WO2020043020A1 - Perpendicularly magnetized mtj device - Google Patents
Perpendicularly magnetized mtj device Download PDFInfo
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- WO2020043020A1 WO2020043020A1 PCT/CN2019/102213 CN2019102213W WO2020043020A1 WO 2020043020 A1 WO2020043020 A1 WO 2020043020A1 CN 2019102213 W CN2019102213 W CN 2019102213W WO 2020043020 A1 WO2020043020 A1 WO 2020043020A1
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- the invention relates to the technical field of magnetic memory, and in particular to a vertically magnetized MTJ device.
- Vertically magnetized magnetic tunnel junction MTJ has the advantages of low write energy and scalability, and has been proven to be the most suitable magnetization configuration for developing MRAM (Magnetic Random Access Memory).
- MRAM Magnetic Random Access Memory
- This technology uses the shape anisotropy of the free layer to induce the magnetization direction of the free layer to be perpendicular to the film surface, thereby obtaining a vertically magnetized MTJ device.
- This type of MTJ device has an ultra-small diameter, and the diameter can be reduced to 10nm or smaller. In order to obtain such an ultra-small diameter MTJ device, the thickness of the free layer of a conventional MTJ structure needs to be increased.
- MTJ-based STT-MRAM requires short-term high-temperature processing during packaging, and the temperature is higher than 250 ° C. This process corresponds to large thermal disturbances. In order to avoid data loss, it is also necessary to increase the thickness of the free layer of the traditional MTJ structure.
- the STT-MRAM based on this ultra-small-diameter MTJ further increases the write current and write voltage, which increases the power consumption, which is likely to cause MTJ breakdown and reduce the number of erasable writes.
- the present invention provides a vertically magnetized MTJ device, which can reduce the write current of an STT-MRAM based on an ultra-small diameter MTJ device.
- the invention provides a vertically magnetized MTJ device, which includes a thermal stability enhancement layer, a free layer, a tunnel layer, and a fixed layer stacked in this order, wherein:
- the ratio of the thickness of the free layer to the diameter of the MTJ device is 0.75 to 2;
- the thermal stability enhancement layer has phase transition characteristics. When the temperature is lower than the phase transition temperature, the thermal stability enhancement layer is an antiferromagnetic phase. When the temperature is higher than the phase transition temperature, the thermal stability enhancement layer is ferromagnetic. phase.
- a phase transition temperature of the thermally stable enhancement layer is 50 to 250 ° C.
- the ratio of the thickness of the thermal stability enhancement layer to the diameter of the MTJ device is 0.5 to 1.3.
- the material of the thermal stability enhancement layer is FeRh, wherein Fe atoms and Rh atoms each account for 50% of the total number of atoms.
- the material of the thermal stability enhancement layer is FeRhX
- X is any one or a combination of any of Ir, Pt, V, Mn, Au, Co, and Ni, wherein the atoms occupied by Rh atoms
- the percentage of the total number is 40% to 60%, and the percentage of the total number of atoms occupied by X is 0 to 15%.
- the material of the free layer is any one of Co, Fe, Ni, CoB, FeB, NiB, CoFe, NiFe, CoNi, and CoFeB.
- the material of the tunnel layer is any one of MgO, HfO 2 , MgAlO, and AlO x (where x is 1.2 to 1.7), and the thickness of the tunnel layer is 0.4 to 1.2 nm.
- the fixed layer includes a reference magnetic layer and a synthetic antiferromagnetic pinned layer, wherein the material of the reference magnetic layer is Co, Fe, Ni, CoB, FeB, NiB, CoFe, NiFe, CoNi, and CoFeB.
- the synthetic antiferromagnetic pinned layer adopts a Co / Pt multilayer film structure or a Co / Pd multilayer film structure, and the Co / Pt multilayer film structure or the Co / Pd multilayer film structure is also It includes a coupling layer, which is located in the middle layer of the multilayer film structure.
- the material of the coupling layer is Ru, Ir or Cr.
- connection layer which is located between the free layer and the thermal stability enhancement layer, and is used to increase interlayer exchange coupling between the magnetic moment of the free layer and the magnetic moment of the thermal stability enhancement layer.
- connection layer is any one or any combination of Cu, Cr, V, Ag, Au, Mo, Ir, Ru, Pd, W, Ta, and Nd, and the connection layer The thickness is less than 0.8 nm.
- a surface of the free layer is superimposed with a thermal stability enhancement layer having phase change characteristics.
- the thermal stability enhancement layer is an antiferromagnetic phase, so that the free layer is subjected to The effect of the horizontal bias field causes part of the magnetic moment to deviate from the direction of vertical magnetization.
- the thermal stability enhancement layer is a ferromagnetic phase and forms a ferromagnetic coupling with the free layer to increase the effective thickness of the free layer.
- the write current of the STT-MRAM at a low temperature is reduced, thereby reducing the demand for the power supply capacity of the selector tube, which can reduce the size of the selector tube and enhance the thermal stability of the MTJ device at high temperatures. It guarantees the non-volatile nature of stored information and reduces read disturbances at high temperatures.
- the initial spin transfer moment STT is larger at room temperature, which also accelerates the magnetization inversion speed of the free layer.
- FIG. 1 is a schematic structural diagram of an embodiment of a vertically magnetized MTJ device according to the present invention
- FIG. 2a is a schematic diagram of the magnetization state of the MTJ device shown in FIG. 1 when the temperature is lower than the phase transition temperature of the thermal stability enhancement layer;
- 2b is a schematic diagram of the magnetization state of the MTJ device shown in FIG. 1 when the temperature is higher than the phase transition temperature of the thermal stability enhancement layer;
- FIG. 3 is a comparison effect diagram of the relationship between the reduced energy barrier height ⁇ of the vertically magnetized MTJ device of the present invention and the existing MTJ device as a function of temperature;
- FIG. 4 is a schematic structural diagram of another embodiment of a vertically magnetized MTJ device according to the present invention.
- An embodiment of the present invention provides a vertically magnetized MTJ device having an ultra-small diameter.
- the diameter D of the MTJ device is 5 to 30 nm, as shown in FIG. 1, including: a thermally stable enhancement layer 104 stacked from top to bottom; The layer 103, the tunnel layer 102, and the fixed layer 101 have the same diameter.
- the MTJ device diameter D is equal to the diameter of each layer.
- the thickness t 1 of the free layer 103 is greater than or close to the diameter D of the MTJ device. Generally, the thickness of the free layer 103 is taken.
