WO2018227901A1

WO2018227901A1 - Vertically magnetized mtj device and stt-mram

Info

Publication number: WO2018227901A1
Application number: PCT/CN2017/114961
Authority: WO
Inventors: 简红; 蒋信
Original assignee: 中电海康集团有限公司
Priority date: 2017-06-14
Filing date: 2017-12-07
Publication date: 2018-12-20
Also published as: CN109087995A; CN109087995B

Abstract

A vertically magnetized MTJ device and an STT-MRAM. The vertically magnetized MTJ device comprises a reference layer (2), an insulation barrier layer (3), a free layer (4), an enhancing layer (5), a demagnetization coupling layer (6) and a fixed layer (7) that are stacked in sequence. The magnetization direction of the reference layer (2) is opposite to that of the fixed layer (7). The enhancing layer (5) is used for enhancing the vertical magnetic anisotropy of the free layer (4). The demagnetization coupling layer (6) is used for isolating the free layer (4) from the fixed layer (7). The device reduces a critical write current, reduces the energy consumption of an STT-MRAM chip, and also increases the write speed of data. The fixed layer (7) can offset the stray magnetic field applied by the reference layer (2) to the free layer (4), so as to avoid the mutual interference among different bits. In addition, the enhancing layer (5) in the vertically magnetized MTJ device can enhance the magnetic anisotropy of the free layer (4), thereby increasing the thermal stability of the free layer (4).

Description

Vertical magnetization MTJ device and STT-MRAM

Technical field

The present application relates to the field of computer storage technology, and in particular to a perpendicular magnetization MTJ device and an STT-MRAM.

Background technique

Spin Transfer Torque Magnetic Random Access Memory (STT-MRAM) is a new type of nonvolatile memory whose core memory unit is an MTJ device. The MTJ is mainly composed of a reference layer, an insulating barrier layer, and a free layer. The reference layer, also known as the pinning layer, maintains its magnetization direction unchanged, changing only the magnetization direction of the free layer to be in the same or opposite direction as the reference layer.

The MTJ device relies on quantum tunneling effects to pass electrons through the insulating barrier layer. The tunneling probability of the polarized electrons and the reference layer are related to the relative magnetization direction of the free layer. When the magnetization direction of the free layer and the reference layer are the same, the tunneling probability of the polarized electrons is high. At this time, the MTJ device exhibits a low resistance state (Rp); and when the free layer and the reference layer have opposite magnetization directions, the polarization The electron tunneling probability is low. At this time, the MTJ device exhibits a high resistance state (Rap). The MRAM uses the Rp state and the Rap state of the MTJ device to represent the logic states "1" and "0", respectively, thereby realizing data storage. The tunneling magnetoresistance value is expressed as: TMR = 100% × (R _{ap -} R _p ) / R _p .

Unlike traditional MRAM, STT-MRAM uses the current's spin transfer torque effect (STT) to write to the MRAM. When the spin-polarized current passes through a magnetic film, the polarization current will be local to the magnetic film. An exchange interaction occurs, which applies a moment to the local magnetic moment of the magnetic film, which tends to be the same as the polarization direction of the spin-polarized current. This phenomenon is called the spin transfer torque effect (STT effect). A magnetic field is applied to the magnetic film in a direction opposite to the magnetization direction. When the intensity of the polarization current exceeds a certain threshold, the magnetic moment of the magnetic film itself can be reversed. The spin transfer torque effect can be used to make the magnetization direction of the free layer of the MTJ device parallel or anti-parallel to the magnetization direction of the reference layer, thereby achieving a "write" operation.

In the prior art, the MTJ structure for the STT-MRAM can be classified into two types: one is an in-plane magnetization MTJ (i-MTJ), and the magnetization directions of the reference layer and the free layer are located in the plane of the film. The other is a perpendicular magnetization MTJ (p-MTJ) in which the magnetization directions of the reference layer and the free layer are both perpendicular to the film plane (i.e., the thick direction of each layer). The perpendicular magnetization MTJ utilizes perpendicular magnetic anisotropy such that the easy axis of the film is perpendicular to the interface. The perpendicular magnetization MTJ can further reduce the MTJ bit size compared with the in-plane magnetization MTJ, thereby achieving a higher storage density, and the criticality required for the magnetization direction perpendicular to the interface MTJ compared to the in-plane MTJ. The flip current is smaller.

