Storage unit, forming method of storage unit, data writing method and memory

Abstract

The invention relates to the technical field of semiconductors, in particular to a storage unit, a forming method of the storage unit, a data writing method and a memory. The spin-orbit moment layer, the insulating layer and the magnetic tunnel junction layer are sequentially located on the substrate, and the magnetic tunnel junction layer comprises a free layer, a tunnel layer and a reference layer which are stacked; wherein the insulating layer is used for reducing the thermal diffusion influence on the free layer when the spin orbit moment layer is electrified; the spin orbit moment layer is used for generating spin current and tunneling through the insulating layer to enter the free layer under the action of external voltage so as to overturn the magnetization direction in the free layer, so that the quantity, speed and the like of the spin current entering the free layer can be controlled through the external voltage, the data reading and writing speed is more controllable, and the data reading and writing efficiency is improved. And the writing cost is lower.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing, and particularly to a storage cell, a method for forming a storage cell, a data writing method, and a memory. Background Art

[0002] As a new type of memory, Spin Orbit Torque Magnetic Random Access Memory (abbreviated as SOT-MRAM) has a fast writing speed, which can reach sub-nanosecond writing speed. The write current density is low, which can be two orders of magnitude lower than that of two-terminal devices based on spin transfer torque. In addition, the reading and writing of SOT-MRAM are separated, and the read information is based on the tunneling magnetoresistance TMR of Magnetic Tunnel Junctions (MTJs).

[0003] The information writing of SOT-MRAM is based on spin orbit torque (including but not limited to spin Hall effect, Rashba effect), and only needs to pass a current through a writing line at the bottom of the free layer. The write current of SOT-MRAM does not pass through the MTJ, and will not cause durability problems of the MTJ.

[0004] There are mainly three types of SOT-MRAM in the related art, namely Type Z, Type Y, and Type X. However, for Type Z and Type X SOT-MRAM, an external magnetic field is required to flip the magnetization of the free layer, and the external magnetic field makes it difficult to miniaturize the size of the storage device, which is not conducive to high-density integration. Type Y SOT-MRAM does not require external magnetic field assistance, but the flipping speed is slow. Summary of the Invention

[0005] The present application provides a storage cell, a method for forming a storage cell, a data writing method, and a memory to at least solve the above problems existing in the related art.

[0006] To solve the above technical problems, the technical solution of the present application is as follows:

[0007] According to a first aspect of an embodiment of the present application, a storage cell is provided, including: a substrate; a spin orbit torque layer, an insulating layer, and a magnetic tunnel junction layer sequentially located on the substrate, where the magnetic tunnel junction layer includes a stacked free layer, a tunnel layer, and a reference layer; wherein, the insulating layer is used to reduce the thermal diffusion effect of the spin orbit torque layer on the free layer when the spin orbit torque layer is energized; the spin orbit torque layer is used to generate a spin current, and under the action of an external voltage, tunnel through the insulating layer and enter the free layer to flip the magnetization direction in the free layer.

[0008] In a second aspect of the embodiments of the present application, a method for forming a storage unit is provided. The forming method includes: providing a substrate; forming a spin-orbit torque material layer on the substrate; forming an insulating material layer on the spin-orbit torque material layer; forming a magnetic tunnel junction material layer on the insulating material layer; sequentially etching the magnetic tunnel junction material layer, the insulating material layer, and the spin-orbit torque material layer to form the magnetic tunnel junction layer, the insulating layer, and the spin-orbit torque layer; wherein the insulating layer is used to reduce the thermal diffusion effect of the spin-orbit torque layer on the free layer when the spin-orbit torque layer is energized; the spin-orbit torque layer is used to generate a spin current, and under the action of an external voltage, tunnel through the insulating layer into the free layer to flip the magnetization direction in the free layer.

[0009] In a third aspect of the embodiments of the present application, a method for writing data into a storage unit is provided. The data writing method includes: applying a first voltage to one end of the spin-orbit torque layer and a second voltage to the other end of the spin-orbit torque layer, where the first voltage is less than the second voltage; writing a current into the other end of the spin-orbit torque layer so that the spin-orbit torque layer generates a spin current based on the written current; applying an external voltage so that the spin current tunnels through the insulating layer into the free layer under the action of the external voltage to flip the magnetization direction in the free layer to achieve data reading and writing.

[0010] In a fourth aspect of the embodiments of the present application, a memory is provided, and the memory includes the storage unit as described in any one of the above embodiments.