- the ratio of t 1 to the diameter D of the MTJ device is 0.75 to 2.
- the shape anisotropy of the free layer 103 is used to induce the magnetization direction of the free layer to be perpendicular to the film surface.
- the ratio of the thickness t 2 of the thermal stability enhancement layer 104 to the diameter D of the MTJ device is 0.5 ⁇ 1.3, and the thermal stability enhancement layer 104 has phase transition characteristics.
- the thermal stability enhancement layer 104 is an antiferromagnetic phase to deflect the magnetic moment of the free layer 103.
- the thermal stability enhancement layer 104 is a ferromagnetic phase
- the free layer 103 is also a ferromagnetic phase, which is equivalent to increasing the effective thickness of the free layer.
- the vertically magnetized MTJ device of the embodiment of the present invention is to reduce the write current of the STT-MRAM based on the ultra-small diameter MTJ device by using the phase change characteristic of the thermally stable enhancement layer.
- the detailed description is as follows:
- the phase transition temperature of the thermal stability enhancement layer is denoted by T 0 , and T 0 is 50-250 ° C.
- T 0 is 50-250 ° C.
- the thermal stability enhancement layer 104 is an antiferromagnetic phase.
- the magnetic moment of the stable enhancement layer is arranged in-plane antiferromagnetic, so that an exchange bias effect occurs at the interface between the free layer 103 and the thermally stable enhancement layer 104.
- the thermal stability enhancement layer 104 is a ferromagnetic phase, and the magnetic moment of the thermal stability enhancement layer is ferromagnetic, because the magnetic moment of the thermal stability enhancement layer and the magnetic moment of the free layer exist at the interface.
- the exchange coupling causes the magnetic moment of the thermal stability enhancement layer to be arranged perpendicular to the film surface.
- the entirety of the thermal stability enhancement layer 104 and the free layer 103 can be regarded as a new free layer, which is equivalent to increasing the effective thickness of the free layer.
- the thermal stability of MTJ devices is a function of the thickness of the free layer Ratio, thus enhancing the thermal stability of the MTJ device at a high temperature.
- a core indicator of MRAM Magnetic Random Access Memory
- data retention time which depends on the height of the potential barrier between the two states in the magnetic tunnel junction MTJ. According to related theory, the data retention time of a single bit can be expressed as:
- ⁇ 0 is the characteristic time
- E is the energy barrier height
- k B is the Boltzmann constant
- T is the temperature
- ⁇ is the reduced energy barrier height
- the data retention time is defined according to the maximum ambient temperature at which the chip operates, ensuring the thermal stability of MTJ devices at high temperatures. Sex is also very necessary.
- the comparison of the relationship between the reduced energy barrier height ⁇ and the temperature is shown in FIG. 3.
- the minimum required ⁇ is 60 at 260 ° C.
- the existing MTJ device needs to have ⁇ > 122 at 0 ° C; if the MTJ device of the present invention is selected, the thickness of the thermally stable enhancement layer is 0.75 times that of the free layer, Ms (saturation magnetization) and free The layer has the same layer and the thermal stability enhancement layer has a phase transition temperature of 100 ° C.
- the vertically magnetized MTJ device reduces the write current of the STT-MRAM at a low temperature under the action of the thermal stability enhancement layer, thereby reducing the power supply capacity requirement of the selection tube and reducing the selection tube. At the same time, it enhances the thermal stability of MTJ devices at high temperatures, guarantees the non-volatile nature of stored information, and reduces read disturbances at high temperatures. In addition, the larger initial spin transfer moment STT at room temperature also accelerates the magnetization inversion speed of the free layer.
- the vertically magnetized MTJ device has great application advantages.
- each layer of the vertically magnetized MTJ device will be described in detail.
- the material for the thermal stability enhancement layer 104 may be FeRh.
- Fe atoms and Rh atoms each account for 50% of the total number of atoms
- FeRhX may also be selected.
- X is any one of Ir, Pt, V, Mn, Au, Co, and Ni. Or any combination thereof, wherein the percentage of the total number of atoms occupied by Rh atoms is 40% to 60%, and the percentage of the total number of atoms occupied by X is 0-15%.
- the material of the free layer 103 is any one of Co, Fe, Ni, CoB, FeB, NiB, CoFe, NiFe, CoNi, and CoFeB.
- a non-magnetic metal such as one of Mo, Ru, Ta, Pt, and W.
- the tunnel layer 102 serves as an insulating layer, and the material is selected from MgO, HfO 2 , MgAlO, and AlO x (where x is 1.2 to 1.7), and the thickness is 0.4 to 1.2 nm.
- the fixed layer 101 includes a reference magnetic layer and a synthetic antiferromagnetic pinned layer.
- the material of the reference magnetic layer is any one of Co, Fe, Ni, CoB, FeB, NiB, CoFe, NiFe, CoNi, and CoFeB.
- the antiferromagnetic pinned layer uses a Co / Pt multilayer film structure or a Co / Pd multilayer film structure.
- the Co / Pt multilayer film structure or Co / Pd multilayer film structure also includes a coupling layer.
- the coupling layer is located in multiple layers.
- the intermediate layer of the membrane structure, and the material of the coupling layer is Ru, Ir or Cr.
- a vertically magnetized MTJ device is a thermally stable enhancement layer, a free layer, a tunnel layer, and a fixed layer in order from top to bottom.
- the diameter of the MTJ device is 10 nm.
- the material of the thermally stable enhancement layer is Fe 0.5 Rh 0.5 , Fe atoms and Rh atoms.
- the fixed layer includes a reference magnetic layer and a synthetic antiferromagnet
- the pinned layer in which the material of the reference magnetic layer is CoFe with a thickness of 2 nm, and the structure of the synthesized antiferromagnetic pinned layer is [Pd (0.6) / Co (0.4)] 8 /Ir(0.4) / [Co ( 0.4) / Pd (0.6)] 4 multilayer film structure, the value in parentheses indicates the corresponding film thickness, the unit is nm, and the value outside the brackets, such as 8,4, indicates the number of times the structure is repeated, that is, Pd (0.6) / The Co (0.4) structure is repeated 8 times, and then a layer of Ir (0.4) is laid, and then the Co (0.4) / Pd (0.6)
- a vertically magnetized MTJ device is a thermally stable enhancement layer, a free layer, a tunnel layer, and a fixed layer in order from top to bottom.
- the diameter D of the MTJ device is 12 nm.