At present, the critical write current of the perpendicular magnetization MTJ device (the critical current that causes the free layer to flip) is high, which is not conducive to further reduction of energy consumption and storage density of the STT-MRAM chip.

Summary of the invention

The main purpose of the present application is to provide a perpendicular magnetization MTJ device and an STT-MRAM to solve the prior art The problem of high critical write current of a directly magnetized MTJ device.

In order to achieve the above object, according to an aspect of the present application, a perpendicular magnetization MTJ device including a reference layer, an insulating barrier layer, a free layer, a reinforcement layer, and a demagnetization coupling layer which are sequentially disposed are sequentially provided. And a fixed layer, wherein the reference layer is opposite to a magnetization direction of the fixed layer, the reinforcing layer is for enhancing perpendicular magnetic anisotropy of the free layer, and the demagnetization coupling layer is for isolating the free layer from the fixed layer.

Further, the coercive force of the reference layer and the fixed layer is H _c1 and H _c2 , wherein H _c1 >H _c2 .

Further, the coercive force of the reference layer and the fixed layer is H _c1 and H _c2 , wherein H _c2 >H _c1 .

Further, the reference layer and the fixed layer respectively comprise a plurality of magnetic layers, and the magnetic layer having the smallest distance from the insulating barrier layer in the reference layer is a reference magnetic layer, and the distance between the fixed layer and the demagnetization coupling layer is the smallest The magnetic layer is a fixed magnetic layer, and the reference magnetic layer is opposite to the magnetization direction of the fixed magnetic layer.

Further, the material of the reference layer is selected from the group consisting of Co, Ni, Fe, CoFe, CoNi, NiFe, CoFeNi, CoB, FeB, CoFeB, NiFeB, Pt, Pd, PtPd, FePt, Ir, Ru, Re, Rh, B, One or more of Zr, V, Nb, Ta, Mo, W, Cu, Ag, Au, Al, and Hf.

Further, the material of the insulating barrier layer is selected from the group consisting of a magnesium oxide compound, a silicon oxide compound, a silicon nitride compound, an aluminum oxide compound, a magnesium aluminum oxide compound, a titanium oxide compound layer, a silicon oxide compound, a calcium oxide compound and a ferrite compound. Preferably, the thickness of the insulating barrier layer is between 0.5 and 20 nm.

Further, the material of the free layer is selected from the group consisting of Co, Fe, Ni, Pt, Pd, Ru, Ta, Cu, CoB, FeB, NiB, CoFe, NiFe, CoNi, CoFeNi, CoFeB, NiFeB, CoNiB, CoFeNiB, FePt, One or more of FePd, CoPt, CoPd, CoFePt, CoFePd, FePtPd, CoPtPd and CoFePtPd.

Further, the material of the above reinforcing layer is selected from one or more of Ag, Au, Pt, Pd, Rh, Ru, Re, Mo, Hf, Ir, Ni, Nb, W and V, preferably the above reinforcing layer The thickness is between 0.2 and 1 nm.

Further, the material of the demagnetization coupling layer is selected from one or more of Cu, Al, Cr, Ta, Zr, TaN and TiN, and preferably the thickness of the demagnetization coupling layer is between 0.5 and 10 nm.

Further, the material of the above fixed layer is selected from the group consisting of Co, Ni, Fe, CoFe, CoNi, NiFe, CoFeNi, CoB, FeB, CoFeB, NiFeB, Pt, Pd, PtPd, FePt, Ir, Ru, Re, Rh, B, One or more of Zr, V, Nb, Ta, Mo, W, Cu, Ag, Au, Al, and Hf.