[0011] The technical solutions provided by the embodiments of the present application at least bring the following beneficial effects:

[0012] The storage unit, method for forming a storage unit, data writing method, and memory provided by embodiments of the present application form a spin-orbit torque layer on a substrate, an insulating layer on the surface of the spin-orbit torque layer facing away from the substrate, and a magnetic tunnel junction layer on the surface of the insulating layer facing away from the spin-orbit torque layer, so that an insulating layer is formed on the surface of the spin-orbit torque layer facing away from the substrate. On the one hand, this insulating layer can increase the distance between the free layer in the magnetic tunnel junction and the spin-orbit torque layer, reduce the thermal diffusion effect of the spin-orbit torque layer on the free layer when the spin-orbit torque layer is energized, and reduce the temperature of the free layer. On the other hand, since the magnetic moment of the free layer comes from the interface between the free layer and the insulating layer, an insulating layer is formed on the lower surface of the free layer in the storage unit provided by the embodiments of the present application, and a tunnel layer is formed on the free layer. This tunnel layer can also be considered an insulating layer, that is, the present application is equivalent to forming two interfaces between the free layer and the insulating layer, so that the magnetic moment of the free layer becomes double, thereby increasing the stability of the prepared storage unit, so that the device can be miniaturized to achieve the purpose of reducing power consumption and operating voltage. In addition, the spin-orbit torque layer is used to generate a spin current, and under the action of an external voltage, it tunnels through the insulating layer into the free layer to flip the magnetization direction in the free layer, so that the quantity, speed, etc. of the spin current entering the free layer can be controlled by the external voltage, making the data reading and writing speed more controllable and the writing cost lower.

[0013] It should be understood that the above general description and subsequent detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The drawings herein are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application, and do not constitute an improper limitation to the present application.

[0015] Figure 1 FIG. shows a schematic structural diagram of a conventional SOT-MRAM element 10.

[0016] Figure 2 FIG. shows a schematic structural diagram of a conventional SOT-MRAM cell 100 including an SOT-MRAM element during a write operation.

[0017] Figure 3 FIG. shows a schematic structural diagram of a conventional SOT-MRAM cell 100 including an SOT-MRAM element during a read operation.

[0018] Figure 4 FIG. is a schematic diagram of a spin hall effect shown according to an exemplary embodiment.

[0019] Figure 5Schematic diagrams of Type Z, Type Y, and Type X SOT-MRAM shown according to an exemplary embodiment.

[0020] Figure 6 Schematic diagram of the structure of an MRAM with a ferromagnet embedded in a hard mask for shaping the SOT layer shown according to an exemplary embodiment.

[0021] Figure 7 Schematic diagram of the structure of a storage cell shown according to an exemplary embodiment Figure 1 。

[0022] Figure 8 Schematic diagram of the structure of a storage cell shown according to an exemplary embodiment Figure 2 。

[0023] Figure 9 Flow schematic diagram of a method for forming a storage cell shown according to an exemplary embodiment Figure 1 。

[0024] Figure 10 Flow schematic diagram of a method for forming a storage cell shown according to an exemplary embodiment Figure 2 。

[0025] Figure 11 Flow schematic diagram of a method for forming a storage cell shown according to an exemplary embodiment Figure 3 。

[0026] Figure 12 Flow schematic diagram of a method for reading and writing data of a storage cell shown according to an exemplary embodiment.

[0027] The following is a supplementary description of the reference numerals:

[0028] 10 - SOT-MRAM element, 20 - magnetic tunnel junction layer, 21 - reference layer, 210 - pinned magnetization, 22 - tunnel layer, 23 - free layer, 230 - free magnetization, 30 - spin-orbit torque layer, 31 - SOT current, 100 - SOT-MRAM cell, 40 - first transistor, 41 - second transistor, 32 - read current, 50 - insulating layer, 60 - first metal hard mask layer, 70 - fixed layer, 80 - magnet layer, 90 - second metal hard mask layer. Detailed implementation manners

[0029] The following provides many different embodiments or examples for implementing different features of the provided subject matter. Specific examples of components and configurations are described below in a simplified manner. Of course, these components and configurations are only examples and are not intended to be restrictive. For example, in the following description, the formation of a first feature above or on a second feature may include embodiments in which the first feature and the second feature are formed in direct contact, and may also include embodiments in which additional features may be formed between the first feature and the second feature such that the first feature and the second feature are not in direct contact. In addition, this application may repeat reference numerals and / or letters in various examples. This repetition is for simplicity and clarity purposes and does not itself indicate a relationship between the various embodiments and / or configurations discussed.

