Ｆｅ_２５Ｎｉ_４０（２ｎｍ）からなる磁気記録層を有する素子、およびＹ：単層のアモルファス磁性体（Ｃｏ_９０Ｆｅ_１０）_８０Ｂ_２０（２ｎｍ）からなる磁気記録層を有する素子を作製した。
【０１１１】
図１９および図２０に結果を示す。これらの図に示されるように、アモルファス磁性層／非磁性層／アモルファス磁性層という構造の磁気記録層を用いると、スイッチング磁界のＴＭＲ幅依存性が小さいうえに、スイッチング磁界のばらつきも小さく、ＭＲＡＭに好適な特性を示した。これらの図において、丸で囲った範囲は、１ＧｂｉｔのＭＲＡＭで要求される仕様を示している。
【０１１２】
以下、上述したような磁気抵抗効果素子を用いて構成されるＭＲＡＭのアーキテクチャについて説明する。
図２１〜図２４は、磁気抵抗効果素子とＭＯＳトランジスタを用いたＭＲＡＭアーキテクチャを示す。
【０１１３】
図２１（ａ）および（ｂ）のＭＲＡＭアーキテクチャを説明する。シリコン基板上にＭＯＳトランジスタ３０が形成されている。ＭＯＳトランジスタ３０を覆う絶縁層中には、ワード線（ＷＬ）４０が一方向に延在して設けられている。また、ＭＯＳトランジスタ３０を覆う絶縁層中には、ＭＯＳトランジスタ３０に接続したプラグおよび配線が形成され、ワード線（ＷＬ）４０の上方に配線と接続するＴＭＲ素子２０が形成されている。ＴＭＲ素子２０上には、ワード線（ＷＬ）４０と直交する方向に延在するビット線（ＢＬ）５０が形成されている。
【０１１４】
図２２（ａ）および（ｂ）のＭＲＡＭアーキテクチャは、ＴＭＲ素子２０がワード線（ＷＬ）４０と配線に接続されて形成されている以外は、図２１と同様である。
【０１１５】
図２３（ａ）および（ｂ）のＭＲＡＭアーキテクチャは、ワード線（ＷＬ）４０およびビット線（５０）の一部が磁性膜４１、５１によって被覆されている以外は、図２１と同様である。
【０１１６】
図２４（ａ）および（ｂ）のＭＲＡＭアーキテクチャは、ワード線（ＷＬ）４０およびビット線（５０）の一部が磁性膜４１、５１によって被覆されている以外は、図２２と同様である。
【０１１７】
図２３および図２４に示すように、ＴＭＲセルに書き込みを行う配線の側面の少なくとも一部を軟磁性膜で被覆すると、電流磁界の増大とクロストークの低減が可能となる。
【０１１８】
図２５は、磁気抵抗効果素子とダイオードを用いたＭＲＡＭアーキテクチャを示す。一方向に延在する読み出し／書き込みデジット線（ＤＬ）１１０と、デジット線１１０に直交する方向に延在する読み出し／書き込みビット線（ＢＬ）１２０との間に、ダイオード６０と磁気抵抗効果素子２０の積層体が設けられている。デジット線（ＤＬ）１１０にはトランジスタ（ＳＴｗ）１３０が、ビット線（ＢＬ）１２０にはトランジスタ（ＳＴＢ）１４０がそれぞれ接続され、さらにトランジスタ（ＳＴｗ）１３０はセンスアンプ（ＳＡ）３００に接続されている。
【０１１９】
図２６は、磁気抵抗効果素子をはしご型配置したＭＲＡＭアーキテクチャを示す。一方向に延在する書き込みデジット線（ＤＬ）１５０と、デジット線１５０に直交する方向に延在する読み出しビット線（ＢＬｒ）１６０および書き込みビット線（ＢＬｗ）１７０が形成され、読み出しビット線（ＢＬｒ）１６０と書き込みビット線（ＢＬｗ）１７０との間に磁気抵抗効果素子２０が設けられている。読み出しビット線（ＢＬｒ）１６０にはトランジスタ（ＳＴ）１８０が、書き込みビット線（ＢＬｗ）１７０にはトランジスタ（ＳＴ）１９０がそれぞれ接続され、さらにトランジスタ１８０はセンスアンプ（ＳＡ）３００に接続されている。
【０１２０】
図２７は、磁気抵抗効果素子を単純マトリックス型配置したＭＲＡＭアーキテクチャを示す。一方向に延在する書き込みデジット線（ＤＬ）２００と読み出しビット線（ＢＬｒ）２１０とが上下に配置され、これらに直交する方向に延在する書き込みビット線（ＢＬｗ）２２０が形成され、読み出しビット線（ＢＬｒ）２１０と書き込みビット線（ＢＬｗ）２２０との間に磁気抵抗効果素子２０が設けられている。読み出しビット線（ＢＬｒ）２１０にはトランジスタ（ＳＴ２）２３０が、書き込みビット線（ＢＬｗ）２２０にはトランジスタ（ＳＴ１）２４０がそれぞれ接続され、さらにトランジスタ２３０はセンスアンプ（ＳＡ）３００に接続されている。
【０１２１】
図２８は、磁気抵抗効果素子を単純マトリックス型配置したＭＲＡＭアーキテクチャを示す。一方向に延在する書き込みデジット線（ＤＬ）２５０と読み出しビット線（ＢＬｒ）２６０とが並列に配置され、これらに直交する方向に延在する書き込みビット線（ＢＬｗ）２７０が形成され、読み出しビット線（ＢＬｒ）２６０と書き込みビット線（ＢＬｗ）２７０との間に磁気抵抗効果素子２０が設けられている。読み出しビット線（ＢＬｒ）２６０にはトランジスタ（ＳＴ２）２８０が、書き込みビット線（ＢＬｗ）２７０にはトランジスタ（ＳＴ１）２９０がそれぞれ接続され、さらにトランジスタ２８０はセンスアンプ（ＳＡ）３００に接続されている。
【０１２２】
【発明の効果】
以上詳述したように本発明によれば、スイッチング磁界のばらつきが小さく，強磁性トンネル接合のビットサイズを微小化してもスイッチング磁界の増大を抑制でき、熱安定性に優れ、信頼性のある磁気抵抗効果素子、およびそれを用いた磁気メモリを提供できる。
【図面の簡単な説明】
【図１】本発明の実施形態に係るボトム型の強磁性一重トンネル接合素子の模式図。
【図２】本発明の実施形態に係るボトム型の強磁性一重トンネル接合素子の模式図。
【図３】本発明の実施形態に係るトップ型の強磁性一重トンネル接合素子の模式図。
【図４】本発明の実施形態に係るトップ型の強磁性一重トンネル接合素子の模式図。
【図５】本発明の実施形態に係る強磁性二重トンネル接合素子の模式図。
【図６】本発明の実施形態に係る強磁性二重トンネル接合素子の模式図。
【図７】本発明の実施形態に係る強磁性二重トンネル接合素子の模式図。
【図８】本発明の実施形態に係る強磁性二重トンネル接合素子の模式図。
【図９】本発明の実施形態に係る磁気抵抗効果素子の平面図。
【図１０】耐熱性試験のために作製した磁気抵抗効果素子の模式図。
【図１１】耐熱性試験のために作製した磁気抵抗効果素子の模式図。
【図１２】実施例１における磁気抵抗効果素子について、非磁性層の膜厚と層間相互作用との関係を示す図。
【図１３】実施例２における磁気抵抗効果素子について、スイッチング磁界の絶対値を示す図。
【図１４】実施例２における磁気抵抗効果素子について、スイッチング磁界の絶対値を示す図。
【図１５】実施例２における磁気抵抗効果素子について、スイッチング磁界の絶対値を示す図。
【図１６】実施例２における磁気抵抗効果素子について、スイッチング磁界の絶対値を示す図。
【図１７】比較例の磁気抵抗効果素子について、スイッチング磁界の絶対値を示す図。
【図１８】実施例３における磁気抵抗効果素子について、規格化ＭＲ比のバイアス電圧依存性を示す図。
【図１９】実施例４における磁気抵抗効果素子について、素子の幅とスイッチング磁界との関係を示す図。
【図２０】実施例４における磁気抵抗効果素子について、素子の幅とスイッチング磁界との関係を示す図。
【図２１】磁気抵抗効果素子とＭＯＳトランジスタを用いたＭＲＡＭアーキテクチャを示す図。
【図２２】磁気抵抗効果素子とＭＯＳトランジスタを用いたＭＲＡＭアーキテクチャを示す図。
【図２３】磁気抵抗効果素子とＭＯＳトランジスタを用いたＭＲＡＭアーキテクチャを示す図。
【図２４】磁気抵抗効果素子とＭＯＳトランジスタを用いたＭＲＡＭアーキテクチャを示す図。
【図２５】磁気抵抗効果素子とダイオードを用いたＭＲＡＭアーキテクチャを示す図。
【図２６】磁気抵抗効果素子をはしご型配置したＭＲＡＭアーキテクチャを示す図。
【図２７】磁気抵抗効果素子を単純マトリックス型配置したＭＲＡＭアーキテクチャを示す図。
【図２８】磁気抵抗効果素子を単純マトリックス型配置したＭＲＡＭアーキテクチャを示す図。
【符号の説明】
１…下地電極
２…反強磁性層
３…磁化固着層（ピン層）
４…トンネルバリア層
５…磁気記録層（フリー層）
５ａ…アモルファス磁性層
５ｂ…非磁性層
５ｃ…アモルファス磁性層
６…トンネルバリア層
７…磁化固着層（ピン層）
８…反強磁性層
９…カバー層（ハードマスク）
１０…上部電極[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetoresistive element and a magnetic memory, and more particularly to a large-capacity magnetic memory having a memory array including a ferromagnetic tunnel junction type magnetoresistive element, and particularly having excellent thermal stability.
[0002]
[Prior art]
2. Description of the Related Art A magnetoresistive element using a magnetic film is used for a magnetic head, a magnetic sensor, and the like, and is further proposed to be used for a solid-state magnetic memory (Magnetic Random Access Memory (MRAM)). .
[0003]
2. Description of the Related Art In recent years, in a sandwich structure film in which one dielectric is inserted between two magnetic metal layers, a magnetoresistance effect element using a tunnel current by flowing a current perpendicular to the film surface, a so-called ferromagnetic tunnel junction element : TMR element (tunneling magneto-resistive element) has been proposed. In a ferromagnetic tunnel junction device, a magnetoresistance ratio of 20% or more is obtained. Therefore, the possibility of applying the ferromagnetic tunnel junction device to the MRAM has been increased.
[0004]
In this ferromagnetic tunnel junction device, a thin Al (aluminum) layer having a thickness of 0.6 to 2.0 nm is formed on a ferromagnetic layer, and the surface thereof is exposed to an oxygen glow discharge or an oxygen gas.₂O₃Is formed by forming a tunnel barrier layer made of and then forming another ferromagnetic layer on the tunnel barrier layer.
[0005]
Further, a ferromagnetic single tunnel junction having a structure in which an antiferromagnetic layer is added to one ferromagnetic layer of the ferromagnetic single tunnel junction to form a magnetization fixed layer has been proposed.
[0006]
Further, a ferromagnetic tunnel junction via magnetic particles dispersed in a dielectric and a ferromagnetic double tunnel junction (continuous film) have also been proposed.
[0007]
Even in these ferromagnetic tunnel junction devices, a magnetoresistance change ratio of 20 to 50% can be obtained, and even if the voltage value applied to the ferromagnetic tunnel junction device to obtain a desired output voltage value is increased. Since the decrease in the rate of change in magnetoresistance is suppressed, the possibility of application to MRAM has been increased.
[0008]