Further, the perpendicular magnetization MTJ device further includes: a first electrode layer disposed on a surface of the reference layer away from the insulating barrier layer; and a second electrode layer disposed on the fixed layer away from the demagnetization coupling layer On the surface.

In accordance with another aspect of the present application, an STT-MRAM is provided comprising a perpendicular magnetization MTJ device, any of the above described perpendicular magnetization MTJ devices.

Applying the technical solution of the present application, the perpendicular magnetization MTJ device in the process of writing data by using the spin transfer torque effect, the electron flowing from the fixed layer to the free layer or from the free layer to the fixed layer applies a moment to the free layer, MTJ device The component applies a positive bias voltage so that electrons flow from the fixed layer to the reference layer. After passing through the fixed layer, the electrons polarized by the fixed layer apply a moment to the free layer, so that the magnetization direction of the free layer is the same as the magnetization direction of the fixed layer. On the other hand, in the process of electron flow from the free layer to the reference layer, due to the spin filtering effect of the reference layer, the polarized electrons reflected from the reference layer back to the free layer apply a moment to the free layer, so that the free layer magnetization direction Contrary to the magnetization direction of the reference layer, since the reference layer and the fixed layer are magnetized in opposite directions, the reference layer and the fixed layer have the same direction of the moment applied to the free layer.

Applying a reverse bias voltage to the MTJ device, so that electrons flow from the reference layer to the fixed layer. After passing through the reference layer, the electrons polarized by the reference layer apply a moment to the free layer, so that the free layer magnetization direction and the reference layer are magnetized. The direction is the same. On the other hand, in the process of electron flow from the free layer to the fixed layer, due to the spin filtering effect of the fixed layer, the polarized electrons reflected from the fixed layer back to the free layer also exert a moment on the free layer, making it free. The magnetization direction of the layer is opposite to the magnetization direction of the fixed layer. Since the magnetization directions of the reference layer and the fixed layer are opposite, the direction of the moment applied by the reference layer and the fixed layer to the free layer is uniform.

In summary, the direction of the moment of the fixed layer to the free layer is the same as the direction of the reference layer to the free layer, which makes the free layer more likely to be flipped, thereby reducing the critical write current and reducing the energy consumption of the STT-MRAM chip. At the same time, the writing rate of the data is also improved, and the fixed layer can cancel the scattered magnetic field of the reference layer acting on the free layer to avoid mutual interference between different bits; in addition, the enhancement layer in the above perpendicular magnetization MTJ device can The magnetic anisotropy of the free layer is enhanced, thereby increasing the thermal stability of the free layer.

DRAWINGS

The accompanying drawings, which are incorporated in the claims of the claims In the drawing:

1 shows a schematic structural view of a perpendicular magnetization MTJ device provided in accordance with an exemplary embodiment of the present application;

FIG. 2 is a schematic structural view of a perpendicular magnetization MTJ device provided by another embodiment of the present application.

Wherein, the above figures include the following reference numerals:

1, a first electrode layer; 2, a reference layer; 3, an insulating barrier layer; 4, a free layer; 5, a reinforcing layer; 6, a demagnetization coupling layer; 7, a fixed layer; 8, a second electrode layer.

detailed description

It should be noted that the following detailed description is illustrative and is intended to provide a further description of the application. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise indicated.

It is to be noted that the terminology used herein is for the purpose of describing particular embodiments, and is not intended to limit the exemplary embodiments. As used herein, the singular forms are also intended unless the context clearly dictates otherwise In addition, the terms "comprises" and "includes", when used in the specification, are intended to indicate the presence of features, steps, operations, devices, components, and/or combinations thereof.

As described in the background art, the critical write current of the prior art perpendicular magnetization MTJ device is relatively high. To solve the above technical problem, the present application proposes a perpendicular magnetization MTJ device and an STT-MRAM.