[0030] Additionally, spatial relative terms, such as "below", "beneath", "lower", "above", "upper", "front", "back", "over" and similar terms, may be used in this application for ease of description to describe the relationship of one element or feature to another (other) element or feature as illustrated in the figures. Spatial relative terms are intended to encompass different orientations in addition to the orientation depicted in the figures during the use or operation of the device.

[0031] Now, a detailed description will be given in conjunction with the accompanying drawings of the problems existing in the existing SOT - MRAM.

[0032] First, an introduction to SOT - MRAM is given:

[0033] Figure 1 A schematic structural diagram of a conventional SOT - MRAM element 10 is shown. Here, SOT is an abbreviation for Spin - Orbit Torque, and its Chinese name is spin - orbit torque. MRAM is an abbreviation for Magnetoresistive Random Access Memory, and its Chinese name is magnetic random access memory. The SOT - MRAM element 10 includes a magnetic tunnel junction layer (Magnetic Tunnel Junction, MTJ) 20, which includes a tunnel layer 22 sandwiched between a reference layer 21 with pinned magnetization 210 and a free layer 23 with free magnetization 230. The SOT - MRAM element 10 further includes a spin - orbit torque layer 30 that extends generally parallel to the plane of layers 21 - 23 and contacts the MTJ 20 at its first end (on the side of the free layer 23). The spin - orbit torque layer 30 is configured to apply a torque to the second magnetization 230 through a SOT current 31 suitable for switching. In particular, through the spin - Hall effect and / or the Rashba - Edelstein effect, the SOT current 31 applies a torque to the initial orientation of the free magnetization 230 such that the orientation of the free magnetization 230, for example, changes from parallel to the pinned magnetization 210 to anti - parallel to the pinned magnetization 210.

[0034] The SOT-based switch allows for the use of a lower current density and independent read and write paths. The pinned magnetization 210 and the free magnetization 230 can be perpendicular to the plane of layers 21, 23 (as shown in Figure 1 ), or parallel to the plane of layers 21, 23.

[0035] Figure 2 FIG. shows a schematic structural diagram of a conventional SOT-MRAM cell 100 including an SOT-MRAM element during a write operation. Figure 3 FIG. shows a structural diagram of a conventional SOT-MRAM cell 100 including an SOT-MRAM element during a read operation. As shown in Figure 2 and 3 described, the conventional SOT-MRAM cell 100 includes an SOT-MRAM element 10, a bit line BL connected to one end of the spin-orbit torque layer, and a source line SL connected to the MTJ 20 via a first transistor 40. The first transistor 40 is connected to the second end of the MTJ 20 opposite to the first end (on the side of the reference layer 21). The source line SL is further connected to the other end of the spin-orbit torque layer 30 via a second transistor 41. The gate of the first transistor 40 is controlled by the read word line WLR, and the gate of the second transistor 41 is controlled by the write word line WLW. The SOT-MRAM cell 100 forms a single-level cell (SLC) circuit of three terminals, two transistors, and one resistor (i.e., 2T1R).

[0036] As shown in Figure 2 , an appropriate positive or negative write voltage Vwrite is applied to the bit line BL, and the source line SL is set to "0". The write word line WLW is biased to "1" to control the second transistor 41 to be in the conduction mode, so that the SOT current 31 can pass through the spin-orbit torque layer 30. The first transistor 40 is in the closed mode "0", and no current flows in the MTJ 20. Alternatively, instead of applying a negative voltage to the BL, a positive write voltage Vwrite can be applied to the SL, and the BL is set to "0".

[0037] As shown in Figure 3 , during the read operation, an appropriate read voltage Vread is applied to the bit line BL, and the source line SL is set to "0". The read word line WLR is biased to "1" to control the first transistor 40 to be in the conduction mode, so that the read current 32 can pass through the MTJ 20. The second transistor 41 is in the closed mode, and no current flows in the spin-orbit torque layer 30.

[0038] A significant advantage of SOT devices over STT devices is that the write current does not pass through the tunneling layer, enabling a very high number of device erase / write cycles. This write current can be a spin current, which mainly comes from the spin Hall effect.