A magnetic memory using a ferromagnetic single tunnel junction or a ferromagnetic double tunnel junction is nonvolatile, has a fast write / read time of 10 nanoseconds or less, and has a rewrite frequency of 10 nanoseconds or less.^FifteenIt has the potential described above. In particular, in the magnetic memory using the ferromagnetic double tunnel junction, as described above, even if the voltage value applied to the ferromagnetic tunnel junction element is increased to obtain a desired output voltage value, the decrease in the magnetoresistance ratio can be suppressed. Therefore, a large output voltage can be obtained, and favorable characteristics as a memory element are exhibited.
[0009]
In order to suppress the variation of the switching magnetic field of the magnetic memory, the free layer is made of an amorphous magnetic material (Co).₉₀Fe₁₀)_1-xB_xIt has been proposed to use (for example, see Non-Patent Document 1). However, since the Co—Fe—B amorphous magnetic layer is crystallized at 350 ° C. or higher, the thermal stability at 400 ° C. or higher and the fabrication of MRAM having a wiring process are limited in thermal stability, and the variation in switching magnetic field is limited. There is a problem of increasing. In addition, if the bit size is reduced to increase the capacity, a problem of thermal fluctuation occurs, which may cause spin information to disappear, and an increase in a switching magnetic field accompanying the reduction in the bit size may cause a problem. come.
[0010]
Further, a ferromagnetic tunnel junction device in which an amorphous ferromagnetic layer is provided between at least one of a ferromagnetic layer (free layer) and a tunnel barrier layer and at least one between a ferromagnetic layer (fixed layer) and a tunnel barrier layer, A used magnetic memory cell is known (for example, see Patent Document 1). However, even in the device of this document, there is a problem that the variation of the switching magnetic field is increased, and if the bit size is reduced to increase the capacity, a problem of thermal fluctuation occurs, and the spin information may be lost. In addition to the above, problems such as an increase in the switching magnetic field due to the miniaturization of the bit size become problems.
[0011]
As described above, in order to increase the capacity of a magnetic memory, a magnetoresistive element having a large MR ratio, a small switching magnetic field, and excellent thermal stability is required even if the bit size is reduced. You.
[0012]
[Non-patent document 1]
Intermag Europe 2002, BB05, April 2002
[0013]
[Patent Document 1]
JP 2001-68760 A
[0014]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetoresistive element which has excellent thermal stability, has a small variation in a switching magnetic field, and can suppress an increase in a switching magnetic field even if the bit size of a ferromagnetic tunnel junction is reduced, and a magnetic memory using the same. Is to provide.
[0015]
[Means for Solving the Problems]
A magnetoresistive effect element according to one embodiment of the present invention includes at least one tunnel barrier layer, a magnetic recording layer and a magnetization fixed layer provided with the tunnel barrier layer interposed therebetween, and the magnetic recording layer has at least two layers. And a non-magnetic layer interposed therebetween.
[0016]
A magnetic memory according to another aspect of the present invention is provided with a first wiring extending in a first direction, and provided above the first wiring and extending in a direction intersecting the first direction. A second wiring, provided between the first wiring and the second wiring, at least one tunnel barrier layer, and a magnetic recording layer and a magnetization fixed layer provided with the tunnel barrier layer interposed therebetween. Wherein the magnetic recording layer includes at least two amorphous magnetic layers and a magnetoresistive element including a nonmagnetic layer interposed therebetween.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
A magnetoresistive element according to an embodiment of the present invention has at least one tunnel barrier layer, a magnetic recording layer and a magnetization fixed layer provided with the tunnel barrier layer interposed therebetween, and the magnetic recording layer has at least two magnetic recording layers. Includes an amorphous magnetic layer and a non-magnetic layer inserted therebetween.
[0019]
In the embodiment of the present invention, the magnetic recording layer (free layer) is not limited to a three-layer film of an amorphous magnetic layer / non-magnetic layer / amorphous magnetic layer, but may be an amorphous magnetic layer / non-magnetic layer / amorphous magnetic layer / non-magnetic layer. A five-layer film of an amorphous magnetic layer or a multi-layer film of more layers may be used. The amorphous magnetic layer included in the magnetic recording layer (free layer) is preferably an even layer.
[0020]
In the present specification, the amorphous magnetic layer forming the magnetic recording layer (free layer) includes not only a magnetic layer in which crystal grains are not substantially observed but also a microcrystalline magnetic layer including fine crystal grains.
[0021]
1 to 8 show examples of a magnetoresistive element according to an embodiment of the present invention. 1 to 4 show a ferromagnetic single tunnel junction device, and FIGS. 5 to 8 show a ferromagnetic double tunnel junction device.
[0022]
FIG. 1 shows a bottom type ferromagnetic single tunnel junction device having an antiferromagnetic layer formed below. The magnetoresistive element shown in FIG. 1 has a substrate (not shown), a base electrode 1, an antiferromagnetic layer 2, a pinned layer (pin layer) 3, a tunnel barrier layer 4, an amorphous magnetic layer 5a and a nonmagnetic layer. A magnetic recording layer (free layer) 5 having a three-layer structure of 5b / amorphous magnetic layer 5c, a cover layer (hard mask) 9, and an upper electrode 10 are formed.
[0023]
FIG. 2 has the same structure as FIG. 1 except that the magnetization fixed layer 3 has a three-layer structure of a pinned layer 3a / non-magnetic layer 3b / fixed layer 3c.
[0024]
FIG. 3 shows a top type ferromagnetic single tunnel junction device having an antiferromagnetic layer formed thereon. The magnetoresistive element shown in FIG. 3 has a magnetic recording layer 5 having a three-layer structure of a base electrode 1, an amorphous magnetic layer 5a / a nonmagnetic layer 5b / amorphous magnetic layer 5c, a tunnel barrier layer 6, and a single layer on a substrate (not shown). A pinned layer 7, an antiferromagnetic layer 8, a cover layer (hard mask) 9, and an upper electrode 10 are formed.
