Magnetic memory

Abstract

The application relates to a magnetic memory, comprising: an MTJ device, comprising a first electrode, an MTJ layer and an AFM layer, the MTJ layer being arranged between the first electrode and the AFM layer; a second electrode, arranged on a side of the AFM layer away from the MTJ layer; and a heater, arranged on a side of the second electrode away from the AFM layer, used for heating the AFM layer to demagnetize the AFM layer; wherein in a write mode, a write current flows from one end of the second electrode to the other end. The magnetic memory places the heater on the side of the second electrode away from the AFM layer to heat the AFM layer, which can effectively demagnetize the AFM layer completely; after demagnetization, the magnetization direction of the AFM layer is determined by the SOT effect generated by the write current passing through the bottom electrode, and then the exchange bias between the AFM layer and the free layer is flipped, so that the magnetic moment of the free layer is flipped. The demagnetization of the AFM layer adopts the heat generated by the separate heater, and does not need to demagnetize the AFM layer through the Joule effect of the increased write current, so that the write power consumption of the storage chip is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of magnetic electronic devices, and in particular to a magnetic memory. Background Technology

[0002] With the continuous emergence and development of emerging technologies such as the Internet of Things, artificial intelligence, and metaverse, the requirements for information storage are constantly increasing, and information storage technology is facing increasingly severe challenges. However, current storage technologies, despite continuous improvements in process nodes, still struggle to improve reliability at extremely small sizes. Therefore, there is an urgent need to explore a new memory mechanism that balances high density, high reliability, and high speed. Magnetic storage chips, with their characteristics of high speed, low power consumption, non-volatility, and radiation resistance, hold the promise of further breaking through the bottlenecks of traditional silicon-based electronic devices in the "post-Moore's Law era."

[0003] The third-generation magnetic memory—spin-orbit magnetic memory—offers significant improvements in power consumption, lifespan, and operating speed compared to the previous two generations. While this third-generation magnetic memory chip achieves an order-of-magnitude performance boost, its inherent limitations still prevent it from meeting the demands for data storage reliability and high-speed read / write operations at smaller process nodes. Therefore, a disruptive technological breakthrough is still needed for magnetic memory.

[0004] EB-MRAM, a magnetic memory that utilizes the intrinsic exchange bias of antiferromagnetic and ferromagnetic layers for information storage, holds promise as the fourth generation of magnetic memory. It achieves data writing from "0" to "1" by reversing the magnetic moment of the ferromagnetic free layer through a change in the exchange bias direction. This storage mechanism can remain stable at several atomic scales, potentially significantly improving chip capacity, speed, and reliability. The reversal of the exchange bias primarily relies on the magnetic order reversal of the antiferromagnetic layer. The main process of antiferromagnetic reversal is the remagnetization of the crystal lattice after thermal demagnetization. Thermal demagnetization is crucial for antiferromagnetic magnetic order reversal, but the introduction of Joule heating significantly increases the write power consumption of the memory chip. Therefore, improving the Joule heating effect of the current is particularly critical for reducing the Joule heating effect in EB-MRAM. Summary of the Invention

[0005] Therefore, it is necessary to provide a magnetic memory that can effectively reduce the power consumption of memory chips during writing, in order to address the aforementioned technical problems.

[0006] This invention provides a magnetic storage device, comprising: An MTJ device includes a first electrode, an MTJ layer, and an AFM layer, wherein the MTJ layer is disposed between the first electrode and the AFM layer; The second electrode is disposed on the side of the AFM layer facing away from the MTJ layer; A heater is disposed on the side of the second electrode opposite to the AFM layer, for heating the AFM layer to demagnetize it. In write mode, the write current flows from one end of the second electrode to the other end.

[0007] In one embodiment, the MTJ layer is an MTJ film stack, comprising a pinned layer, a reference layer, a barrier layer and a free layer stacked sequentially, wherein the pinned layer is bonded to the first electrode and the free layer is bonded to the AFM layer.

[0008] In one embodiment, the heater includes a heating layer and an insulating layer. The heating layer is made of a high resistivity conductor material. The heating layer and the insulating layer are disposed in close contact. The side of the insulating layer facing away from the heating layer is disposed in close contact with the second electrode.

[0009] In one embodiment, the heating layer uses a high resistivity conductor material of TiN and / or TaN.

[0010] In one embodiment, the heater further includes an insulation layer having two receiving slots, and the heating layer includes a heating element and two conductive connecting parts connected to the heating element, the two conductive connecting parts being respectively received in the receiving slots.

[0011] In one embodiment, the top of the insulation layer has a recessed platform, the heating element is placed in the recessed platform, and the insulating layer is closely attached to the heating layer to enclose the heating layer in the insulation layer.

[0012] In one embodiment, the insulating layer and the heat insulation layer are made of SiO and / or SiN.

[0013] In one embodiment, the AFM layer is made of an antiferromagnetic material, including IrMn, PtMn, IrMn3, and Mn3Sn.

[0014] In one embodiment, the second electrode is made of a material with the SOT effect, including heavy metal materials and two-dimensional materials.