In an exemplary embodiment of the present application, a perpendicular magnetization MTJ device is provided. As shown in FIG. 1, the device includes a reference layer 2, an insulating barrier layer 3, a free layer 4, and an enhancement layer which are sequentially disposed one on another. 5. The decoupling layer 6 and the pinned layer 7, wherein the reference layer 2 is opposite to the magnetization direction of the pinned layer 7, and the reinforcing layer 5 is for enhancing the perpendicular magnetic anisotropy of the free layer 4, the demagnetization coupling The layer 6 is used for isolating the above-mentioned free layer 4 from the above-mentioned fixed layer 7, so that the magnetization direction of the free layer can be independently inverted without being affected by the magnetization direction of the fixed layer, so that the fixed layer generates the free layer only during the STT writing process. effect. The magnetization directions of the free layer, the reference layer, and the pinned layer are perpendicular to the film plane (i.e., the thickness direction of each layer).

Since the magnetization direction of the reference layer in the prior art is fixed, the magnetization direction of the above fixed layer is also fixed. Here, "fixed" does not mean absolute fixation, which is relative to the change of the magnetization direction of the free layer, that is, the change of the magnetization direction of the reference layer and the fixed layer is difficult, and the materials of the two are difficult. The coercive force is large, the magnetization direction of the free layer is relatively easy to change, and the corresponding material has a small coercive force.

In the above-described perpendicular magnetization MTJ device, in the process of writing data by using the spin transfer torque effect, electrons flowing from the fixed layer to the free layer or from the free layer to the fixed layer apply a moment to the free layer, and the MTJ device (ie, vertical) The magnetized MTJ device, hereinafter the MTJ device also represents a perpendicular magnetization MTJ device, applies a forward bias voltage such that electrons flow from the fixed layer to the reference layer, and after being fixed through the fixed layer, the electrons polarized by the fixed layer will be free layers. Applying a moment such that the direction of magnetization of the free layer is the same as the direction of magnetization of the fixed layer. On the other hand, in the process of electron flow from the free layer to the reference layer, the pole of the free layer is reflected from the reference layer due to the spin filtering effect of the reference layer. The electrons exert a moment on the free layer such that the direction of magnetization of the free layer is opposite to the direction of magnetization of the reference layer. Since the direction of magnetization of the reference layer and the fixed layer are opposite, the direction of the moment applied by the reference layer and the fixed layer to the free layer is uniform.

In summary, the direction of the moment of the fixed layer to the free layer is consistent with the direction of the reference layer to the free layer, thereby making the free layer more likely to flip, reducing the critical write current and reducing the energy consumption of the STT-MRAM chip. At the same time, the data writing rate is also improved, and the fixed layer can cancel the scattered magnetic field of the reference layer acting on the free layer to avoid mutual interference between different bits; in addition, the enhancement layer in the above perpendicular magnetization MTJ device can be enhanced The magnetic anisotropy of the free layer, which in turn increases the thermal stability of the free layer.

In the perpendicular magnetization MTJ device of the present application, the coercive force of the free layer is smaller than the coercive force of the reference layer and the fixed layer. For the relationship between the coercive force of the fixed layer and the reference layer, in one embodiment of the present application, the above The coercive force of the reference layer and the above fixed layer is H _c1 and H _c2 , where H _c1 >H _c2 . That is, the direction of magnetization is more difficult to change with respect to the reference layer relative to the fixed layer.

In another embodiment of the present application, the coercive force of the reference layer and the fixed layer is H _c1 and H _c2 , wherein H _c2 >H _c1 . That is, the magnetization direction is more difficult to change with respect to the fixed layer relative to the reference layer.

In still another embodiment of the present application, the reference layer and the fixed layer respectively comprise a plurality of magnetic layers, and the magnetic layer having the smallest distance from the insulating barrier layer in the reference layer is a reference magnetic layer, and the fixed layer is The magnetic layer having the smallest distance of the demagnetization coupling layer is a fixed magnetic layer, and the reference magnetic layer is opposite to the magnetization direction of the above fixed magnetic layer.

The material of the reference layer in the present application may be selected from any material in the prior art that satisfies the performance requirements of the reference layer, and those skilled in the art may select a suitable material according to the actual situation.