[0025]
FIG. 4 has the same configuration as FIG. 3 except that the magnetization fixed layer 7 has a three-layer structure of a pinned layer 7a / non-magnetic layer 7b / fixed layer 7c.
[0026]
FIG. 5 shows a ferromagnetic double tunnel junction device. The magnetoresistive element shown in FIG. 5 has a base electrode 1, an antiferromagnetic layer 2, a pinned magnetization layer (pin layer) 3, a tunnel barrier layer 4, an amorphous magnetic layer 5a and a nonmagnetic layer on a substrate (not shown). 5b / a magnetic recording layer (free layer) 5 having a three-layer structure of an amorphous magnetic layer 5c, a tunnel barrier layer 6, a single-layer magnetization fixed layer (pin layer) 7, an antiferromagnetic layer 8, a cover layer (hard mask) 9 and an upper electrode 10 are formed.
[0027]
6 has the same structure as that of FIG. 5 except that the lower magnetization pinned layer 3 has a three-layer structure of a pinned layer 3a / non-magnetic layer 3b / fixed layer 3c.
[0028]
FIG. 7 has the same structure as that of FIG. 5 except that the upper magnetization pinned layer 7 has a three-layer structure of a fix layer 7a / a nonmagnetic layer 7b / a pinned layer 7c.
[0029]
FIG. 8 shows a lower pinned layer 3 having a three-layered structure of a pinned layer 3a / non-magnetic layer 3b / fixed layer 3c, and an upper pinned layer 7 having a three-layered structure of a fixed layer 7a / non-magnetic layer 7b / pinned layer 7c. Except for the structure, it has the same structure as FIG.
[0030]
As described above, when an amorphous magnetic layer / non-magnetic layer / amorphous magnetic layer is used for the magnetic recording layer (free layer), it is possible to suppress an increase in the switching magnetic field even when the bit size of the ferromagnetic tunnel junction is reduced. In addition, since the bias dependence of the MR ratio and the dependence of the interlayer interaction on the thickness of the nonmagnetic layer are small, a highly reliable magnetoresistive element (ferromagnetic tunnel junction element) having a large margin can be provided.
[0031]
Next, materials and the like used for the magnetoresistance effect element according to the embodiment of the present invention will be described.
[0032]
The amorphous magnetic layer forming the magnetic recording layer (free layer) has the following general formula
Co-Fe-AA, Co-Fe-AA-AA2, Fe-AA-AA2, Co-AA-AA2, Co-Mn-AA-AA2, Fe-Cu-AA-AA2, and Co-Fe-Ni-AA
(Where AA or AA2 is at least one selected from the group consisting of B, Si, Ge, Zr, Nb, P, Mo, Ta, N, C, Ti, Al, W, V, rare earth and nitrogen) Is an element of
Is used. The amorphous magnetic layer may contain 20 at% or more of AA or AA2 which is an additional element other than the 3d magnetic element (Co, Fe, Ni).
[0033]
Since these amorphous alloys have a high crystallization temperature (thermal stability) and are also sputtered on the tunnel barrier layer with a uniform thickness, the amorphous magnetic layer / non-magnetic layer / The structure of the amorphous magnetic layer is maintained, the magnetostriction is small, and the variation in the switching magnetic field is suppressed. More specific materials for the amorphous magnetic layer will be described later in detail.
[0034]
Although the non-magnetic layer is not particularly limited, it is preferable to use Ru, Cu, Ir, Cr, Ag, Au, Pt, TiW, W, TaN, and TiN. The thickness of the nonmagnetic layer is preferably at least 1.4 nm.
[0035]
Also, the magnetization directions of the two amorphous magnetic layers included in the magnetic recording layer are preferably antiparallel, and the interaction between the two amorphous magnetic layers via the non-magnetic layer is typically from −2000 Oe to 500 Oe. When the interaction between the two amorphous magnetic layers is -2000 Oe to 500 Oe, the switching magnetic field is reduced, and the increase in the switching magnetic field can be suppressed even if the bit size is reduced. In addition, when the amorphous magnetic layer is used, the magnitude of the above-described interaction can be easily obtained, and the margin for the film thickness of the non-magnetic layer is widened.
[0036]
As the tunnel barrier layer, it is preferable to use oxides or nitrides of Al, Mg, Ga, In, Sr, Ba, rare earths, or alloys thereof. Specifically, Al₂O₃(Aluminum oxide), SiO₂(Silicon oxide), MgO (magnesium oxide), AlN (aluminum nitride), Bi₂O₃(Bismuth oxide), MgF₂(Magnesium fluoride), CaF₂(Calcium fluoride), SrTiO₂(Titanium oxide / strontium), AlLaO₃(Lanthanum aluminum oxide), Al-NO (alnium oxynitride), GaO, InO, or the like can be used. When a tunnel barrier layer is formed using these materials, a tunnel junction having a high MR ratio can be manufactured because the barrier height is high.
[0037]
As described above, the magnetization fixed layer may have a three-layer structure of a ferromagnetic layer (pin layer) / non-magnetic layer / ferromagnetic layer (fix layer). In this case, it is preferable that the thickness of the ferromagnetic layer (fix layer) close to the tunnel barrier layer be larger than the thickness of the ferromagnetic layer (pin layer) far from the tunnel barrier layer. When such a structure is used, the orange peel interaction between the recording layer and the fix layer can be canceled by a stray field corresponding to a film thickness difference between the fix layer and the pin layer.
[0038]
In addition, in the structure of FIG. 6, by keeping the upper pinned layer thickness ≒ (the thickness of the lower fixed layer−the thickness of the lower pinned layer), the shift of the hysteresis loop can be completely canceled.
[0039]