- the material of the thermally stable enhancement layer is Fe 0.5 Rh 0.45 Pt 0.05 , and Fe atoms account for 50% of the total number of atoms, Rh atoms 45% of the total number of atoms, Pt atoms 5% of the total number of atoms, its thickness is 10nm; the material of the free layer is CoFeB, its thickness is 16nm; the material of the tunnel layer is MgO, its thickness 0.8nm; the fixed layer includes a reference magnetic layer and a synthetic antiferromagnetic pinning layer, wherein the material of the reference magnetic layer is CoFeB, its thickness is 2nm, and the structure of the synthetic antiferromagnetic pinning layer is [Pt (0.4) / Co (0.4)] 4 /Ru(0.4)
- the MTJ device further includes a connection layer 105, which is disposed between the thermal stability enhancement layer 104 and the free layer 103.
- a connection layer 105 By connecting the layers 105, a strong interlayer exchange coupling between the magnetic moment of the free layer and the magnetic moment of the thermally stable enhancement layer can be ensured.
- the material of the connection layer 105 may be any one or a combination of any of Cu, Cr, V, Ag, Au, Mo, Ir, Ru, Pd, W, Ta, and Nd, and its thickness is less than 0.8 nm.
- the material stacking method of the MTJ device in the above embodiment adopts a stacking method of thermal stability enhancement layer, free layer, tunnel layer and fixed layer in order from top to bottom, but in actual application, according to design needs,
- the material stacking method of MTJ devices can also be reversed, that is, the stacking method of thermal stability enhancement layer, free layer, tunnel layer and fixed layer in order from bottom to top.
- This structure can also achieve the same technical effect. Here No longer.
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Abstract
A perpendicularly magnetized MTJ device, comprising: a thermal stabilization reinforcement layer (104), a free layer (103), a tunnel layer (102) and a fixation layer (101) that are subsequently stacked on top of one another, wherein the ratio of the thickness of the free layer (103) to the diameter of the MTJ device is 0.75 to 2; the thermal stabilization reinforcement layer (104) has phase transition properties, wherein the thermal stabilization reinforcement layer (104) is in an antiferromagnetic phase when the temperature is lower than a phase transition temperature and is in a ferromagnetic phase when the temperature is higher than the phase transition temperature. The present invention can reduce the write current of an STT-MRAM on the basis of an ultra-small diameter MTJ device.
Description
本发明涉及磁存储器技术领域，尤其涉及一种垂直磁化的MTJ器件。The invention relates to the technical field of magnetic memory, and in particular to a vertically magnetized MTJ device.
垂直磁化的磁隧道结MTJ具有写能量低和可微缩性的优点，已被证实为开发MRAM(Magnetic Random Access Memory，磁存储器)最合适的磁化构型。最新研究发现，自由层厚度大于MTJ半径可以用于垂直磁化MTJ，该技术利用自由层的形状各向异性诱导自由层磁化方向垂直于膜面，从而获得垂直磁化的MTJ器件。这种类型的MTJ器件具有超小直径，直径可以降低至10nm或者更小尺寸。为了得到这种超小直径MTJ器件，需要加大传统MTJ结构自由层厚度。另一方面，基于MTJ的STT-MRAM在封装时需要短暂的高温处理，温度高于250℃，这一过程对应的热扰动较大。为了避免数据丢失，也需要加大传统MTJ结构自由层厚度。Vertically magnetized magnetic tunnel junction MTJ has the advantages of low write energy and scalability, and has been proven to be the most suitable magnetization configuration for developing MRAM (Magnetic Random Access Memory). The latest research found that the thickness of the free layer greater than the MTJ radius can be used for perpendicularly magnetizing MTJ. This technology uses the shape anisotropy of the free layer to induce the magnetization direction of the free layer to be perpendicular to the film surface, thereby obtaining a vertically magnetized MTJ device. This type of MTJ device has an ultra-small diameter, and the diameter can be reduced to 10nm or smaller. In order to obtain such an ultra-small diameter MTJ device, the thickness of the free layer of a conventional MTJ structure needs to be increased. On the other hand, MTJ-based STT-MRAM requires short-term high-temperature processing during packaging, and the temperature is higher than 250 ° C. This process corresponds to large thermal disturbances. In order to avoid data loss, it is also necessary to increase the thickness of the free layer of the traditional MTJ structure.
在实现本发明的过程中，发明人发现现有技术中至少存在如下技术问题：In the process of implementing the present invention, the inventors found that at least the following technical problems exist in the prior art:
由于超小直径MTJ增加了自由层厚度，基于这种超小直径MTJ的STT-MRAM写电流及写电压进一步加大，使得功耗增加，进而容易造成MTJ击穿，可擦写次数降低。Because the ultra-small-diameter MTJ increases the thickness of the free layer, the STT-MRAM based on this ultra-small-diameter MTJ further increases the write current and write voltage, which increases the power consumption, which is likely to cause MTJ breakdown and reduce the number of erasable writes.
发明内容Summary of the Invention
为解决上述问题，本发明提供一种垂直磁化的MTJ器件，能够降低基于超小直径MTJ器件的STT-MRAM的写入电流。To solve the above problems, the present invention provides a vertically magnetized MTJ device, which can reduce the write current of an STT-MRAM based on an ultra-small diameter MTJ device.
本发明提供一种垂直磁化的MTJ器件，包括：依次叠置的热稳定增强层、自由层、隧道层以及固定层，其中，The invention provides a vertically magnetized MTJ device, which includes a thermal stability enhancement layer, a free layer, a tunnel layer, and a fixed layer stacked in this order, wherein:
所述自由层的厚度与MTJ器件直径的比值为0.75～2；The ratio of the thickness of the free layer to the diameter of the MTJ device is 0.75 to 2;
所述热稳定增强层具有相变特性，当温度低于相变温度时，所述热稳定增强层为反铁磁相，当温度高于相变温度时，所述热稳定增强层为铁磁相。The thermal stability enhancement layer has phase transition characteristics. When the temperature is lower than the phase transition temperature, the thermal stability enhancement layer is an antiferromagnetic phase. When the temperature is higher than the phase transition temperature, the thermal stability enhancement layer is ferromagnetic. phase.
可选地，所述热稳定增强层的相变温度为50～250℃。Optionally, a phase transition temperature of the thermally stable enhancement layer is 50 to 250 ° C.
可选地，所述热稳定增强层的厚度与所述MTJ器件直径的比值为0.5～1.3。Optionally, the ratio of the thickness of the thermal stability enhancement layer to the diameter of the MTJ device is 0.5 to 1.3.
