Voltage regulated magnetic memory cell and magnetic memory

Abstract

A voltage regulated magnetic memory cell and magnetic memory are provided. The magnetic memory cell includes a bottom electrode, a top electrode, and a magnetic tunnel junction between the bottom electrode and the top electrode. The magnetic tunnel junction includes a reference layer over the bottom electrode, the reference layer having a fixed direction of perpendicular magnetization; a barrier layer over the reference layer; a free layer over the barrier layer, the free layer having a variable direction of perpendicular magnetization; a magnetic bias layer over the free layer, the magnetic bias layer having a fixed direction of perpendicular magnetization, the magnetic bias layer having an interlayer exchange coupling with the free layer; and a regulation layer between the free layer and the magnetic bias layer, the regulation layer configured to regulate the interlayer exchange coupling between the free layer and the magnetic bias layer based on a voltage between the bottom electrode and the top electrode.

Description

Technical Field

[0001] This invention relates to the field of magnetic memory technology, and in particular to a voltage-regulated magnetic memory cell and a magnetic memory. Background Technology

[0002] Magnetic Random Access Memory (MRAM) has attracted widespread attention from industry and academia due to its advantages such as non-volatility, high-speed read / write, low power consumption, and unlimited erase / write cycles. The energy consumption of current-driven STT-MRAM or SOT-MRAM limits further technological development; therefore, developing lower-energy-consumption MRAM technology is one of the core requirements of current information technology development. Voltage-regulated magnetic anisotropy (VCMA) can achieve electric field-driven magnetization reversal under the magnetic moment precession mechanism, significantly reducing the critical current density for reversing the magnetic moment in STT and SOT effects, and has shown potential research value in low-power magnetic storage. However, the voltage regulation coefficient in the VCMA effect is small, and the voltage pulse width requirement is very high, posing significant challenges in practical applications. Therefore, it is necessary to propose a new type of magnetic random access memory that is easily voltage-regulated. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a voltage-regulated magnetic storage unit and a magnetic memory, which can achieve the flipping of the free layer by regulating the exchange coupling between magnetic layers in a magnetic tunnel junction.

[0004] On one hand, the present invention provides a voltage-regulated magnetic storage cell, comprising: a bottom electrode, a top electrode, and a magnetic tunnel junction located between the bottom electrode and the top electrode, wherein the magnetic tunnel junction comprises:

[0005] A reference layer is located above the bottom electrode, and the reference layer has a fixed vertical magnetization.

[0006] A barrier layer is located above the reference layer;

[0007] A free layer, located above the barrier layer, has a vertically magnetized layer with a variable orientation;

[0008] A magnetic bias layer is located above the free layer. The magnetic bias layer has a fixed vertical magnetization and interlayer exchange coupling with the free layer.

[0009] An adjustment layer, located between the free layer and the magnetic bias layer, is used to adjust the interlayer exchange coupling between the free layer and the magnetic bias layer according to the voltage between the bottom electrode and the top electrode.

[0010] Optionally, the adjustment layer includes:

[0011] The first oxide layer is located close to the free layer;

[0012] The second oxide layer is located close to the magnetic bias layer;

[0013] A non-magnetic metal layer is located between the first oxide layer and the second oxide layer.

[0014] Optionally, the materials of the first oxide layer and the second oxide layer include one of MgO, HfO2, NiO and Al2O3.

[0015] Optionally, the material of the non-magnetic metal layer includes one of Ir, Ru, W, Ta, Mo, Nb, and Hf.

[0016] Optionally, it further includes: a first pinning layer located between the bottom electrode and the reference layer, for fixing the magnetization direction of the reference layer.

[0017] Optionally, it further includes: a second pinning layer located between the magnetic bias layer and the top electrode, for fixing the magnetization direction of the magnetic bias layer.

[0018] On the other hand, the present invention provides a magnetic memory comprising the voltage-regulated magnetic storage unit described above.