The amorphous magnetic layer can be used not only for the magnetic recording layer but also for the pinned layer and the fixed layer. The thickness of the single amorphous magnetic layer is preferably 0.5 to 5 nm. The amorphous magnetic layer has good film continuity and can obtain good magnetic properties up to a thickness of 0.5 nm. However, if the film thickness is less than 0.5 nm, a superparamagnetic MH curve may occur, which is not preferable for MRAM. On the other hand, in a three-layer recording layer of an amorphous magnetic layer / non-magnetic layer / amorphous magnetic layer, the thickness of one amorphous magnetic layer is preferably 5 nm or less. Since the amorphous magnetic layer has a saturation magnetization value smaller than that of the Co, Fe, and Ni alloys, when the TMR width is reduced to 0.6 μm, the switching magnetic field is increased to about several tens Oe even when the film thickness is increased to about 5 nm. However, if the film thickness exceeds 5 nm, the switching magnetic field may be increased.
[0040]
These magnetic materials include Ag (silver), Cu (copper), Au (gold), Al (aluminum), Mg (magnesium), Si (silicon), Bi (bismuth), Ta (tantalum), (Boron), C (carbon), O (oxygen), N (nitrogen), Pd (palladium), Pt (platinum), Zr (zirconium), Ir (iridium), W (tungsten), Mo (molybdenum), Nb By adding a nonmagnetic element such as (niobium), various physical properties such as crystallinity, mechanical properties, and chemical properties may be adjusted in addition to magnetic properties.
[0041]
As the substrate on which the magnetoresistive element is formed, for example, Si (silicon), SiO₂(Silicon oxide), Al₂O₃Various substrates such as (aluminum oxide), spinel, and AlN (alnium nitride) can be used.
[0042]
A base electrode layer may be provided on the substrate, or an upper electrode layer, a protective layer, and the like may be provided on the magnetoresistive element. Materials for the base electrode layer, the upper electrode layer, and the protective layer include Ta (tantalum), Ti (titanium), Pt (platinum), Pd (palladium), Au (gold), Ti (titanium) / Pt (platinum), Ta (tantalum) / Pt (platinum), Ti (titanium) / Pd (palladium), Ta (tantalum) / Pd (palladium), Cu (copper), Al (aluminum) -Cu (copper), Ru (ruthenium), Ir (iridium), Os (osmium) or the like is used.
[0043]
The magnetoresistive effect element according to the embodiment of the present invention can be formed using ordinary thin film forming means such as various sputtering methods, vapor deposition methods, and molecular beam epitaxial methods. The processing of the ferromagnetic tunnel junction can be performed using an excimer stepper and ion milling.
[0044]
FIGS. 9A to 9E show plan views of the processed magnetoresistive element. As shown in these figures, it is preferable to use a low aspect ratio magnetoresistive element having a ratio of width (W) to length (L) of 2 or less for each magnetoresistive cell (TMR cell). . In these TMR cells, uniaxial anisotropy can be easily imparted to the amorphous magnetic layer by utilizing film formation in a magnetic field and annealing in a magnetic field in addition to shape anisotropy.
[0045]
Hereinafter, the amorphous alloy suitably used in the embodiment of the present invention will be more specifically described using a general formula. In addition, in the following general formulas, the numerical value range of the subscript indicating the composition represents atomic%.
[0046]
[1] Co-based amorphous alloy (metal-metalloid system)
(Co_1-abM_aT_b)_100-cdX1_cX2_d
(Where M is at least one selected from Fe, Ni and Mn, T is at least one selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and Cu, X1 is B, X2 is at least one selected from Si, Ge, C, Ga, N, F, O, Al, and Sn, and 0.03 ≦ a ≦ 0.20 (when M is Ni) a is 0.03 ≦ a ≦ 0.35), 0 ≦ b ≦ 0.10, 5 ≦ c ≦ 30, 0 ≦ d ≦ 25, and 15 ≦ c + d ≦ 30).
[0047]
For example, (Co_0.95Fe_0.05)₇₀Si₁₆B₁₄, (Co_0.90Fe_0.05Nb_0.04Cr_0.01)₇₅Si₁₂B_Thirteen, (Co_0.88Fe_0.05Ti_0.07)₇₉Si₁₀B₁₁, (Co_0.90Fe_0.05Mo_0.03W_0.02)₇₆Si₁₀B₁₁Al₃, (Co_0.82Fe_0.09Ni_{0.0 6}Mo_0.03)₇₃Si₇Ge₃B₇P₁₀, (Co_0.88Mn_0.09Ta_0.03)₇₆Si₉B₁₄C₁, (Co_0.90Fe_0.05Zr_0.05)₇₂Si₁₀B₁₀O₄N₄, (Co_0.88Mn_0.09Mo_0.03)₇₆Si₁₁B₁₂F₁, (Co_0.90Fe_0.04W_0.06)₇₇Si₁₂B₁₀Ga₁, (Co_0.88Fe_0.06Hf_0.03V_0.03)₇₄Si₁₂B_ThirteenSn₁And the like.
[0048]
[2] Co-based amorphous alloy (metal-metal system)
(Co_1-aT_a)_100-bcM_bX3_c
(Where T is at least one selected from Fe, Mn and Ni, M is at least one selected from Ti, Nb, Ta, Zr, Hf, Mo and W, and M ′ is selected from Cr, V and Cu. X3 is at least one selected from B, P, C, O, N, Si, F, Ge, Ga, Sn, and Al, 0 ≦ a ≦ 0.1, 6 ≦ b ≦ 20, 0 ≤ c ≤ 8).
[0049]
For example, Co₈₆Nb₆Zr₈, Co₈₆Zr₆B₆P₂, Co₈₆Ta₇Zr₆Cu₁, Co₈₆Ta₇Zr₆Ge₁, Co₈₁Mn₄Nb_Fifteen, Co₈₄Mn₄Ta₁₀Si₂, Co₆₉Ni₁₀Fe₆Nb_ThirteenHf₂, Co₈₅Fe₂Nb₁₄C₁, Co₇₉Fe₄Nb_FifteenW₁F₁, Co₈₅Nb₇Ti₇O₁, Co₈₅Nb₇Ti₇F₁, Co₉₀Ta₅Zr₅N₁, Co₈₆Nb₆Zr₃Mo₃Cr₁V₁, Co₉₀Ta₅Zr₄Ga₁N₁, Co₈₄Ta₈Zr₇Sn₁, Co₈₄Ta₈Zr₇Al₁And the like.
[0050]
[3] FeCo-based microcrystalline magnetic alloy
T_100-abcA_aM_bX4_c
(Where T is at least one selected from Fe, Co, and Ni, A is at least one selected from Cu, Ag, and Au, M is Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, X4 is at least one selected from B, Si, P, C, O, N, F, Ge, Ga, Sn, Al, Pt, and Rh.Pd; 0 ≦ a ≦ 8, 2 ≦ b ≦ 20, 2 ≦ c ≦ 35). The magnetic thin film represented by this general formula contains microcrystals having an average particle size of 5 to 100 nm. A more preferable composition range of the FeCo-based microcrystalline magnetic alloy is represented by the following two general formulas [3 '] and [3 "].
[0051]
[3 '] Fe-metalloid microcrystalline magnetic alloy (finemet type)
(Fe_1-aT_a)_100-bcdcefA_bM_cSi_dB_eX5_f
(Where T is at least one selected from Ni, Co and Mn, A is at least one selected from Cu, Ag and Au, M is Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, X5 is at least one selected from P, C, O, N, F, Ge, Ga, Sn, and Al; 0 ≦ a ≦ 0.1, 0.01 ≦ b ≦ 5; 0.1 ≦ c ≦ 10, 8 ≦ d ≦ 20, 4 ≦ e ≦ 15, 0 ≦ f ≦ 5). The magnetic thin film represented by this general formula contains microcrystals having an average particle size of 5 to 100 nm, and the proportion of the microcrystals is 50% by volume or more.
[0052]
For example, Fe₇₃Cu₁Nb₃Si₁₇B₆, Fe₇₂Cu₁Nb₄Si₁₆B₇, Fe₇₂Cu₂Ta₂Si_FifteenB₈C₁, Fe₇₀Cu₃W₂Si₁₄B₈N₃, Fe₇₁Ag₁Zr₅Si_FifteenB₆P₂, Fe₇₂Cu₁Ti₅Si_FifteenB₇, Fe₆₉Au₁V₆Si_FifteenB₇O₂, Fe₇₀Co₃Cu₂Hf₄Si₁₆B₅, Fe₇₀Ni₃Cu₂Mo₃Cr₁Si_FifteenB₆, Fe₇₂Cu₁Nb₃Si_FifteenB₆N₂, Fe₇₃Cu₁Nb₃Si_FifteenB₆F₁, Fe₇₂Cu₁Nb₃Si_FifteenB₆Ge₃, Fe₇₂Cu₁Nb₃Si_FifteenB₆Al₃, Fe₇₀Mn₂Cu₁Nb₃Si₁₆B₇And the like.
[0053]
[3 "] (FeCo) -metal- (B, C, N, etc.) (nanopalm system)
T_100-abcdM_aM '_bX6_cX7_d