可选地，所述热稳定增强层的材料为FeRh，其中，Fe原子和Rh原子各占原子总数的50％。Optionally, the material of the thermal stability enhancement layer is FeRh, wherein Fe atoms and Rh atoms each account for 50% of the total number of atoms.
可选地，所述热稳定增强层的材料为FeRhX，X为Ir、Pt、V、Mn、Au、Co、Ni中的任意一种或者任意多种的组合，其中，Rh原子所占的原子总数百分比为40％～60％，X所占的原子总数百分比为0～15％。Optionally, the material of the thermal stability enhancement layer is FeRhX, and X is any one or a combination of any of Ir, Pt, V, Mn, Au, Co, and Ni, wherein the atoms occupied by Rh atoms The percentage of the total number is 40% to 60%, and the percentage of the total number of atoms occupied by X is 0 to 15%.
可选地，所述自由层的材料为Co、Fe、Ni、CoB、FeB、NiB、CoFe、NiFe、CoNi和CoFeB中的任意一种。Optionally, the material of the free layer is any one of Co, Fe, Ni, CoB, FeB, NiB, CoFe, NiFe, CoNi, and CoFeB.
可选地，所述隧道层的材料为MgO、HfO
2、MgAlO和AlO
x(其中x为1.2～1.7)中的任意一种，所述隧道层厚度为0.4～1.2nm。
Optionally, the material of the tunnel layer is any one of MgO, HfO 2 , MgAlO, and AlO x (where x is 1.2 to 1.7), and the thickness of the tunnel layer is 0.4 to 1.2 nm.
可选地，所述固定层包括参考磁性层和合成反铁磁钉扎层，其中，所述参考磁性层的材料为Co、Fe、Ni、CoB、FeB、NiB、CoFe、NiFe、CoNi和CoFeB中的任意一种，所述合成反铁磁钉扎层采用Co/Pt多层膜结构或者Co/Pd多层膜结构，所述Co/Pt多层膜结构或者Co/Pd多层膜结构还包括一层耦合层，所述耦合层位于多层膜结构的中间层，所述耦合层的材料为Ru、Ir或者Cr。Optionally, the fixed layer includes a reference magnetic layer and a synthetic antiferromagnetic pinned layer, wherein the material of the reference magnetic layer is Co, Fe, Ni, CoB, FeB, NiB, CoFe, NiFe, CoNi, and CoFeB. In any one of the embodiments, the synthetic antiferromagnetic pinned layer adopts a Co / Pt multilayer film structure or a Co / Pd multilayer film structure, and the Co / Pt multilayer film structure or the Co / Pd multilayer film structure is also It includes a coupling layer, which is located in the middle layer of the multilayer film structure. The material of the coupling layer is Ru, Ir or Cr.
可选地，还包括：连接层，所述连接层位于所述自由层和所述热稳定增强层之间，用于增加自由层磁矩与热稳定增强层磁矩的层间交换耦合。Optionally, it further comprises: a connection layer, which is located between the free layer and the thermal stability enhancement layer, and is used to increase interlayer exchange coupling between the magnetic moment of the free layer and the magnetic moment of the thermal stability enhancement layer.
可选地，所述连接层的材料为Cu、Cr、V、Ag、Au、Mo、Ir、Ru、Pd、W、Ta和Nd中的任意一种或者任意多种的组合，所述连接层厚度小于0.8nm。Optionally, the material of the connection layer is any one or any combination of Cu, Cr, V, Ag, Au, Mo, Ir, Ru, Pd, W, Ta, and Nd, and the connection layer The thickness is less than 0.8 nm.
本发明提供的垂直磁化的MTJ器件，自由层表面叠加一层具有相变特性 的热稳定增强层，当温度低于相变温度时，热稳定增强层为反铁磁相，以使自由层受到水平偏置场作用，使得部分磁矩偏离垂直磁化方向，当温度高于相变温度时，热稳定增强层为铁磁相，与自由层形成铁磁耦合，以增加自由层的有效厚度。与现有技术相比，降低了低温下STT-MRAM的写入电流，进而降低了对选择管的供电能力需求，可降低选择管的尺寸，同时增强了MTJ器件在高温下的热稳定性，保证了存储信息的非易失性和降低了高温下的读扰动。另外，室温下初始的自旋转移矩STT较大，也加快了自由层的磁化翻转速度。In the vertically magnetized MTJ device provided by the present invention, a surface of the free layer is superimposed with a thermal stability enhancement layer having phase change characteristics. When the temperature is lower than the phase change temperature, the thermal stability enhancement layer is an antiferromagnetic phase, so that the free layer is subjected to The effect of the horizontal bias field causes part of the magnetic moment to deviate from the direction of vertical magnetization. When the temperature is higher than the phase transition temperature, the thermal stability enhancement layer is a ferromagnetic phase and forms a ferromagnetic coupling with the free layer to increase the effective thickness of the free layer. Compared with the prior art, the write current of the STT-MRAM at a low temperature is reduced, thereby reducing the demand for the power supply capacity of the selector tube, which can reduce the size of the selector tube and enhance the thermal stability of the MTJ device at high temperatures. It guarantees the non-volatile nature of stored information and reduces read disturbances at high temperatures. In addition, the initial spin transfer moment STT is larger at room temperature, which also accelerates the magnetization inversion speed of the free layer.
图1为本发明的垂直磁化的MTJ器件的一个实施例的结构示意图；1 is a schematic structural diagram of an embodiment of a vertically magnetized MTJ device according to the present invention;
图2a为图1所示MTJ器件当温度低于热稳定增强层的相变温度时的磁化状态示意图；2a is a schematic diagram of the magnetization state of the MTJ device shown in FIG. 1 when the temperature is lower than the phase transition temperature of the thermal stability enhancement layer;
图2b为图1所示MTJ器件当温度高于热稳定增强层的相变温度时的磁化状态示意图；2b is a schematic diagram of the magnetization state of the MTJ device shown in FIG. 1 when the temperature is higher than the phase transition temperature of the thermal stability enhancement layer;
图3为本发明的垂直磁化的MTJ器件与现有MTJ器件的约化后的能量势垒高度Δ随温度变化关系的对比效果图；FIG. 3 is a comparison effect diagram of the relationship between the reduced energy barrier height Δ of the vertically magnetized MTJ device of the present invention and the existing MTJ device as a function of temperature;
图4为本发明的垂直磁化的MTJ器件的另一个实施例的结构示意图。FIG. 4 is a schematic structural diagram of another embodiment of a vertically magnetized MTJ device according to the present invention.