In order to further ensure the performance of the reference layer, in one embodiment of the present application, the material of the reference layer is selected from the group consisting of Co, Ni, Fe, CoFe, CoNi, NiFe, CoFeNi, CoB, FeB, CoFeB, NiFeB, Pt, Pd, One or more of PtPd, FePt, Ir, Ru, Re, Rh, B, Zr, V, Nb, Ta, Mo, W, Cu, Ag, Au, Al, and Hf. The reference layer is typically a multilayer film structure that requires adjustment of the type and thickness of each layer of film such that its magnetization direction is perpendicular to its interface.

In still another embodiment of the present application, the material of the insulating barrier layer is selected from the group consisting of a magnesium oxide compound, a silicon oxide compound, a silicon nitride compound, an aluminum oxide compound, a magnesium aluminum oxide compound, a titanium oxide compound layer, a germanium oxygen compound, and a calcium. One or more of an oxygen compound and a ferrite compound. These materials have good insulation properties and can further ensure the good performance of the perpendicular magnetization MTJ device.

The insulating barrier layer and the second insulating layer in the present application are not limited to the various material layers mentioned above, and those skilled in the art can select a suitable material layer as the insulating barrier layer according to actual conditions.

In one embodiment of the present application, the thickness of the insulating barrier layer is between 0.5 and 20 nm in order to obtain a suitable RA (resistance value of the perpendicular magnetization MTJ device).

A person skilled in the art can select any material in the prior art that can satisfy the performance requirements of the free layer as a material of the free layer according to actual conditions.

In still another embodiment of the present application, the material of the free layer is selected from the group consisting of Co, Fe, Ni, Pt, Pd, Ru, Ta, Cu, CoB, FeB, NiB, CoFe, NiFe, CoNi, CoFeNi, CoFeB, NiFeB. One or more of CoNiB, CoFeNiB, FePt, FePd, CoPt, CoPd, CoFePt, CoFePd, FePtPd, CoPtPd and CoFePtPd. These materials are relatively easy to obtain and further ensure that the perpendicular magnetization MTJ device has good performance.

In order to further ensure that the reinforcing layer of the present application can enhance the perpendicular magnetic anisotropy of the free layer, thereby enhancing the thermal stability of the free layer, in one embodiment of the present application, the material of the reinforcing layer is selected from the group consisting of Ag, Au, Pt, One or more of Pd, Rh, Ru, Re, Mo, Hf, Ir, Ni, Nb, W and V.

Of course, the material of the reinforcing layer of the present application is not limited to the materials mentioned above, and those skilled in the art may select other materials that meet the performance requirements of the reinforcing layer to form the reinforcing layer according to actual conditions.

In another embodiment of the present application, the thickness of the reinforcing layer is between 0.2 and 1 nm, which further ensures that the reinforcing layer can effectively increase the perpendicular magnetic anisotropy of the free layer.

In still another embodiment of the present application, the material of the demagnetization coupling layer is selected from one or more of Cu, Al, Cr, Ta, Zr, TaN and TiN, and the material can effectively isolate the free layer and the fixed layer. .

Of course, the material of the demagnetization coupling layer of the present application is not limited to the materials mentioned above, and those skilled in the art may select other materials that meet the requirements according to actual conditions to form the above-mentioned demagnetization coupling layer of the present application.

In order to further ensure the isolation of the demagnetization coupling layer and to avoid the inversion of the polarized electrons during the transmission process, in one embodiment of the present application, the demagnetization coupling layer has a thickness of between 0.5 and 10 nm.

In still another embodiment of the present application, the material of the fixing layer is selected from the group consisting of Co, Ni, Fe, CoFe, CoNi, NiFe, CoFeNi, CoB, FeB, CoFeB, NiFeB, Pt, Pd, PtPd, FePt, Ir, Ru. One or more of Re, Rh, B, Zr, V, Nb, Ta, Mo, W, Cu, Ag, Au, Al, and Hf. This further ensures the effect of the pinned layer on the free layer, thereby ensuring that the perpendicular magnetized MTJ device has a small critical write current.