(Here, T is at least one selected from Fe, Co, and Ni, M is at least one selected from Ti, Zr, Hf, V, Nb, Ta, Mo, and W, and M ′ is Cu, Ag, and Au. X6 is at least one selected from B, C, N, O, F, and P, and X7 is Si, Ge, Al, Sn, Ga, Sn, Mn, Cr, Pd, Rh, Pt. At least one selected from the group consisting of 4 ≦ a ≦ 20, 0 ≦ b ≦ 8, 2 ≦ c ≦ 20, and 0 ≦ d ≦ 5). The magnetic thin film represented by this general formula mainly comprises fine crystal grains.
[0054]
For example, Fe₉₀Zr₇B₂, Fe₉₀Cu₁Zr₇B₂, Fe₈₃Zr₆N₁₁, Fe₈₂Au₁Zr₆N₁₁, Fe₈₀Zr₆N₁₁Si₃, Fe₇₈Ta₁₀N₁₂, Fe₇₇Ta₁₀N₁₁Ge₂, Fe₇₇Ag₁Ta₁₀Cr₂N₅C₅, Fe₈₂Zr₈C₈Mn₂, Fe₇₇Ag₁Ta₁₀N₁₂, Fe₇₈Ta₁₀N₁₀F₂, Fe₇₄Nb_ThirteenC₁₁P₂, Fe₇₁Nb₁₂Al₉N₆O₂, Fe₇₇V₇Al₉N₅O₂, Co₇₉Ta8C_Thirteen, Co₇₈Ta8C_ThirteenSn₁, Co₇₈Ta8C_ThirteenGa₁, Co₈₄Fe₂Pd₂Hf₈O₆, Co₈₄Fe₂Pt₂Hf₈O₆, Co₈₄Fe₂Rh₂Hf₈O₆And the like.
[0055]
[4] FeAlSi (Sendust)
Fe_100-abcdAl_aSi_bM_cX8_d
(Where M is at least one selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Cu, Ga, Ge, Sn, and X8 is B, C, N, O, At least one selected from F and P, 3 ≦ a ≦ 9, 6 ≦ b ≦ 12, 0 ≦ c ≦ 4, 0 ≦ d ≦ 10).
[0056]
For example, Fe₈₅Al₆Si₉, Fe₈₄Al₅Si₁₀Cr₁, Fe₈₄Al₅Si₁₀Mo₁, Fe₈₄Al₅Si₁₀W₁, Fe₈₄Al₅Si₁₀Cu₁, Fe₈₄Al₅Si₁₀Mn₁, Fe₈₄Al₅Si₁₀Ti₁, Fe₈₂Al₆Si₉Zr₂F₁, Fe₈₃Al₅Si₉Hf₁B₂, Fe₈₃Al₅Si₁₀V₁O₁, Fe₈₄Al₅Si₉Nb₁N₁, Fe₈₃Al₅Si₁₀Ta₁C₁, Fe₈₄Al₅Si₁₀Ga₁, Fe₈₄Al₅Si₁₀Ge₁, Fe₈₄Al₅Si₁₀Sn₁, Fe₈₄Al₅Si₁₀Cr₁And the like.
[0057]
[5] NiFe system (permalloy system)
Ni_100-abcFe_aM_bX8_c
(Where M is at least one selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Cu, Ga, Ge, Sn, and X8 is B, C, N, O, At least one selected from F and P, 16 ≦ a ≦ 22, 0 ≦ b ≦ 5, 0 ≦ c ≦ 10).
[0058]
For example, Fe₂₀Ni₇₉Mo₁, Fe₂₀Ni₇₉Cr₁, Fe₂₀Ni₇₉W₁, Fe₂₀Ni₇₉Mn₁, Fe₁₉Ni₇₉Ti₂, Fe₁₉Ni₇₈Zr₂F₁, Fe₁₉Ni₇₈Hf₁B₂, Fe₁₉Ni₇₈V₂O₁, Fe₁₉Ni₇₈Nb₂N₁, Fe₁₉Ni₇₈Ta₂C₁, Fe₂₀Ni₇₉Ga₁, Fe₂₀Ni₇₉Ge₁, Fe₂₀Ni₇₉Sn₁And the like.
[0059]
[6] FeSi type (silicon steel type)
Fe_100-abcSi_aM_bX8_c
(Where M is at least one selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Cu, Ga, Ge, Sn, and X8 is B, C, N, O, At least one selected from F and P, 9 ≦ a ≦ 15, 0 ≦ b ≦ 5, 0 ≦ c ≦ 10).
[0060]
For example, Fe₈₈Si₁₂, Fe₈₇Si₁₂Mo₁, Fe₈₇Si₁₂W₁, Fe₈₇Si₁₂Cu₁, Fe₈₇Si₁₂Mn₁, Fe₈₇Si₁₂Ti₁, Fe₈₆Si₁₁Zr₂F₁, Fe₈₆Si₁₁Hf₁B₂, Fe₈₇Si₁₁V₁O₁, Fe₈₇Si₁₁Nb₁N₁, Fe₈₇Si₁₁Ta₁C₁, Fe₈₇Si₁₁Ga₁, Fe₈₇Si₁₁Ge₁, Fe₈₇Si₁₁Sn₁And the like.
[0061]
Next, a magnetoresistance effect element was manufactured using the amorphous magnetic alloy (or microcrystalline magnetic alloy) described so far, and the heat resistance was examined. It was confirmed that it was a suitable material. Tables 1 to 24 below show the structures and evaluation results of the manufactured magnetoresistance effect elements.
[0062]
Here, since only the heat resistance is evaluated, in addition to the magneto-resistance effect elements having the three-layered magnetic recording layer shown in FIG. 10 or FIG. A magnetoresistive element changed to an amorphous magnetic layer was manufactured. FIG. 10 is similar to FIG. 1 and FIG. 11 is similar to FIG. 5, but in each case the antiferromagnetic layer is omitted. This is because when the antiferromagnetic layer is formed, Mn diffused from the antiferromagnetic layer affects the device characteristics, so that the influence of Mn diffusion is avoided.
[0063]
The evaluation method will be described using Tables 1 to 4 as typical examples. Tables 1 and 2 show the structure (pin layer / tunnel barrier layer / magnetic recording layer, or pin layer / tunnel barrier layer / magnetic layer) of a magnetoresistive element manufactured using the amorphous magnetic alloy included in claim 2 or the like. (Recording layer / tunnel barrier layer / pin layer). For comparison, a conventional example (Co₉₀Fe₁₀)₈₀B₂₀2 also shows the structure of a magnetoresistive effect element manufactured by using (see the end of Table 2).
[0064]
Specifically, after forming Ta / Cu / Ta as a base electrode on a thermally oxidized Si substrate, the structures shown in the respective numbers of Tables 1 and 2 are formed, and Ta is used as a cover layer, and Ta / Cu is used as an upper electrode. Cu / Ta was formed. Each layer was formed by sputtering. The tunnel barrier layer was formed by oxidizing Al after sputtering. The pinned layer and the amorphous magnetic layer of the magnetic recording layer were formed in a magnetic field. Processing of the tunnel junction was performed using an excimer stepper and ion milling, and 100 devices were manufactured.
[0065]
After the device was manufactured, annealing was performed in a magnetic field at a predetermined temperature in the range of 300 to 400 ° C. for 1 hour, and the variation in the switching magnetic field was evaluated. At this time, the MR curve was measured using an auto prober, and statistical processing was performed to determine the standard deviation. Tables 3 and 4 show variations in switching (coercive force) (dHc) and variations in offset magnetic field (dHc) at each annealing temperature._off) Indicates a standard deviation value (1σ).
[0066]
Tables 3 and 4 show that when the amorphous magnetic layer described in claim 3 is used, even when the annealing temperature is 400 ° C., the variation in the switching magnetic field and the offset magnetic field can be suppressed small. This is a preferable characteristic for the MRAM. Further, when the amorphous magnetic layer was used also as the magnetization fixed layer, the variation of the switching magnetic field and the offset magnetic field was further reduced, and the characteristics more preferable as the MRAM were exhibited.
[0067]
Other tables also display the same contents as Tables 1 to 4 described above. Ie
Tables 5 to 8 show that when the above [1] Co-based amorphous alloy (metal-metalloid type) was used,
Tables 9 to 12 show that when the above [3 '] Fe-metalloid microcrystalline magnetic alloy (Finemet type) was used,
Tables 13 to 16 show that when the above [3 ″] (FeCo) -metal- (B, C, N, etc.) (nanopalm system) is used,
Tables 17 to 20 show that when the above [5] NiFe-based (permalloy-based) was used,
Tables 21 to 24 show the cases where the above [6] FeSi-based (silicon steel-based) is used. In each case, four tables form one set, the first two tables show the element structure, and the last two tables show the evaluation results.
[0068]
[Table 1]