[0039] Figure 4 It is a schematic diagram of the spin Hall effect shown according to an exemplary embodiment. As Figure 4 shown, the spin Hall effect means that when a current passes through a heavy metal, due to the strong spin-orbit coupling of heavy metal atoms, spin-up electrons and spin-down electrons are deflected and accumulated towards the two side interfaces of the heavy metal layer perpendicular to the current direction, that is, spin accumulation, and then a pure spin current is generated and flows towards the free layer.

[0040] In the related art, there are mainly three types of SOT-MRAM, namely Type Z, Type Y, and Type X. Figure 5 It is a schematic diagram of Type Z, Type Y, and Type X SOT-MRAM shown according to an exemplary embodiment.

[0041] As Figure 5 shown, Type Z SOT-MRAM is a magnetic random access memory of the out-of-plane perpendicular magnetization reversal type, which is a magnetic random access memory with perpendicular magnetic anisotropy. The magnetic moment of the magnetic tunnel junction MTJ perpendicular to the free layer can be deviated from the perpendicular direction by a preset angle through an external magnetic field, and then the magnetization of the free layer is reversed by the spin transfer torque generated by the write current applied to the SOT bottom electrode layer to write data into the magnetic tunnel junction MTJ.

[0042] Continuing as Figure 5 shown, Type Y SOT-MRAM is a magnetic random access memory of the in-plane horizontal magnetization reversal type. The current applied to the SOT bottom electrode layer can directly determine the magnetization reversal direction of the free layer of the magnetic tunnel junction MTJ without the assistance of an external magnetic field, thereby achieving data writing.

[0043] Continuing as Figure 5 shown, similar to Type Z SOT-MRAM, the magnetization direction of the free layer is perpendicular to the torque generated by the SOT effect. Type X SOT-MRAM also requires an external magnetic field to assist in breaking the inversion symmetry of the spin-orbit torque, thereby achieving a directional reversal of the free layer magnetic moment.

[0044] However, for Type Y SOT-MRAM, although the magnetic moment of the free layer can be flipped without an external magnetic field, the flipping speed is slow. For Type X and Type Z SOT-MRAM, if an external magnetic field is required, it is difficult to miniaturize the storage device size, which is not conducive to high-density integration.

[0045] To solve the problem that an external magnetic field is required for Type X and Type Z SOT-MRAM, related technologies also embed a ferromagnet in the hard mask used to shape the SOT layer. Using this ferromagnet, a small uniform in-plane field is induced on the free layer of the magnetic tunnel junction layer. Figure 6 As shown in the schematic diagram of the structure of an MRAM with a ferromagnet embedded in the hard mask for shaping the SOT layer according to an exemplary embodiment, as Figure 6 shown, a Co magnet layer can be provided in the hard mask for shaping the SOT layer, which is equivalent to having a magnet in each MRAM.

[0046] As described above, the magnetic moment flipping speed of the free layer of Type Y SOT-MRAM is slow, and an external magnetic field is required for Type X and Type Z SOT-MRAM. Based on this, the embodiments of the present application provide a storage cell, a method for forming a storage cell, a data writing method, and a memory to solve the above problems existing in the prior art.

[0047] Figure 7 is a schematic structural diagram of a storage cell shown according to an exemplary embodiment Figure 1 Please refer to Figure 7 and this storage cell may include:

[0048] a substrate;

[0049] a spin-orbit torque layer 30 located on the substrate;

[0050] an insulating layer 50 located on the surface of the spin-orbit torque layer facing away from the substrate;

[0051] a magnetic tunnel junction layer 20 located on the surface of the insulating layer facing away from the spin-orbit torque layer, and the magnetic tunnel junction layer 20 includes a free layer 23 stacked on the insulating layer, a tunnel layer 22 stacked on the free layer, and a reference layer 21 stacked on the tunnel layer;

[0052] wherein, the insulating layer 50 is used to reduce the thermal diffusion effect of the spin-orbit torque layer 30 on the free layer 23 when the spin-orbit torque layer 30 is energized; the spin-orbit torque layer 30 is used to generate a spin current, and under the action of an external voltage, the spin current tunnels through the insulating layer 50 into the free layer 23 to flip the magnetization direction in the free layer 23.