[0015] In one embodiment, a plurality of MTJ devices are disposed on the top of the second electrode, and each MTJ device is configured with a heater.

[0016] In the aforementioned magnetic memory, a heater is placed on the side of the second electrode facing away from the AFM layer to heat the AFM layer. Because the second electrode is very thin (nanometer-scale), it has almost no impact on the heating effect, effectively demagnetizing the AFM layer completely. After demagnetization, the magnetization direction of the AFM layer is determined by the SOT effect generated when a write current is applied to the bottom electrode, thereby reversing the exchange bias between the AFM layer and the free layer, achieving a magnetic moment reversal in the free layer. The demagnetization of the AFM layer uses heat generated by a separate heater, eliminating the need for the Joule effect through increased write current, thus effectively reducing the write power consumption of the memory chip. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a magnetic storage device according to one embodiment; Figure 2 A perspective view of a heater according to one embodiment; Figure 3 for Figure 2 Cross-sectional view of the heating element; Figure 4 This is a cross-sectional view of a heater according to another embodiment; Figure 5 This is a schematic diagram of a magnetic memory with multiple MTJ devices. Figure 6 for Figure 5 A cross-sectional view of a magnetic storage device.

[0019] Figure label: 110, MTJ device; 112, first electrode; 114, MTJ layer; 116, AFM layer; 120, second electrode; 130, heater; 132, insulating layer; 134, heating layer; 136, heat insulation layer. Detailed Implementation

[0020] 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, 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.

[0021] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this specification are for illustrative purposes only and do not represent the only possible implementation.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0025] The following is combined Figures 1-6 The magnetic storage device of the present invention is described.

[0026] like Figure 1 As shown, in one embodiment, a magnetic memory includes an MTJ device 110, a second electrode 120, and a heater 130.

[0027] The MTJ device 110 includes a first electrode 112, an MTJ layer 114 and an AFM layer 116, with the MTJ layer 114 disposed between the first electrode 112 and the AFM layer 116.

[0028] Among them, the first electrode 112 is the top electrode layer, MTJ is the magnetic tunnel junction device, and AFM layer is the antiferromagnetic layer.

[0029] Specifically, the MTJ layer is an MTJ film stack, comprising a pinned layer, a reference layer, a tunneling barrier layer, and a free layer stacked sequentially. The pinned layer is bonded to the first electrode 112, and the free layer is bonded to the AFM layer 116. The AFM layer 116 mainly uses collinear antiferromagnetic materials or non-collinear antiferromagnetic materials, including but not limited to IrMn, PtMn, IrMn3, and Mn3Sn.

[0030] The second electrode 120 is disposed on the side of the AFM layer 116 facing away from the MTJ layer 114.

[0031] The second electrode 120 is the bottom electrode layer.

[0032] Specifically, the bottom electrode layer uses materials with strong SOT (spin-orbit moment) effect, such as heavy metal materials Pt, Ta, W, etc., as well as two-dimensional materials, such as WTe2.

[0033] Heater 130 is disposed on the side of the second electrode 120 facing away from the AFM layer 116, and is used to heat the AFM layer 116 to demagnetize the AFM layer 116.

[0034] In write mode, the write current flows from one end of the second electrode 120 to the other. Write mode is the mode for writing data to the magnetic memory.

[0035] In this embodiment of the magnetic memory, the heater 130 is placed on the side of the second electrode 120 facing away from the AFM layer 116 to heat the AFM layer 116. Because the thickness of the second electrode 120 is small, at the nanometer level, it has almost no impact on the heating effect, and can effectively demagnetize the AFM layer 116 completely. After demagnetization, the magnetization direction of the AFM layer 116 is from the bottom electrode through which the write current I is applied. write Subsequently, the resulting SOT effect determines the switching bias between the AFM layer and the free layer, thereby achieving the magnetic moment reversal of the free layer. The demagnetization of the AFM layer 116 is achieved by generating heat through a separate heater 130, eliminating the need for demagnetization of the AFM layer through the Joule effect of increasing the write current, thus effectively reducing the write power consumption of the memory chip.

[0036] like Figure 2 , Figure 3 and Figure 4 As shown, in one embodiment, the heater 130 includes a heating layer 134 and an insulating layer 132. The heating layer 134 is made of a high resistivity conductor material. The heating layer 134 and the insulating layer 132 are disposed in close contact. The side of the insulating layer 132 facing away from the heating layer 134 is disposed in close contact with the second electrode 120.

[0037] The heating layer 134 uses TiN and / or TaN as its high resistivity conductor material. A heating current I is passed through the heater 130. heat The heating current passes through the heating layer 134, generating Joule heat at the heating layer 134, which makes the AFM layer 116 flip more effectively, thereby flipping the bias and realizing the reversal of the free layer magnetic moment. The heater 130 is small in size, uses a high-resistivity conductor material to generate high heat, and a small current is sufficient to completely demagnetize the AFM layer 116. The insulating layer 132 is made of SiO and / or SiN. The insulating layer 132 can effectively prevent crosstalk between the heating current and the writing current. It should be noted that the conductor material includes, but is not limited to, TiN and TaN, and the insulating layer 132 includes, but is not limited to, SiO and SiN.