[0069]
[Table 2]

[0070]
[Table 3]

[0071]
[Table 4]

[0072]
[Table 5]

[0073]
[Table 6]

[0074]
[Table 7]

[0075]
[Table 8]

[0076]
[Table 9]

[0077]
[Table 10]

[0078]
[Table 11]

[0079]
[Table 12]

[0080]
[Table 13]

[0081]
[Table 14]

[0082]
[Table 15]

[0083]
[Table 16]

[0084]
[Table 17]

[0085]
[Table 18]

[0086]
[Table 19]

[0087]
[Table 20]

[0088]
[Table 21]

[0089]
[Table 22]

[0090]
[Table 23]

[0091]
[Table 24]

[0092]
When the above-described magnetoresistive element is applied to a magnetic memory (MRAM), a first wiring extending in a first direction, a first wiring provided above the first wiring, and a first wiring are provided. A second wiring extending in a direction intersecting with the second wiring, and at least one tunnel barrier layer provided between the first wiring and the second wiring; and a magnetic recording medium provided with the tunnel barrier layer interposed therebetween. A magnetoresistive element having a layer and a magnetization fixed layer, wherein the magnetic recording layer includes at least two amorphous magnetic layers and a nonmagnetic layer interposed therebetween. A specific MRAM architecture will be described later in detail.
[0093]
【Example】
(Example 1)
A laminated structure of ferromagnetic layer / nonmagnetic layer / ferromagnetic layer was formed by changing the thickness of the nonmagnetic layer, and the interaction between the two ferromagnetic layers via the nonmagnetic layer was examined.
[0094]
As amorphous magnetic layer / non-magnetic layer / amorphous magnetic layer,
A: (Co₉₀Fe₁₀)₈₀B₂₀/ Ru / (Co₉₀Fe₁₀)₈₀B_{20 ,and}
B: (Co_0.95Fe_0.05)₇₅(Si_0.5B_0.5)₂₅/ Ru / (Co_0.95Fe_0.05)₇₅(Si_0.5B_0.5)_{25
Was formed.}
For comparison, as a crystalline ferromagnetic layer / non-magnetic layer / crystalline ferromagnetic layer,
C: Co₉₀Fe₁₀/ Ru / Co₉₀Fe₁₀
Was formed.
[0095]
FIG. 12 shows the relationship between the thickness of the nonmagnetic layer (Ru) and the interlayer interaction. As shown in FIG. 12, when an amorphous magnetic layer was used, the interlayer interaction was suppressed, and favorable characteristics were exhibited as the magnetic recording layer of the MRAM. In the amorphous magnetic layer, (Co₉₀Fe₁₀)₈₀B₂₀Than (Co_0.95Fe_0.05)₇₅(Si_0.5B_0.5)₂₅Shows more preferable characteristics. Also, it can be seen that if the thickness of the non-magnetic layer is 1.4 nm or more, the interlayer interaction can be extremely reduced. From this, it is expected that the switching magnetic field can be reduced.
[0096]
(Example 2)
Using various amorphous magnetic alloys, magnetoresistive elements having a structure excluding the antiferromagnetic layer from FIG. 3 were fabricated, and the dependence of the average value Hc of the switching magnetic field (coercive force) on the annealing temperature was examined.
[0097]
After forming Ta / Cu / Ta as a base electrode on a thermally oxidized Si substrate, an amorphous magnetic layer / non-magnetic layer / amorphous magnetic layer as a magnetic recording layer and AlO as a tunnel barrier layer_x, Co as a pin layer₉Fe, Ta as a cover layer, and Ta / AlCu / Ta as an upper electrode were formed. Each layer was formed by sputtering. The tunnel barrier layer was formed by oxidizing Al after sputtering. The pinned layer and the amorphous magnetic layer of the magnetic recording layer were formed in a magnetic field. Processing of the tunnel junction was performed using an excimer stepper and ion milling, and 100 devices were manufactured.
[0098]
After the device was fabricated, annealing was performed in a magnetic field at a predetermined temperature for 1 hour, and the absolute value of the switching magnetic field (average of 100 devices) was evaluated.
[0099]
FIGS. 13 to 17 show the results of the element having the magnetic recording layer having the following structure.
[0100]
Figure 13: (Co_0.90Fe_0.10)₈₅B_Fifteen(3 nm) / Ru / (Co_0.90Fe_0.10)₈₅B_Fifteen(5 nm), FIG. 13A shows Ru (1.9 nm), and FIG. 10 shows Ru (2.45 nm).
Figure 14: [(Co_0.95Fe_0.05)_0.95Nb_0.05]₈₅B_Fifteen(3 nm) / Ru / [(Co_0.95Fe_0.05)_0.95Nb_0.05]₈₅B_Fifteen(5 nm), FIG. 14A shows Ru (1.9 nm), and FIG. 14B shows Ru (2.45 nm).
Figure 15: Fe_83.5Cu₁Nb₃Si_3.5B₉(3 nm) / Ru / Fe_83.5Cu₁Nb₃Si_3.5B₉(5 nm), FIG. 15A shows Ru (1.9 nm), and FIG. 15B shows Ru (2.45 nm).
Figure 16: Fe₉₀Cu₁Zr₇B₂(3 nm) / Ru / Fe₉₀Cu₁Zr₇B₂(5 nm), FIG. 16A shows Ru (1.9 nm), and FIG. 16B shows Ru (2.45 nm).
When the Ru film thickness is 1.9 nm, weak ferromagnetic coupling occurs between the two amorphous magnetic layers, and when the Ru film thickness is 2.45 nm, it is weak between the two amorphous magnetic layers. It is considered that antiferromagnetic coupling has occurred.
[0101]
FIG. 17 shows a comparative example, in which (Co_0.90Fe_0.10)₈₀B₂₀(3 nm) This is the result of a magnetoresistive element having a single magnetic recording layer.
[0102]
From these results, when the magnetic recording layer having the structure of amorphous magnetic layer / non-magnetic layer / amorphous magnetic layer was used, the increase of the switching magnetic field was suppressed even at the annealing temperature of 400 ° C., and characteristics suitable for the MRAM were exhibited. Further, the variation (1σ) of the switching magnetic field was within 10%, and the characteristics suitable for the MRAM were exhibited.
[0103]
Further, in the ferromagnetic double tunnel junction device having the structure of FIG. 7, the variation (1σ) of the switching magnetic field was within 7%, and the characteristics more suitable for the MRAM were exhibited.
[0104]
(Example 3)
The ferromagnetic double tunnel junction device shown in FIG. 8 having a magnetic recording layer having a three-layer structure of an amorphous magnetic layer / non-magnetic layer / amorphous magnetic layer was manufactured. For comparison, a ferromagnetic double tunnel junction device having a magnetic recording layer composed of a single amorphous magnetic layer was manufactured. The bias voltage dependence of the normalized MR ratio was compared for these two devices.
[0105]
The structure of the element manufactured in this example is as follows: substrate: thermally oxidized Si substrate, base electrode: Ta (5 nm) / Cu (30 nm) / Ta (5 nm), antiferromagnetic layer: NiFe (4 nm) / IrMn (10 nm) , Pin layer: Co₉Fe (3 nm), nonmagnetic layer: Ru (1 nm), fixed layer: Co₉Fe (3 nm), tunnel barrier layer: AlO_x(1.4 nm), magnetic recording layer (free layer): Co_70.5Fe_4.7Si_FifteenB₁₀(2 nm) / Ru (1.3 nm) / Co_70.5Fe_4.7Si_FifteenB₁₀(2 nm), tunnel barrier layer: AlO_x(1.4 nm), fixed layer: Co₉Fe (3 nm), nonmagnetic layer: Ru (1 nm), pinned layer: Co₉Fe (3 nm), antiferromagnetic layer: IrMn (10 nm), cover layer: Ta, upper electrode: Ta (5 nm) / Cu (30 nm) / Ta (5 nm).
[0106]
An element fabricated for comparison has a single magnetic recording layer (free layer) of Co._70.5Fe_4.7Si_FifteenB₁₀(2 nm).
[0107]
FIGS. 18A and 18B show the bias voltage dependence of the normalized MR ratio. FIG. 18A shows the result of the comparative example, and FIG. 18B shows the result of Example 3. As can be seen from FIGS. 18A and 18B, compared with the ferromagnetic double tunnel junction device (a) having a magnetic recording layer composed of a single amorphous magnetic layer, the amorphous magnetic layer / nonmagnetic layer / amorphous The ferromagnetic double tunnel junction device (b) having a magnetic recording layer having a three-layer structure of magnetic layers has improved bias dependency of the normalized MR ratio. Therefore, it can be seen that the element of FIG. 18B obtains a large signal output and exhibits more preferable characteristics as an MRAM.
[0108]
(Example 4)
Using various amorphous magnetic alloys, magnetoresistive elements having the structure shown in FIG. 2 were fabricated, and the relationship between the element width and the switching magnetic field was examined.
[0109]
The structure of the device manufactured in this example is as follows: substrate: thermally oxidized Si substrate, base electrode: Ta / Cu / Ta, antiferromagnetic layer: Ir₂₃Mn₇₇(10 nm), pinned layer: Co₉₀Fe₁₀(3 nm), non-magnetic layer: Ru (0.9 nm), fixed layer: Co₉₀Fe₁₀(3 nm), tunnel barrier layer: AlO_x(1.2 nm), a magnetic recording layer (details will be described later), a cover layer: Ta, and an upper electrode: Ta / Cu / Ta. Each layer was formed by sputtering. The tunnel barrier layer was formed by oxidizing Al after sputtering. The pinned layer and the amorphous magnetic layer of the magnetic recording layer were formed in a magnetic field. Processing of the tunnel junction was performed using an excimer stepper and ion milling, and 100 devices were manufactured. After the device was manufactured, annealing was performed in a magnetic field at 325 ° C., and an MR curve was measured using an auto probe to perform statistical processing, and the relationship between the device width (TMR width) and the switching magnetic field was examined.
[0110]
The structure of the magnetic recording layer is as follows.
1 (Reference example): Co₂₅Fe₃₅Ni₄₀(1.8 nm) / Ru (1.7 nm) / Co₂₅Fe₃₅Ni₄₀(1.8 nm)
2: Co_70.5Fe_4.7Si_FifteenB₁₀(2 nm) / Ru (1.2 nm) / Co_70.5Fe_4.7Si_FifteenB₁₀(2 nm)
3: Co_70.5Fe_4.7Si_FifteenB₁₀(2 nm) / Ru (1.8 nm) / Co_70.5Fe_4.7Si_FifteenB₁₀(2 nm)
4: Co_70.5Fe_4.7Si_FifteenB₁₀(2 nm) / Ru (2.2 nm) / Co_70.5Fe_4.7Si_FifteenB₁₀(2 nm)
5: Fe_73.5Cu₁Nb₃Si_13.5B₉(2 nm) / Cu (2.8 nm) / Fe_73.5Cu₁Nb₃Si_13.5B₉(2 nm)