[0053] As Figure 7 shown, a substrate (not shown) can be provided. The substrate serves as a carrier for supporting various structures such as the spin-orbit torque layer 30 and the magnetic tunnel junction layer 20, and the substrate can be a silicon substrate or a germanium substrate, etc. A CMOS device can be formed in the substrate, and the CMOS device can be, for example, an NMOS transistor and / or a PMOS transistor, etc.; an isolation structure can also be formed in the substrate, and the isolation structure is a shallow trench isolation structure or a local oxidation of silicon (LOCOS) isolation structure. Similarly, a conductive member can also be formed in the substrate, and the conductive member can be a gate, a source, or a drain of a transistor, or a metal interconnect structure electrically connected to the transistor, etc. Circuit structures such as word lines and bit lines can also be provided in the substrate. For example, the substrate sequentially includes a first interlayer insulating layer, a diffusion barrier layer, and a second interlayer insulating layer from top to bottom. Among them, the materials of the first interlayer insulating layer and the second interlayer insulating layer can be interlayer oxide insulating layers prepared from oxide insulating materials. Specifically, the first interlayer insulating layer and the second interlayer insulating layer can be prepared from oxide insulating materials such as silicon oxide and silicon oxynitride. The material of the diffusion barrier layer therein can be silicon nitride and other materials. Two metal wirings can be formed in the first interlayer insulating layer, and two metal vias penetrate through the diffusion barrier layer and the second interlayer insulating layer. The two metal wirings correspond to the two metal vias one by one. Each metal via is formed above the corresponding metal wiring. The distance between the two metal vias is determined by the metal wiring design, so as to be electrically connected to the spin-orbit torque layer, conduct an electron current to the spin-orbit torque layer, or read the electrical parameters of the magnetic tunnel junction layer 20. The materials of the metal wiring and the metal via can be cobalt, tungsten, copper, ruthenium, etc.

[0054] Continuing as Figure 7 shown, a spin-orbit torque layer 30 can be formed on the substrate, and the spin-orbit torque layer 30 is electrically connected to the two metal vias. The spin-orbit torque layer 30 includes at least one of a non-magnetic heavy metal material, a topological insulator material, and an antiferromagnetic conductor material. Among them, the non-magnetic heavy metal material can include at least one of Pt, Ta, W, Ru, Ir, Ti, and Bi, the topological insulator material can include at least two of Bi, Te, and Se, and the antiferromagnetic conductor material can include at least two of Pt, Mn, and Ir. In some embodiments, the material of the spin-orbit torque layer 30 is a topological insulator material, which can not only better ensure that the magnetization direction of the free layer is a predetermined direction, but also achieve an ultra-low write current density, reducing the energy consumption of the storage unit.

[0055] Continuing as Figure 7As shown, an insulating layer 50 can be formed on the surface of the spin-orbit torque layer 30 facing away from the substrate. Optionally, the insulating layer 50 is made of an oxide insulating material. Exemplarily, the oxide insulating material includes one or more of magnesium oxide compounds, silicon oxide compounds, silicon nitride compounds, aluminum oxide compounds, magnesium aluminum oxide compounds, titanium oxide layers, tantalum oxide compounds, calcium oxide compounds, and iron oxide compounds. Exemplarily, "thermal diffusion effect" can refer to the degree of influence of thermal diffusion when the spin-orbit torque layer is energized on the free layer.

[0056] In some embodiments, a bottom electrode layer can also be formed on the substrate, and the spin-orbit torque layer 30 is located on the surface of the bottom electrode layer facing away from the substrate. Exemplarily, the material of the bottom electrode layer includes Ta, TaN, Ti, or TiN, etc.

[0057] In some embodiments, since the insulating layer 50 can reduce the thermal diffusion effect of the spin-orbit torque layer 30 on the free layer when it is energized and reduce the interaction between the spin-orbit torque layer 30 and the free layer 23, the thickness of the insulating layer 50 can be related to the degree of influence of thermal diffusion of the spin-orbit torque layer 30 on the free layer when it is energized. In addition, the thickness of the insulating layer 50 can also be related to the thickness loss caused by planarization processes such as, but not limited to, chemical mechanical planarization on the surface of the insulating layer before the subsequent formation of the magnetic tunnel junction layer. The embodiments of the present application do not limit the thickness of the insulating layer.

[0058] In the embodiments of the present application, by forming an insulating layer 50 on the surface of the spin-orbit torque layer 30 facing away from the substrate, on the one hand, the insulating layer 50 can increase the distance between the free layer and the spin-orbit torque layer in the magnetic tunnel junction layer, reduce the interaction between the spin-orbit torque layer and the free layer, reduce the thermal diffusion effect of the spin-orbit torque layer on the free layer when it is energized, and reduce the temperature of the free layer. On the other hand, since the magnetic moment of the free layer comes from the interface between the free layer and the insulating layer, in the storage unit provided by the embodiments of the present application, an insulating layer is formed on the lower surface of the free layer, and a tunnel layer is formed on the free layer. The tunnel layer can also be regarded as an insulating layer, that is, the present application is equivalent to forming two interfaces of the free layer and the insulating layer, so that the magnetic moment of the free layer becomes double, thereby increasing the stability of the prepared storage unit, so that the device can be miniaturized to achieve the purpose of reducing power consumption and operating voltage.