Of course, the material of the fixed layer of the present application is not limited to the above materials, and those skilled in the art can select other materials that meet the performance requirements of the fixed layer according to actual conditions.

In still another embodiment of the present application, as shown in FIG. 2, the perpendicular magnetization MTJ device further includes a first electrode layer 1 and a second electrode layer 8, wherein the first electrode layer 1 is disposed away from the reference layer 2 The surface of the insulating barrier layer 3 is disposed on the surface of the fixed layer 7 away from the demagnetization coupling layer 6.

A forward bias voltage V1 is applied to the MTJ device, that is, the first electrode layer 1 applies a forward voltage, and the second electrode layer 8 applies a negative voltage or 0, so that electrons flow from the fixed layer 7 to the reference layer 2, and are polarized through the fixed layer 7. The electrons apply a moment to the free layer 4 such that the direction of magnetization of the free layer 4 is the same as the direction of magnetization of the fixed layer 7, and on the other hand, during the flow of electrons from the free layer 4 to the reference layer 2, due to spin filtering of the reference layer 2. Function, the polarized electrons reflected from the reference layer 2 back to the free layer 4 apply a moment to the free layer 4 such that the magnetization direction of the free layer 4 is opposite to the magnetization direction of the reference layer 2, since the reference layer 2 and the fixed layer 7 have opposite magnetization directions, Therefore, the direction of the moment applied by the reference layer 2 and the fixed layer 7 to the free layer 4 is uniform, so that the magnetization direction of the free layer 4 is opposite to the magnetization direction of the reference layer 2, thereby writing data "0".

Applying a reverse bias voltage V ₁ ' to the MTJ device (the current direction of V ₁ ' and V ₁ is opposite, and the absolute values of the two may be equal or unequal, for different devices, both The absolute value has a different magnitude relationship, such that electrons flow from the reference layer 2 to the fixed layer 7, and electrons polarized through the reference layer 2 apply a moment to the free layer 4 such that the magnetization direction of the free layer 4 is the same as the magnetization direction of the reference layer 2, On the other hand, in the process of electrons flowing from the free layer 4 to the fixed layer 7, the polarized electrons reflected from the fixed layer 7 back to the free layer 4 also exert a moment on the free layer 4 due to the spin filtering action of the fixed layer 7. Therefore, the magnetization direction of the free layer 4 is opposite to the magnetization direction of the fixed layer 7. Since the magnetization directions of the reference layer 2 and the fixed layer 7 are opposite, the direction of the moment applied by the reference layer 2 and the fixed layer 7 to the free layer 4 is uniform, which makes the freedom The magnetization direction of the layer 4 is the same as the magnetization direction of the reference layer 2, thereby writing data "1".

In another exemplary embodiment of the present application, an STT-MRAM is provided, the STT-MRAM comprising a perpendicular magnetization MTJ device, any of the above-described perpendicular magnetization MTJ devices.

The above STT-MRAM includes the above-described perpendicular magnetization MTJ device, so that its chip energy consumption is small and the writing efficiency is high.

In order to make the technical solutions of the present application more clear to those skilled in the art, the technical solutions of the present application will be described below in conjunction with specific embodiments.

Example 1

The STT-MRAM memory includes a plurality of MTJ devices, and further includes a switching circuit electrically connected to the MTJ device, and the switching circuit includes a switch, a word line, a bit line, and a source line. The specific connection relationship is the same as that in the prior art, and will not be described here.

The structure of the MTJ unit is as shown in FIG. 2, the first electrode layer 1 is a Ta layer, and the thickness is

The reference layer 2 includes a plurality of structural layers, which are oriented away from the first electrode layer.