为使本发明实施例的目的、技术方案和优点更加清楚，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments It is only a part of the embodiments of the present invention, but not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
本发明实施例提供一种垂直磁化的MTJ器件，具有超小直径，MTJ器件 直径D为5～30nm，如图1所示，包括：从上到下依次叠置的热稳定增强层104、自由层103、隧道层102以及固定层101，各层直径相同，MTJ器件直径D就等于各层直径，其中，自由层103的厚度t
1大于或者接近MTJ器件直径D，一般取自由层103的厚度t
1与MTJ器件直径D的比值为0.75～2，利用自由层103的形状各向异性诱导自由层磁化方向垂直于膜面；热稳定增强层104的厚度t
2与MTJ器件直径D的比值为0.5～1.3，同时热稳定增强层104具有相变特性，当温度低于相变温度时，热稳定增强层104为反铁磁相，以使自由层103磁矩发生偏转，当温度高于相变温度时，热稳定增强层104为铁磁相，而自由层103也是铁磁相，相当于增加自由层的有效厚度。
An embodiment of the present invention provides a vertically magnetized MTJ device having an ultra-small diameter. The diameter D of the MTJ device is 5 to 30 nm, as shown in FIG. 1, including: a thermally stable enhancement layer 104 stacked from top to bottom; The layer 103, the tunnel layer 102, and the fixed layer 101 have the same diameter. The MTJ device diameter D is equal to the diameter of each layer. The thickness t 1 of the free layer 103 is greater than or close to the diameter D of the MTJ device. Generally, the thickness of the free layer 103 is taken. The ratio of t 1 to the diameter D of the MTJ device is 0.75 to 2. The shape anisotropy of the free layer 103 is used to induce the magnetization direction of the free layer to be perpendicular to the film surface. The ratio of the thickness t 2 of the thermal stability enhancement layer 104 to the diameter D of the MTJ device is 0.5 ～ 1.3, and the thermal stability enhancement layer 104 has phase transition characteristics. When the temperature is lower than the phase transition temperature, the thermal stability enhancement layer 104 is an antiferromagnetic phase to deflect the magnetic moment of the free layer 103. When the temperature is higher than the phase When the temperature is changed, the thermal stability enhancement layer 104 is a ferromagnetic phase, and the free layer 103 is also a ferromagnetic phase, which is equivalent to increasing the effective thickness of the free layer.
本发明实施例的垂直磁化的MTJ器件就是利用热稳定增强层的相变特性来降低基于超小直径MTJ器件的STT-MRAM的写入电流。下面进行详细说明：The vertically magnetized MTJ device of the embodiment of the present invention is to reduce the write current of the STT-MRAM based on the ultra-small diameter MTJ device by using the phase change characteristic of the thermally stable enhancement layer. The detailed description is as follows:
热稳定增强层的相变温度记为T
0，T
0为50～250℃，当温度低于相变温度T
0时，如图2a所示，热稳定增强层104为反铁磁相，热稳定增强层磁矩呈面内反铁磁排布，从而自由层103与热稳定增强层104界面处会发生交换偏置效应，在交换偏置磁场的作用下，界面处的自由层磁矩会偏离垂直磁化方向，进而驱动远离界面处的自由层磁矩发生小角度偏转，因此初始的自旋转移矩STT增大，翻转电流降低，即降低了STT-MRAM的写入电流；当温度超过相变温度T
0时，如图2b所示，热稳定增强层104为铁磁相，热稳定增强层磁矩呈铁磁排布，因为热稳定增强层磁矩与自由层磁矩在界面处存在交换耦合，导致热稳定增强层磁矩会垂直于膜面排布，此时热稳定增强层104与自由层103的整体可视为一个新的自由层，相当于增大了自由层的有效厚度，而MTJ器件的热稳定性与自由层厚度成正比，因此高温下该MTJ器件的热稳定性增强。
The phase transition temperature of the thermal stability enhancement layer is denoted by T 0 , and T 0 is 50-250 ° C. When the temperature is lower than the phase transition temperature T 0 , as shown in FIG. 2 a, the thermal stability enhancement layer 104 is an antiferromagnetic phase. The magnetic moment of the stable enhancement layer is arranged in-plane antiferromagnetic, so that an exchange bias effect occurs at the interface between the free layer 103 and the thermally stable enhancement layer 104. Under the action of the exchange bias magnetic field, the free layer magnetic moment at the interface will Deviate from the perpendicular magnetization direction, and then drive the magnetic moment of the free layer away from the interface to deflection at a small angle, so the initial spin transfer moment STT increases and the flip current decreases, which reduces the write current of STT-MRAM; when the temperature exceeds the phase When the temperature T 0 is changed, as shown in FIG. 2b, the thermal stability enhancement layer 104 is a ferromagnetic phase, and the magnetic moment of the thermal stability enhancement layer is ferromagnetic, because the magnetic moment of the thermal stability enhancement layer and the magnetic moment of the free layer exist at the interface. The exchange coupling causes the magnetic moment of the thermal stability enhancement layer to be arranged perpendicular to the film surface. At this time, the entirety of the thermal stability enhancement layer 104 and the free layer 103 can be regarded as a new free layer, which is equivalent to increasing the effective thickness of the free layer. And the thermal stability of MTJ devices is a function of the thickness of the free layer Ratio, thus enhancing the thermal stability of the MTJ device at a high temperature.
补充说明的是，作为非易失性存储器，MRAM(Magnetic Random Access Memory，磁存储器)的一个核心指标是数据保持时间，其取决于磁隧道结MTJ中两态之间的势垒高度。依据相关理论，单个位(bit)的数据保持时间可以表达为：It is added that as a non-volatile memory, a core indicator of MRAM (Magnetic Random Access Memory) is data retention time, which depends on the height of the potential barrier between the two states in the magnetic tunnel junction MTJ. According to related theory, the data retention time of a single bit can be expressed as:
τ＝τ
0expΔ＝τ
0exp(E/k
BT)
τ = τ 0 expΔ = τ 0 exp (E / k B T)
其中，τ
0为特征时间，E为能量势垒高度，k
B为玻尔兹曼常数，T为温度，Δ为约化后的能量势垒高度。
Among them, τ 0 is the characteristic time, E is the energy barrier height, k B is the Boltzmann constant, T is the temperature, and Δ is the reduced energy barrier height.