[0019] The voltage-controlled magnetic storage cell provided by this invention is based on the exchange coupling between voltage-controlled magnetic layers. An adjustment layer is added between the two magnetic layers of a magnetic tunnel junction. By applying different voltages to both ends of the magnetic tunnel junction, the exchange coupling between the two magnetic layers can oscillate and be regulated, thereby controlling the ferromagnetic and antiferromagnetic coupling between the two magnetic layers and achieving voltage-controlled switching of the magnetic free layer of the magnetic tunnel junction. Compared with existing technologies, this solves the problem of requiring an external magnetic field or current for magnetic tunnel junction switching, thus reducing the power consumption of the magnetic tunnel junction and increasing its switching speed. It also addresses the high energy consumption and latency issues encountered in the miniaturization of magnetic memories. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a voltage-controlled magnetic storage cell according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of a voltage-controlled magnetic storage cell according to an embodiment of the present invention;

[0022] Figure 3 for Figure 2 The diagram shows the voltage regulation effect of the embodiment. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0025] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0026] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0027] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0028] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0029] This invention provides a voltage-regulated magnetic storage cell, specifically an STT-MRAM storage cell, such as... Figure 1 As shown, the voltage-regulated magnetic storage cell 10 includes a bottom electrode 101, a magnetic tunnel junction 102, and a top electrode 103, with the magnetic tunnel junction 102 located between the bottom electrode 101 and the top electrode 103. The bottom electrode 101 can be a Ta film to reduce surface roughness and promote the growth and crystal orientation formation of ultrathin multilayer films. The top electrode 103 is a Ta film.

[0030] The magnetic tunnel junction 102 includes, from bottom to top, a reference layer 1021, a barrier layer 1022, a free layer 1023, a conditioning layer 1024, and a magnetic bias layer 1025. The reference layer 1021 is located close to and above the bottom electrode 101, and has a fixed-direction vertical magnetization. The reference layer 1021 can be made of one of Co, Fe, CoFe, CoFeB, CoFeAl, Hulser alloy, and MnGa, and has a thickness of 1.5 nm.

[0031] The barrier layer 1022 is located above the reference layer 1021. It is made of MgO and has a thickness of 1.5 nm. It is used to provide tunneling effect and voltage-controlled magnetic anisotropy (VCMA) effect.

[0032] The free layer 1023 is located above the barrier layer 1022. The free layer 1023 has a variable direction of vertical magnetization. The material of the free layer 1023 can be one of Co, Fe, CoFe, CoFeB, CoFeAl, Hulser alloy and MnGa, and the thickness is 1 nm.

[0033] A magnetic bias layer 1025 is located above the free layer 1023. The magnetic bias layer 1025 has a fixed-direction vertical magnetization and interlayer exchange coupling with the free layer 1023. The magnetic bias layer 1025 is one of Co, Fe, CoFe, CoFeB, CoFeAl, Hulser alloy, and MnGa, and has a thickness of 1.5 nm.

[0034] The regulating layer 1024 is located between the free layer 1023 and the magnetic bias layer 1025, and is used to regulate the interlayer exchange coupling between the free layer 1023 and the magnetic bias layer 1025 according to the voltage between the bottom electrode 101 and the top electrode 103. It is particularly noteworthy that, because the regulating effect of the regulating layer 1024 is related to the voltage between the bottom electrode 101 and the top electrode 103, the flipping of the magnetic tunnel junction can be controlled by voltage, which will be further explained later.

[0035] In one embodiment, the regulating layer 1024 comprises a three-layer film structure, including a first oxide layer, a second oxide layer, and a non-magnetic metal layer located between the first oxide layer and the second oxide layer. The first oxide layer is adjacent to the free layer 1023, and the second oxide layer is adjacent to the magnetic bias layer 1025. The materials of the first oxide layer and the second oxide layer include one of MgO, HfO2, NiO, and Al2O3. The material of the non-magnetic metal layer includes one of Ir, Ru, W, Ta, Mo, Nb, and Hf, and its thickness is generally 0.05–1 nm. The overall thickness of the regulating layer 1024 is 0.5–2 nm. For example, the regulating layer 1024 may consist of two MgO layers with an Ir layer sandwiched in between, where the thickness of the two MgO layers is 0.5 nm and the thickness of the Ir layer is 0.2 nm, which can be represented as MgO(0.5 nm) / Ir(0.2 nm) / MgO(0.5 nm).