Wherein the reference structural layer is CoFeB, the magnetization direction is perpendicular to the film plane (ie, the thickness direction of each layer); the insulating barrier layer 3 is a MgO layer, and the thickness thereof is

The forbidden band width η ₁ = 7.6 eV; the free layer 4 is

a thick CoFeB layer; the reinforcing layer 5 is a Pd layer, the thickness of which is

The demagnetization coupling layer 6 is a Cu layer, and its thickness is

The fixed layer 7 includes a plurality of structural layers, and in the direction away from the demagnetization coupling layer 6

Wherein, the CoFe in the fixed layer is a fixed structural layer whose magnetization direction is perpendicular to the film plane (ie, the thickness direction of each layer).

Example 2

The difference from Embodiment 1 is that the thickness of the reinforcing layer is

The thickness of the demagnetization coupling layer is

Example 3

The thickness of the demagnetization coupling layer is

Example 4

Example 5

The difference from Embodiment 1 is that the thickness of the demagnetization coupling layer is

Comparative example

The difference from the embodiment is that the perpendicular magnetization MTJ device does not have a reinforcement layer, a demagnetization coupling layer, and a pinned layer between the second electrode layer and the free layer.

The MTJ device was etched into bits having a diameter of 100 nm, and the critical write current density of the example and the comparative example was tested at room temperature using an electrical and magnetic test system at a write time of 50 μA. The specific test results are shown in Table 1.

Table 1

Critical write current density (A/cm ² )

Write time (ns)

实施例1Example 1	2.5×10⁵A/cm² 2.5×10 ⁵ A/cm ²	10ns10ns
实施例2Example 2	3.5×10⁵A/cm² 3.5×10 ⁵ A/cm ²	12ns12ns
实施例3Example 3	4×10⁵A/cm² 4×10 ⁵ A/cm ²	15ns15ns
实施例4Example 4	7×10⁵A/cm² 7×10 ⁵ A/cm ²	30ns30ns
实施例5Example 5	9×10⁵A/cm² 9×10 ⁵ A/cm ²	35ns35ns
对比例Comparative example	3×10⁶A/cm² 3×10 ⁶ A/cm ²	40ns40ns

As can be seen from the data in the above table, compared with the comparative example, the critical write current of each embodiment is small, and the write time is short, thereby reducing the power consumption of the STT-MRAM chip and improving the writing of the STT-MRAM chip. Into the efficiency; wherein, in comparison with Embodiment 1, the thickness of the reinforcing layer in the MTJ device of Embodiment 4 is

more than the

Therefore, its critical write current is larger than that of Embodiment 1, and the writing time is longer than that of Embodiment 1; compared with Embodiment 1, the thickness of the demagnetization coupling layer in the MTJ device of Embodiment 5 is

It is smaller, so its critical write current is larger than that of Embodiment 1, and the writing time is longer than that of Embodiment 1.

From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects:

1) In the perpendicular magnetization MTJ device of the present application, the direction of the moment of the fixed layer to the free layer is the same as the direction of the reference layer to the free layer, thereby making the free layer more susceptible to flipping, reducing the critical write current, and reducing the STT. - The energy consumption of the MRAM chip also increases the data writing rate, and the fixed layer can cancel the scattered magnetic field of the reference layer acting on the free layer to avoid mutual interference between different bits; in addition, the above perpendicular magnetization MTJ The enhancement layer in the device enhances the magnetic anisotropy of the free layer, thereby increasing the thermal stability of the free layer.

2) The STT-MRAM of the present application, since including the above-described perpendicular magnetization MTJ device, has a small chip energy consumption and high storage efficiency.

The above description is only the preferred embodiment of the present application, and is not intended to limit the present application, and various changes and modifications may be made to the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this application are intended to be included within the scope of the present application.