可见，随着温度升高，约化后的能量势垒高度Δ会降低，热稳定性降低，因此数据保持时间是按照芯片工作的最高环境温度来定义的，保证MTJ器件在高温下的热稳定性也是十分必要的。It can be seen that as the temperature increases, the reduced energy barrier height Δ will decrease and the thermal stability will decrease. Therefore, the data retention time is defined according to the maximum ambient temperature at which the chip operates, ensuring the thermal stability of MTJ devices at high temperatures. Sex is also very necessary.
对比本发明的垂直磁化的MTJ器件与现有MTJ器件，约化后的能量势垒高度Δ随温度变化关系的对比效果图如图3所示，图3中以260℃时对应Δ最低要求60为例，为了达到此项指标，现有MTJ器件需要在0℃时具备Δ>122；本发明的MTJ器件，如果选取热稳定增强层厚度为自由层0.75倍，Ms(饱和磁化强度)与自由层一致，热稳定增强层相变温度100℃，由于在该相变温度存在热稳定因子突然增大，本发明对应的0℃热稳定因子可优化为Δ＝83。由于在两种结构中0℃下的热稳定因子全部由自由层提供，本发明需要的自由层厚度仅为现有MTJ器件自由层厚度的2/3左右。写电流大小大致正比于自由层厚度，且本发明还可以使得自由层磁矩发生小角度偏转，因此两个因素共同作用下可以大幅降低写电流。Comparing the vertically magnetized MTJ device of the present invention with the existing MTJ device, the comparison of the relationship between the reduced energy barrier height Δ and the temperature is shown in FIG. 3. In FIG. 3, the minimum required Δ is 60 at 260 ° C. For example, in order to achieve this index, the existing MTJ device needs to have Δ> 122 at 0 ° C; if the MTJ device of the present invention is selected, the thickness of the thermally stable enhancement layer is 0.75 times that of the free layer, Ms (saturation magnetization) and free The layer has the same layer and the thermal stability enhancement layer has a phase transition temperature of 100 ° C. Due to the sudden increase in the thermal stability factor at this phase transition temperature, the 0 ° C thermal stability factor corresponding to the present invention can be optimized to Δ = 83. Since the thermal stability factors at 0 ° C in both structures are all provided by the free layer, the thickness of the free layer required by the present invention is only about 2/3 of the thickness of the free layer of the existing MTJ device. The magnitude of the write current is approximately proportional to the thickness of the free layer, and the invention can also cause a small angle deflection of the magnetic moment of the free layer, so the write current can be greatly reduced by the combination of two factors.
通过上述分析可知，本发明实施例的垂直磁化的MTJ器件在热稳定增强层作用下，降低了低温下STT-MRAM的写入电流，进而降低了对选择管的供电能力需求，可降低选择管的尺寸，同时增强了MTJ器件在高温下的热稳定性，保证了存储信息的非易失性和降低了高温下的读扰动。另外，室温下初始 的自旋转移矩STT较大，也加快了自由层的磁化翻转速度。本发明实施例的垂直磁化的MTJ器件具有很大的应用优势。It can be known from the above analysis that the vertically magnetized MTJ device according to the embodiment of the present invention reduces the write current of the STT-MRAM at a low temperature under the action of the thermal stability enhancement layer, thereby reducing the power supply capacity requirement of the selection tube and reducing the selection tube. At the same time, it enhances the thermal stability of MTJ devices at high temperatures, guarantees the non-volatile nature of stored information, and reduces read disturbances at high temperatures. In addition, the larger initial spin transfer moment STT at room temperature also accelerates the magnetization inversion speed of the free layer. The vertically magnetized MTJ device according to the embodiment of the present invention has great application advantages.
进一步地，基于图1，对垂直磁化的MTJ器件各层的材料和厚度作详细介绍。Further, based on FIG. 1, the material and thickness of each layer of the vertically magnetized MTJ device will be described in detail.
热稳定增强层104的材料可以选择FeRh，其中，Fe原子和Rh原子各占原子总数的50％，也可以选择FeRhX，X为Ir、Pt、V、Mn、Au、Co、Ni中的任意一种或者任意多种的组合，其中，Rh原子所占的原子总数百分比为40％～60％，X所占的原子总数百分比为0～15％。The material for the thermal stability enhancement layer 104 may be FeRh. Among them, Fe atoms and Rh atoms each account for 50% of the total number of atoms, and FeRhX may also be selected. X is any one of Ir, Pt, V, Mn, Au, Co, and Ni. Or any combination thereof, wherein the percentage of the total number of atoms occupied by Rh atoms is 40% to 60%, and the percentage of the total number of atoms occupied by X is 0-15%.
自由层103的材料为Co、Fe、Ni、CoB、FeB、NiB、CoFe、NiFe、CoNi和CoFeB中的任意一种，可选地，自由层中有1个或多个***层，***层材料为非磁性金属，如Mo,Ru,Ta,Pt,W中的一种。The material of the free layer 103 is any one of Co, Fe, Ni, CoB, FeB, NiB, CoFe, NiFe, CoNi, and CoFeB. Optionally, there are one or more intervening layers in the free layer. It is a non-magnetic metal, such as one of Mo, Ru, Ta, Pt, and W.
隧道层102作为绝缘层，材料从MgO、HfO
2、MgAlO和AlO
x(其中x为1.2～1.7)中选择任意一种，其厚度为0.4～1.2nm。
The tunnel layer 102 serves as an insulating layer, and the material is selected from MgO, HfO 2 , MgAlO, and AlO x (where x is 1.2 to 1.7), and the thickness is 0.4 to 1.2 nm.
固定层101包括参考磁性层和合成反铁磁钉扎层，其中，参考磁性层的材料为Co、Fe、Ni、CoB、FeB、NiB、CoFe、NiFe、CoNi和CoFeB中的任意一种，合成反铁磁钉扎层采用Co/Pt多层膜结构或者Co/Pd多层膜结构，Co/Pt多层膜结构或者Co/Pd多层膜结构还包括一层耦合层，耦合层位于多层膜结构的中间层，耦合层的材料为Ru、Ir或者Cr。The fixed layer 101 includes a reference magnetic layer and a synthetic antiferromagnetic pinned layer. The material of the reference magnetic layer is any one of Co, Fe, Ni, CoB, FeB, NiB, CoFe, NiFe, CoNi, and CoFeB. The antiferromagnetic pinned layer uses a Co / Pt multilayer film structure or a Co / Pd multilayer film structure. The Co / Pt multilayer film structure or Co / Pd multilayer film structure also includes a coupling layer. The coupling layer is located in multiple layers. The intermediate layer of the membrane structure, and the material of the coupling layer is Ru, Ir or Cr.