6: Co₈₇Nb₅Zr₈(2 nm) / Ir (1.2 nm) / Co₈₇Nb₅Zr₈(2 nm)
7: Co₈₄Fe₂Nb₁₄(2 nm) / Cu (2.8 nm) / Co₈₄Fe₂Nb₁₄(2 nm)
8: Fe₉₀Cu₁Zr₇B₂(2 nm) / W (2 nm) / Fe₉₀Cu₁Zr₇B₂(2 nm)
As a comparative example, X: Co of a single layer₃₅Fe₂₅Ni₄₀(2 nm), and an element having a single-layer amorphous magnetic material (Co₉₀Fe₁₀)₈₀B₂₀An element having a magnetic recording layer of (2 nm) was manufactured.
[0111]
19 and 20 show the results. As shown in these figures, when a magnetic recording layer having the structure of amorphous magnetic layer / non-magnetic layer / amorphous magnetic layer is used, the switching magnetic field has a small TMR width dependence, and the switching magnetic field has a small variation. It showed suitable characteristics. In these figures, the encircled ranges indicate specifications required for a 1 Gbit MRAM.
[0112]
Hereinafter, the architecture of the MRAM configured using the above-described magnetoresistive element will be described.
21 to 24 show an MRAM architecture using a magnetoresistive element and a MOS transistor.
[0113]
The MRAM architecture shown in FIGS. 21A and 21B will be described. A MOS transistor 30 is formed on a silicon substrate. In the insulating layer covering the MOS transistor 30, a word line (WL) 40 is provided extending in one direction. A plug and a wiring connected to the MOS transistor 30 are formed in an insulating layer covering the MOS transistor 30, and a TMR element 20 connected to the wiring is formed above the word line (WL) 40. On the TMR element 20, a bit line (BL) 50 extending in a direction orthogonal to the word line (WL) 40 is formed.
[0114]
The MRAM architecture of FIGS. 22A and 22B is the same as that of FIG. 21 except that the TMR element 20 is formed by connecting to a word line (WL) 40 and a wiring.
[0115]
The MRAM architecture of FIGS. 23A and 23B is the same as that of FIG. 21 except that a part of a word line (WL) 40 and a part of a bit line (50) are covered with magnetic films 41 and 51.
[0116]
The MRAM architecture of FIGS. 24A and 24B is the same as that of FIG. 22 except that a part of the word line (WL) 40 and the bit line (50) is covered with the magnetic films 41 and 51.
[0117]
As shown in FIGS. 23 and 24, when at least a part of the side surface of the wiring for writing to the TMR cell is covered with the soft magnetic film, the current magnetic field can be increased and the crosstalk can be reduced.
[0118]
FIG. 25 shows an MRAM architecture using a magnetoresistive element and a diode. A diode 60 and a magnetoresistive element 20 are arranged between a read / write digit line (DL) 110 extending in one direction and a read / write bit line (BL) 120 extending in a direction orthogonal to the digit line 110. Are provided. The transistor (STw) 130 is connected to the digit line (DL) 110, the transistor (STB) 140 is connected to the bit line (BL) 120, and the transistor (STw) 130 is connected to the sense amplifier (SA) 300. I have.
[0119]
FIG. 26 shows an MRAM architecture in which the magnetoresistive effect elements are arranged in a ladder shape. A write digit line (DL) 150 extending in one direction, a read bit line (BLr) 160 and a write bit line (BLw) 170 extending in a direction orthogonal to the digit line 150 are formed, and the read bit line (BLr) is formed. ) 160 and the write bit line (BLw) 170 are provided with a magnetoresistive element 20. The transistor (ST) 180 is connected to the read bit line (BLr) 160, the transistor (ST) 190 is connected to the write bit line (BLw) 170, and the transistor 180 is connected to the sense amplifier (SA) 300. .
[0120]
FIG. 27 shows an MRAM architecture in which magnetoresistive elements are arranged in a simple matrix type. A write digit line (DL) 200 and a read bit line (BLr) 210 extending in one direction are vertically arranged, and a write bit line (BLw) 220 extending in a direction orthogonal to these is formed. The magnetoresistive element 20 is provided between the line (BLr) 210 and the write bit line (BLw) 220. The transistor (ST2) 230 is connected to the read bit line (BLr) 210, the transistor (ST1) 240 is connected to the write bit line (BLw) 220, and the transistor 230 is connected to the sense amplifier (SA) 300. .
[0121]
FIG. 28 shows an MRAM architecture in which magnetoresistive elements are arranged in a simple matrix type. A write digit line (DL) 250 and a read bit line (BLr) 260 extending in one direction are arranged in parallel, and a write bit line (BLw) 270 extending in a direction orthogonal to these is formed. The magnetoresistive element 20 is provided between the line (BLr) 260 and the write bit line (BLw) 270. The transistor (ST2) 280 is connected to the read bit line (BLr) 260, the transistor (ST1) 290 is connected to the write bit line (BLw) 270, and the transistor 280 is connected to the sense amplifier (SA) 300. .
[0122]
【The invention's effect】
As described above in detail, according to the present invention, the variation of the switching magnetic field is small, the increase in the switching magnetic field can be suppressed even if the bit size of the ferromagnetic tunnel junction is reduced, and the magnetic field with excellent thermal stability and reliability can be obtained. A resistance effect element and a magnetic memory using the same can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a bottom type ferromagnetic single tunnel junction device according to an embodiment of the present invention.
FIG. 2 is a schematic view of a bottom type ferromagnetic single tunnel junction device according to an embodiment of the present invention.
FIG. 3 is a schematic diagram of a top type ferromagnetic single tunnel junction device according to an embodiment of the present invention.
FIG. 4 is a schematic view of a top type ferromagnetic single tunnel junction device according to an embodiment of the present invention.
FIG. 5 is a schematic view of a ferromagnetic double tunnel junction device according to an embodiment of the present invention.
FIG. 6 is a schematic diagram of a ferromagnetic double tunnel junction device according to an embodiment of the present invention.
FIG. 7 is a schematic diagram of a ferromagnetic double tunnel junction device according to an embodiment of the present invention.
FIG. 8 is a schematic diagram of a ferromagnetic double tunnel junction device according to an embodiment of the present invention.
FIG. 9 is a plan view of the magnetoresistive element according to the embodiment of the invention.
FIG. 10 is a schematic view of a magnetoresistive element manufactured for a heat resistance test.
FIG. 11 is a schematic view of a magnetoresistive element manufactured for a heat resistance test.
FIG. 12 is a view showing the relationship between the thickness of a nonmagnetic layer and the interlayer interaction in the magnetoresistance effect element in Example 1.
FIG. 13 is a diagram showing an absolute value of a switching magnetic field in the magnetoresistive effect element according to the second embodiment.
FIG. 14 is a diagram showing an absolute value of a switching magnetic field in the magnetoresistive effect element according to the second embodiment.
FIG. 15 is a diagram showing an absolute value of a switching magnetic field for the magnetoresistive effect element according to the second embodiment.
FIG. 16 is a diagram showing an absolute value of a switching magnetic field in the magnetoresistive element according to the second embodiment.
FIG. 17 is a diagram showing an absolute value of a switching magnetic field in a magnetoresistive element of a comparative example.
FIG. 18 is a diagram showing the bias voltage dependence of the normalized MR ratio for the magnetoresistance effect element according to the third embodiment.
FIG. 19 is a diagram showing the relationship between the element width and the switching magnetic field for the magnetoresistive element in Example 4.
FIG. 20 is a diagram showing the relationship between the element width and the switching magnetic field in the magnetoresistive effect element according to the fourth embodiment.
FIG. 21 is a diagram showing an MRAM architecture using a magnetoresistive element and a MOS transistor.
FIG. 22 is a diagram showing an MRAM architecture using a magnetoresistive element and a MOS transistor.
FIG. 23 is a diagram showing an MRAM architecture using a magnetoresistive element and a MOS transistor.
FIG. 24 is a diagram showing an MRAM architecture using a magnetoresistive element and a MOS transistor.
FIG. 25 is a diagram showing an MRAM architecture using a magnetoresistive element and a diode.
FIG. 26 is a diagram showing an MRAM architecture in which magnetoresistive elements are arranged in a ladder shape.
FIG. 27 is a diagram showing an MRAM architecture in which magnetoresistive elements are arranged in a simple matrix type.
FIG. 28 is a diagram showing an MRAM architecture in which magnetoresistive elements are arranged in a simple matrix type.
[Explanation of symbols]
1: Base electrode
2. Antiferromagnetic layer
3 ... magnetization fixed layer (pin layer)
4: Tunnel barrier layer
5 ... magnetic recording layer (free layer)
5a: Amorphous magnetic layer
5b: non-magnetic layer
5c: amorphous magnetic layer
6 ... Tunnel barrier layer
7: magnetization fixed layer (pin layer)
8 Antiferromagnetic layer
9 ... Cover layer (hard mask)
10 ... Upper electrode