Claims

A perpendicular magnetization MTJ device, characterized in that the perpendicular magnetization MTJ device comprises a reference layer (2), an insulating barrier layer (3), a free layer (4), an enhancement layer (5), and a magnetic coupling layer (6) and a fixed layer (7), wherein the reference layer (2) is opposite to a magnetization direction of the fixed layer (7), and the reinforcing layer (5) is for reinforcing the free layer ( 4) perpendicular magnetic anisotropy, the demagnetization coupling layer (6) is used to isolate the free layer (4) from the fixed layer (7).
The perpendicular magnetization MTJ device according to claim 1, wherein a coercive force of the reference layer (2) and the fixed layer (7) is H c1 and H c2 , wherein H c1 > H c2 .
The perpendicular magnetization MTJ device according to claim 1, wherein the reference layer (2) and the fixed layer (7) have a coercive force of H c1 and H c2 , wherein H c2 > H c1 .
The perpendicular magnetization MTJ device according to claim 1, wherein the reference layer (2) and the fixed layer (7) each comprise a plurality of magnetic layers, and the reference layer (2) is The magnetic layer having the smallest distance of the insulating barrier layer (3) is a reference magnetic layer, and the magnetic layer having the smallest distance from the demagnetization coupling layer (6) in the fixed layer (7) is a fixed magnetic layer, and the reference magnetic layer The magnetization direction is opposite to that of the fixed magnetic layer.
The perpendicular magnetization MTJ device according to claim 1, wherein the material of the reference layer (2) is selected from the group consisting of Co, Ni, Fe, CoFe, CoNi, NiFe, CoFeNi, CoB, FeB, CoFeB, NiFeB, Pt One or more of Pd, PtPd, FePt, Ir, Ru, Re, Rh, B, Zr, V, Nb, Ta, Mo, W, Cu, Ag, Au, Al and Hf.
The perpendicular magnetization MTJ device according to claim 1, wherein the material of the insulating barrier layer (3) is selected from the group consisting of a magnesium oxide compound, a silicon oxide compound, a silicon nitride compound, an aluminum oxide compound, a magnesium aluminum oxide compound, One or more of the titanium oxide compound layer, the oxynitride compound, the calcium oxy compound and the ferrite compound, preferably the insulating barrier layer (3) has a thickness of between 0.5 and 20 nm.
The perpendicular magnetization MTJ device according to claim 1, wherein the material of the free layer (4) is selected from the group consisting of Co, Fe, Ni, Pt, Pd, Ru, Ta, Cu, CoB, FeB, NiB, CoFe One or more of NiFe, CoNi, CoFeNi, CoFeB, NiFeB, CoNiB, CoFeNiB, FePt, FePd, CoPt, CoPd, CoFePt, CoFePd, FePtPd, CoPtPd and CoFePtPd.
The perpendicular magnetization MTJ device according to claim 1, wherein the material of the enhancement layer (5) is selected from the group consisting of Ag, Au, Pt, Pd, Rh, Ru, Re, Mo, Hf, Ir, Ni, Nb. One or more of W and V, preferably the reinforcing layer (5) has a thickness of between 0.2 and 1 nm.
The perpendicular magnetization MTJ device according to claim 1, wherein the material of the demagnetization coupling layer (6) is selected from one or more of Cu, Al, Cr, Ta, Zr, TaN and TiN. Preferably, the demagnetization coupling layer (6) has a thickness of between 0.5 and 10 nm.
The perpendicular magnetization MTJ device according to claim 1, wherein the material of the fixed layer (7) is selected from the group consisting of Co, Ni, Fe, CoFe, CoNi, NiFe, CoFeNi, CoB, FeB, CoFeB, NiFeB, Pt. , Pd, PtPd, One or more of FePt, Ir, Ru, Re, Rh, B, Zr, V, Nb, Ta, Mo, W, Cu, Ag, Au, Al, and Hf.
The perpendicular magnetization MTJ device according to claim 1, wherein the perpendicular magnetization MTJ device further comprises:

a first electrode layer (1) disposed on a surface of the reference layer (2) remote from the insulating barrier layer (3);

A second electrode layer (8) is disposed on a surface of the fixed layer (7) remote from the demagnetization coupling layer (6).
An STT-MRAM comprising a perpendicular magnetization MTJ device, characterized in that the perpendicular magnetization MTJ device is the perpendicular magnetization MTJ device according to any one of claims 1 to 11.