为了更加清楚直观，列举本发明的垂直磁化的MTJ器件的两个具体结构示例，说明各层的材料和厚度。In order to be more clear and intuitive, two specific structural examples of the vertically magnetized MTJ device of the present invention are listed, and the materials and thicknesses of the layers are described.
示例一：Example one:
垂直磁化的MTJ器件，从上到下依次为热稳定增强层、自由层、隧道层以及固定层，MTJ器件直径D为10nm，热稳定增强层的材料为Fe
0.5Rh
0.5，Fe 原子和Rh原子各占原子总数的50％，其厚度为9nm；自由层的材料为FeB，其厚度为14nm；隧道层的材料为HfO
2，其厚度为0.6nm；固定层包括参考磁性层和合成反铁磁钉扎层，其中，参考磁性层的材料为CoFe，其厚度为2nm，合成反铁磁钉扎层的结构为[Pd(0.6)/Co(0.4)]
8/Ir(0.4)/[Co(0.4)/Pd(0.6)]
4多层膜结构，小括号内数值表示相应薄膜厚度，单位为nm，中括号外数值，如8,4，表示该结构重复的次数，即Pd(0.6)/Co(0.4)结构重复8次，再铺一层Ir(0.4)，接着Co(0.4)/Pd(0.6)结构重复4次，其中Ir(0.4)为耦合层。
A vertically magnetized MTJ device is a thermally stable enhancement layer, a free layer, a tunnel layer, and a fixed layer in order from top to bottom. The diameter of the MTJ device is 10 nm. The material of the thermally stable enhancement layer is Fe 0.5 Rh 0.5 , Fe atoms and Rh atoms. Each accounts for 50% of the total number of atoms, its thickness is 9nm; the material of the free layer is FeB, its thickness is 14nm; the material of the tunnel layer is HfO 2 , its thickness is 0.6nm; the fixed layer includes a reference magnetic layer and a synthetic antiferromagnet The pinned layer, in which the material of the reference magnetic layer is CoFe with a thickness of 2 nm, and the structure of the synthesized antiferromagnetic pinned layer is [Pd (0.6) / Co (0.4)] 8 /Ir(0.4) / [Co ( 0.4) / Pd (0.6)] 4 multilayer film structure, the value in parentheses indicates the corresponding film thickness, the unit is nm, and the value outside the brackets, such as 8,4, indicates the number of times the structure is repeated, that is, Pd (0.6) / The Co (0.4) structure is repeated 8 times, and then a layer of Ir (0.4) is laid, and then the Co (0.4) / Pd (0.6) structure is repeated 4 times, where Ir (0.4) is a coupling layer.
示例二：Example two:
垂直磁化的MTJ器件，从上到下依次为热稳定增强层、自由层、隧道层以及固定层，MTJ器件直径D为12nm，热稳定增强层的材料为Fe
0.5Rh
0.45Pt
0.05，Fe原子占原子总数的50％，Rh原子占原子总数的45％，Pt原子占原子总数的5％，其厚度为10nm；自由层的材料为CoFeB，其厚度为16nm；隧道层的材料为MgO，其厚度为0.8nm；固定层包括参考磁性层和合成反铁磁钉扎层，其中，参考磁性层的材料为CoFeB，其厚度为2nm，合成反铁磁钉扎层的结构为[Pt(0.4)/Co(0.4)]
4/Ru(0.4)/[Co(0.4)/Pt(0.4)]
2多层膜结构，小括号内数值表示相应薄膜厚度，单位为nm，中括号外数值，如4,2，表示该结构重复的次数，即Pt(0.4)/Co(0.4)结构重复4次，再铺一层Ru(0.4)，接着Co(0.4)/Pt(0.4)结构重复2次，其中Ru(0.4)为耦合层。
A vertically magnetized MTJ device is a thermally stable enhancement layer, a free layer, a tunnel layer, and a fixed layer in order from top to bottom. The diameter D of the MTJ device is 12 nm. The material of the thermally stable enhancement layer is Fe 0.5 Rh 0.45 Pt 0.05 , and Fe atoms account for 50% of the total number of atoms, Rh atoms 45% of the total number of atoms, Pt atoms 5% of the total number of atoms, its thickness is 10nm; the material of the free layer is CoFeB, its thickness is 16nm; the material of the tunnel layer is MgO, its thickness 0.8nm; the fixed layer includes a reference magnetic layer and a synthetic antiferromagnetic pinning layer, wherein the material of the reference magnetic layer is CoFeB, its thickness is 2nm, and the structure of the synthetic antiferromagnetic pinning layer is [Pt (0.4) / Co (0.4)] 4 /Ru(0.4)/[Co(0.4)/Pt(0.4)] 2 Multi-layer film structure, the value in parentheses indicates the corresponding film thickness, the unit is nm, the value outside the brackets, such as 4, 2, the number of times the structure is repeated, that is, the Pt (0.4) / Co (0.4) structure is repeated 4 times, and then a layer of Ru (0.4) is laid, and then the Co (0.4) / Pt (0.4) structure is repeated 2 times, in which Ru (0.4) is a coupling layer.
可选地，在图1所示垂直磁化的MTJ器件结构示意图的基础上，如图4所示，MTJ器件还包括：连接层105，连接层105设置在热稳定增强层104和自由层103之间，通过连接层105，可以保证自由层磁矩与热稳定增强层磁矩发生较强的层间交换耦合。连接层105的材料可以为Cu、Cr、V、Ag、Au、Mo、Ir、Ru、Pd、W、Ta和Nd中的任意一种或者任意多种的组合，其厚度 小于0.8nm。Optionally, based on the structure of the vertically magnetized MTJ device shown in FIG. 1, as shown in FIG. 4, the MTJ device further includes a connection layer 105, which is disposed between the thermal stability enhancement layer 104 and the free layer 103. By connecting the layers 105, a strong interlayer exchange coupling between the magnetic moment of the free layer and the magnetic moment of the thermally stable enhancement layer can be ensured. The material of the connection layer 105 may be any one or a combination of any of Cu, Cr, V, Ag, Au, Mo, Ir, Ru, Pd, W, Ta, and Nd, and its thickness is less than 0.8 nm.