[0038] Specifically, the heater 130 also includes an insulation layer 136, which has two receiving grooves. The heating layer 134 includes a heating part and two conductive connecting parts connected to the heating part. The top of the heating part is in close contact with the insulation layer 132, and the two conductive connecting parts are respectively received in the receiving grooves.

[0039] The top of the insulation layer 136 has a recessed platform, and the heating element is placed in the recessed platform. The insulation layer 132 is closely attached to the heating layer 134 and encloses the heating layer 134 in the insulation layer 136 to reduce heat loss in the insulation layer 136 and improve the heat transfer efficiency in the insulation layer 132.

[0040] The insulation layer 136 is made of SiO and / or SiN. The insulation layer 136 is thicker than the insulating layer 132, ranging from tens to hundreds of nanometers, to prevent heat loss and shunting. It should be noted that the materials used in the insulation layer 136 include, but are not limited to, SiO and SiN.

[0041] like Figure 5 and Figure 6 As shown, in one embodiment, a plurality of MTJ devices 110 are disposed on the top of the second electrode 120 of the magnetic memory, and each MTJ device 110 is respectively configured with a heater 130.

[0042] Specifically, multiple MTJ devices 110 are fabricated on the same relatively long bottom electrode, and a write current I is applied. write The SOT effect can be applied to all devices, but SOT is insufficient to flip the switching bias. For the device that needs to be written with information, a heating current I is applied below. heat This demagnetizes the AFM and induces a flip-flop via the SOT effect. In this write mode, the current I used to generate the SOT effect... write It is the writing current, while the heating current I is... heat It can be used as a gate current to enable the write current I. writeWrite information to the selected device.

[0043] The magnetic memory of this invention adds a heater 130 to heat the AFM layer 116, which promotes the switching bias flip, reduces the write current and write power consumption, and, in conjunction with the spin orbit moment (SOT) effect, can complete the deterministic flip of the antiferromagnetic moment, thereby realizing the writing of information into EB-MRAM. By using the switching bias to control the direction of the free layer magnetic moment, the free layer magnetic moment can have a stronger resistance to external magnetic field interference, which facilitates device miniaturization, has a higher magnetic moment retention, increases data retention, and improves storage density. Compared with the third-generation magnetic memory (SOT-MRAM), it has obvious miniaturization characteristics and data retention characteristics. In addition, the write current and heating current of the magnetic memory of this invention do not flow through the MTJ device 110, which improves the device life.

[0044] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0045] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A magnetic storage device, characterized in that, include: An MTJ device includes a first electrode, an MTJ layer, and an AFM layer, wherein the MTJ layer is disposed between the first electrode and the AFM layer; The second electrode is disposed on the side of the AFM layer facing away from the MTJ layer; A heater is disposed on the side of the second electrode opposite to the AFM layer, for heating the AFM layer to demagnetize it. In write mode, the write current flows from one end of the second electrode to the other. The heater includes a heating layer and an insulating layer, the heating layer and the insulating layer being disposed in close contact, and the side of the insulating layer facing away from the heating layer being disposed in close contact with the second electrode. The heater also includes a heat insulation layer. A heating current is passed through the heater, but the heating current does not flow through the MTJ device.

2. The magnetic storage device according to claim 1, characterized in that, The MTJ layer is an MTJ film stack, comprising a pinned layer, a reference layer, a barrier layer and a free layer stacked sequentially. The pinned layer is bonded to the first electrode and the free layer is bonded to the AFM layer.

3. The magnetic storage device according to claim 1, characterized in that, The heating layer is made of a high resistivity conductor material.

4. The magnetic storage device according to claim 3, characterized in that, The heating layer uses TiN and / or TaN as the high resistivity conductor material.

5. The magnetic storage device according to claim 3, characterized in that, The insulation layer has two receiving slots, and the heating layer includes a heating element and two conductive connecting parts connected to the heating element, with the two conductive connecting parts respectively housed in the receiving slots.

6. The magnetic storage device according to claim 5, characterized in that, The top of the insulation layer has a recessed platform, the heating element is placed in the recessed platform, and the insulating layer is closely attached to the heating layer to enclose the heating layer in the insulation layer.

7. The magnetic storage device according to claim 5, characterized in that, The insulating layer and the heat insulation layer are made of SiO and / or SiN.

8. The magnetic storage device according to claim 1, characterized in that, The AFM layer uses antiferromagnetic materials, including IrMn, PtMn, IrMn3, and Mn3Sn.

9. The magnetic storage device according to claim 1, characterized in that, The second electrode is made of a material with the SOT effect, including heavy metal materials and two-dimensional materials.

10. The magnetic storage device according to any one of claims 1 to 9, characterized in that, The top of the second electrode is provided with multiple MTJ devices, and each MTJ device is configured with a heater.

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