Claims (8)

At least one tunnel barrier layer, a magnetic recording layer and a magnetization fixed layer provided with the tunnel barrier layer interposed therebetween, wherein the magnetic recording layer has at least two amorphous magnetic layers and a nonmagnetic layer inserted between them. A magnetoresistive element comprising a layer. The amorphous magnetic layer has the following general formula: Co-Fe-AA, Co-Fe-AA-AA2, Fe-AA-AA2, Co-AA-AA2, Co-Mn-AA-AA2, Fe-Cu-AA-AA2. , And Co-Fe-Ni-AA
(Where AA or AA2 is at least one selected from the group consisting of B, Si, Ge, Zr, Nb, P, Mo, Ta, N, C, Ti, Al, W, V, rare earth and nitrogen. Is an element of
The magnetoresistive element according to claim 1, wherein: The amorphous magnetic layer is represented by the following general formula _{(Co 1-a-b M} a T b) 100-c-d X1 c X2 d
(Where M is at least one selected from Fe, Ni and Mn, T is at least one selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and Cu, X1 is B, X2 is at least one selected from Si, Ge, C, Ga, N, F, O, Al and Sn, and 0.03 ≦ a ≦ 0.20 (where M is Ni) a is 0.03 ≦ a ≦ 0.35), 0 ≦ b ≦ 0.10, 5 ≦ c ≦ 30, 0 ≦ d ≦ 25, 15 ≦ c + d ≦ 30)
The magnetoresistive element according to claim 1, wherein: The amorphous magnetic layer, the following formula _{T 100-a-b-c} A a M b X4 c
(Where T is at least one selected from Fe, Co and Ni, A is at least one selected from Cu, Ag and Au, M is Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, X4 is at least one selected from B, Si, P, C, O, N, F, Ge, Ga, Sn, Al, Pt, and Rh.Pd; 0 ≦ a ≦ 8, 2 ≦ b ≦ 20, 2 ≦ c ≦ 35)
The magnetoresistive element according to claim 1, wherein: The amorphous magnetic layer, the following general formula _{Ni 100-a-b-c} Fe a M b X8 c
(Where M is at least one selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Cu, Ga, Ge, Sn, and X8 is B, C, N, O, At least one selected from F and P, 16 ≦ a ≦ 22, 0 ≦ b ≦ 5, 0 ≦ c ≦ 10)
The magnetoresistive element according to claim 1, wherein: The magnetoresistive element according to claim 1, wherein the nonmagnetic layer is selected from the group consisting of Ru, Cu, Ir, Cr, Ag, Au, Pt, TiW, W, TaN, and TiN. 2. The magnetoresistive element according to claim 1, wherein said nonmagnetic layer has a thickness of 1.4 nm or more. A first wiring extending in a first direction;
A second wiring provided above the first wiring and extending in a direction intersecting with the first direction;
8. A magnetic memory, comprising: the magnetoresistive element according to claim 1 provided between the first wiring and the second wiring.

Images