另外需要说明的是，上述实施例中的MTJ器件的材料堆叠方式采用从上到下依次为热稳定增强层、自由层、隧道层和固定层的堆叠方式，但是实际应用时，根据设计需要，MTJ器件的材料堆叠方式还可以反转过来，即采用从下到上依次为热稳定增强层、自由层、隧道层和固定层的堆叠方式，这种结构也可以取得同样的技术效果，在此不再赘述。In addition, it should be noted that the material stacking method of the MTJ device in the above embodiment adopts a stacking method of thermal stability enhancement layer, free layer, tunnel layer and fixed layer in order from top to bottom, but in actual application, according to design needs, The material stacking method of MTJ devices can also be reversed, that is, the stacking method of thermal stability enhancement layer, free layer, tunnel layer and fixed layer in order from bottom to top. This structure can also achieve the same technical effect. Here No longer.
以上所述，仅为本发明的具体实施方式，但本发明的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，可轻易想到的变化或替换，都应涵盖在本发明的保护范围之内。因此，本发明的保护范围应该以权利要求的保护范围为准。The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present invention. All should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
- 一种垂直磁化的MTJ器件，其特征在于，包括：依次叠置的热稳定增强层、自由层、隧道层以及固定层，其中，A vertically magnetized MTJ device, characterized in that it includes: a thermal stability enhancement layer, a free layer, a tunnel layer, and a fixed layer which are sequentially stacked, wherein,所述自由层的厚度与MTJ器件直径的比值为0.75～2；The ratio of the thickness of the free layer to the diameter of the MTJ device is 0.75 to 2;所述热稳定增强层具有相变特性，当温度低于相变温度时，所述热稳定增强层为反铁磁相，当温度高于相变温度时，所述热稳定增强层为铁磁相。The thermal stability enhancement layer has phase transition characteristics. When the temperature is lower than the phase transition temperature, the thermal stability enhancement layer is an antiferromagnetic phase. When the temperature is higher than the phase transition temperature, the thermal stability enhancement layer is ferromagnetic. phase.
- 根据权利要求1所述的垂直磁化的MTJ器件，其特征在于，所述热稳定增强层的相变温度为50～250℃。The MTJ device of claim 1, wherein a phase transition temperature of the thermally stable enhancement layer is 50 to 250 ° C.
- 根据权利要求1所述的垂直磁化的MTJ器件，其特征在于，所述热稳定增强层的厚度与所述MTJ器件直径的比值为0.5～1.3。The vertically magnetized MTJ device according to claim 1, wherein a ratio of a thickness of the thermally stable enhancement layer to a diameter of the MTJ device is 0.5 to 1.3.
- 根据权利要求1所述的垂直磁化的MTJ器件，所述热稳定增强层的材料为FeRh，其中，Fe原子和Rh原子各占原子总数的50％。The perpendicularly magnetized MTJ device according to claim 1, wherein the material of the thermal stability enhancement layer is FeRh, wherein Fe atoms and Rh atoms each account for 50% of the total number of atoms.
- 根据权利要求1所述的垂直磁化的MTJ器件，所述热稳定增强层的材料为FeRhX，X为Ir、Pt、V、Mn、Au、Co、Ni中的任意一种或者任意多种的组合，其中，Rh原子所占的原子总数百分比为40％～60％，X所占的原子总数百分比为0～15％。The vertically magnetized MTJ device according to claim 1, wherein the material of the thermally stable enhancement layer is FeRhX, and X is any one or any combination of Ir, Pt, V, Mn, Au, Co, and Ni Among them, the percentage of total atoms occupied by Rh atoms is 40% to 60%, and the percentage of total atoms occupied by X is 0-15%.
- 根据权利要求1所述的垂直磁化的MTJ器件，其特征在于，所述自由层的材料为Co、Fe、Ni、CoB、FeB、NiB、CoFe、NiFe、CoNi和CoFeB中的任意一种。The MTJ device of claim 1, wherein a material of the free layer is any one of Co, Fe, Ni, CoB, FeB, NiB, CoFe, NiFe, CoNi, and CoFeB.
- 根据权利要求1所述的垂直磁化的MTJ器件，其特征在于，所述隧道层的材料为MgO、HfO 2、MgAlO和AlO x(其中x为1.2～1.7)中的任意一种，所述隧道层厚度为0.4～1.2nm。 The perpendicular magnetization of the MTJ device as claimed in claim 1, wherein said material is a layer 2 tunnel, and MgAlO any one of an AlO x (where x is 1.2 ~ 1.7) MgO, HfO, the tunnel The layer thickness is 0.4 to 1.2 nm.
- 根据权利要求1所述的垂直磁化的MTJ器件，其特征在于，所述固定层包括参考磁性层和合成反铁磁钉扎层，其中，所述参考磁性层的材料为Co、Fe、Ni、CoB、FeB、NiB、CoFe、NiFe、CoNi和CoFeB中的任意一种，所述合成反铁磁钉扎层采用Co/Pt多层膜结构或者Co/Pd多层膜结构，所述Co/Pt多层膜结构或者Co/Pd多层膜结构还包括一层耦合层，所述耦合层位于多层膜结构的中间层，所述耦合层的材料为Ru、Ir或者Cr。The MTJ device according to claim 1, wherein the fixed layer comprises a reference magnetic layer and a synthetic antiferromagnetic pinned layer, wherein the material of the reference magnetic layer is Co, Fe, Ni, Any one of CoB, FeB, NiB, CoFe, NiFe, CoNi, and CoFeB, the synthetic antiferromagnetic pinned layer adopts a Co / Pt multilayer film structure or a Co / Pd multilayer film structure, and the Co / Pt The multilayer film structure or the Co / Pd multilayer film structure further includes a coupling layer, the coupling layer is located in an intermediate layer of the multilayer film structure, and the material of the coupling layer is Ru, Ir, or Cr.
- 根据权利要求1至8中任一项所述的垂直磁化的MTJ器件，其特征在于，还包括：连接层，所述连接层位于所述自由层和所述热稳定增强层之间，用于增加自由层磁矩与热稳定增强层磁矩的层间交换耦合。The vertically magnetized MTJ device according to any one of claims 1 to 8, further comprising: a connection layer, the connection layer being located between the free layer and the thermal stability enhancement layer, for Interlayer exchange coupling of increasing the magnetic moment of the free layer and the magnetic moment of the thermally stable enhancement layer.
- 根据权利要求9所述的垂直磁化的MTJ器件，其特征在于，所述连接层的材料为Cu、Cr、V、Ag、Au、Mo、Ir、Ru、Pd、W、Ta和Nd中的任意一种或者任意多种的组合，所述连接层厚度小于0.8nm。The MTJ device of claim 9, wherein the material of the connection layer is any one of Cu, Cr, V, Ag, Au, Mo, Ir, Ru, Pd, W, Ta, and Nd One or any combination thereof, the thickness of the connection layer is less than 0.8 nm.
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