[0036] Furthermore, Figure 2 A method for demonstrating Figure 1 An improved structure. For example... Figure 2 As shown, the voltage-regulated magnetic storage cell 11 includes a bottom electrode 111, a magnetic tunnel junction 112, and a top electrode 113. The magnetic tunnel junction 112 is located between the bottom electrode 111 and the top electrode 113. The magnetic tunnel junction 112 includes, from bottom to top, a first pinning layer 1121, a reference layer 1122, a barrier layer 1123, a free layer 1124, a regulating layer 1125, a magnetic bias layer 1126, and a second pinning layer 1127. Compared to Figure 1 The structure, Figure 2 The magnetic tunnel junction incorporates a first pinning layer 1121 and a second pinning layer 1127. The first pinning layer 1121 is located between the bottom electrode 111 and the reference layer 1122, and is used to fix the magnetization direction of the reference layer 1122. The first pinning layer 1121 can be a Co / Pt multilayer film. The second pinning layer 1127 is located between the magnetic bias layer 1126 and the top electrode 113, and is used to fix the magnetization direction of the magnetic bias layer 1126. The second pinning layer 1127 can also be a Co / Pt multilayer film. The bottom electrode 111, top electrode 113, reference layer 1122, barrier layer 1123, free layer 1124, adjustment layer 1125, and magnetic bias layer 1126 can all be referenced... Figure 1 Description of each layer in the illustrated embodiment.

[0037] Furthermore, according to Figure 2 The stacked structure of voltage-regulated magnetic storage cells is shown. Figure 3 The materials used in each layer are shown in detail, and the magnetic coupling between the free layer and the magnetic bias layer is illustrated when different voltages are applied. Figure 3This illustrates that the regulating effect of the regulating layer 1125 is related to the voltage between the bottom electrode 111 and the top electrode 113. For example... Figure 3 As shown in (a), when a voltage of 0.5V is applied between the top electrode 113 and the bottom electrode 111, the free layer 1124 and the magnetic bias layer 1126 form a ferromagnetic coupling; as Figure 3 As shown in (b), when a voltage of 1.5V is applied between the top electrode 113 and the bottom electrode 111, the free layer 1124 and the magnetic bias layer 1126 form an antiferromagnetic coupling.

[0038] As can be seen, in this embodiment, the adjustment layer between the free layer and the magnetic bias layer can serve as a resonant tunneling layer. When different voltages are applied to both ends of the magnetic tunnel junction, the adjustment layer can cause oscillations and modulation of the exchange coupling between the free layer and the magnetic bias layer, thereby adjusting the ferromagnetic and antiferromagnetic coupling between the free layer and the magnetic bias layer, and thus achieving the flipping of the free layer. That is, the magnetic tunnel junction can flip without the need for an external magnetic field or external current, and the flipping of the free layer can be controlled by applying a voltage in only one direction.

[0039] On the other hand, this embodiment also provides a magnetic memory, which includes the voltage-controlled magnetic storage unit of the above embodiment.

[0040] The above embodiments are merely specific implementations of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A voltage-regulated magnetic storage unit, characterized in that, include: A bottom electrode, a top electrode, and a magnetic tunnel junction located between the bottom electrode and the top electrode, the magnetic tunnel junction comprising: A reference layer is located above the bottom electrode, and the reference layer has a fixed vertical magnetization. A barrier layer is located above the reference layer; A free layer, located above the barrier layer, has a vertically magnetized layer with a variable orientation; A magnetic bias layer is located above the free layer. The magnetic bias layer has a fixed vertical magnetization and interlayer exchange coupling with the free layer. An adjustment layer, located between the free layer and the magnetic bias layer, is used to adjust the interlayer exchange coupling between the free layer and the magnetic bias layer according to the voltage between the bottom electrode and the top electrode, so that the free layer and the magnetic bias layer form ferromagnetic coupling or antiferromagnetic coupling.

2. The voltage-regulated magnetic storage unit according to claim 1, characterized in that, The adjustment layer includes: The first oxide layer is located close to the free layer; The second oxide layer is located close to the magnetic bias layer; A non-magnetic metal layer is located between the first oxide layer and the second oxide layer.

3. The voltage-regulated magnetic storage unit according to claim 2, characterized in that, The materials of the first oxide layer and the second oxide layer include one of MgO, HfO2, NiO and Al2O3.

4. The voltage-regulated magnetic storage unit according to claim 2, characterized in that, The material of the non-magnetic metal layer includes one of Ir, Ru, W, Ta, Mo, Nb, and Hf.

5. The voltage-regulated magnetic storage unit according to claim 1, characterized in that, Also includes: The first pinning layer, located between the bottom electrode and the reference layer, is used to fix the magnetization direction of the reference layer.

6. The voltage-regulated magnetic storage unit according to claim 1, characterized in that, Also includes: The second pinning layer, located between the magnetic bias layer and the top electrode, is used to fix the magnetization direction of the magnetic bias layer.

7. A magnetic storage device, characterized in that, Includes a voltage-regulated magnetic storage cell as described in any one of claims 1 to 6.

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