[0059] In other embodiments, in order to quickly transmit the spin current generated when the spin-orbit torque layer conducts an electron current to the free layer, increase the speed of magnetization reversal of the free layer, and achieve fast reading and writing of data, a transmission device capable of transmitting spin current may also be disposed in the insulating layer. One end of the transmission device is in contact with the surface of the spin-orbit torque layer facing away from the substrate, and the other end of the transmission device is flush with the surface of the insulating layer facing away from the spin-orbit torque layer, so as to contact the free layer in the magnetic tunnel junction layer. The shape of the transmission device may specifically include, but is not limited to, columnar structures such as cylinders and prisms. When determining the material of the transmission device, an insulating antiferromagnetic material may be used as the material of the transmission device. The insulating antiferromagnetic material may be nickel oxide, which can increase the transmission distance of the spin current transmitted through the transmission device, so that a thicker insulating layer and transmission device can be designed, and thus the etching process window can be improved.

[0060] In other embodiments, a conductive structure may also be disposed in the insulating layer, and the conductive structure is electrically connected to the free layer and the spin-orbit torque layer. That is, the conductive structure can serve as a bridge for passing current between the spin-orbit torque layer and the free layer, so that the spin-orbit torque layer and the conductive structure are used as part of the structure in the read channel to redesign a new read channel to solve the problem of poor or ineffective original read channel caused by the material of the transmission device generally being an insulating material. When specifically arranging the conductive structure, there are various arrangement methods. As long as it can be ensured that the conductive structure is located in the insulating layer, and the end face of the conductive structure between the insulating layer and the spin-orbit torque layer is electrically connected to the spin-orbit torque layer; at the same time, the end face of the conductive structure between the insulating layer and the free layer is electrically connected to the free layer, the conductive structure can be electrically connected to the free layer and the spin-orbit torque layer. Exemplarily, the material of the conductive structure may specifically be a metal or alloy such as tungsten, ruthenium, tantalum, or cobalt.

[0061] Continue as Figure 7 As shown, a magnetic tunnel junction layer 20 may be formed on the surface of the insulating layer 50 facing away from the spin-orbit torque layer 30. The magnetic tunnel junction layer 20 includes a free layer 23 stacked on the insulating layer 50, a tunnel layer 22 stacked on the free layer 23, and a reference layer 21 stacked on the tunnel layer 22. In practical applications, the magnetic tunnel junction layer may be fabricated into a tapered structure with a larger lower end and a smaller upper end.

[0062] Optionally, the material of the reference layer 21 can be selected from one or more of Co, Ni, Fe, CoFe, CoNi, NiFe, CoFeNi, CoB, FeB, CoFeB, NiFeB, Pt, Pd, PtPd, FePt, Ir, Ru, Re, Rh, B, Zr, V, Nb, Ta, Mo, W, Cu, Ag, Au, Al, and Hf. That is, it can be a single one or an alloy of several. Those skilled in the art can select a suitable material to form the reference layer of the embodiment of the present application according to the actual situation.

[0063] Optionally, the material of the tunnel layer 22 is selected from one or more of magnesium oxide compounds, silicon oxide compounds, silicon nitride compounds, aluminum oxide compounds, magnesium aluminum oxide compounds, titanium oxide layers, tantalum oxide compounds, calcium oxide compounds, and iron oxide compounds. That is, it can be a single one or a mixture of several. Those skilled in the art can select a suitable material to form the tunnel layer of the embodiment of the present application according to the actual situation.

[0064] Optionally, the material of the free layer 23 is selected from one or more of Co, Fe, Ni, Pt, Pd, Ru, Ta, Cu, CoB, FeB, NiB, CoFe, NiFe, CoNi, CoFeNi, CoFeB, NiFeB, CoNiB, CoFeNiB, FePt, FePd, CoPt, CoPd, CoFePt, CoFePd, FePtPd, CoPtPd, and CoFePtPd. That is, it can be a single one or an alloy of several. Those skilled in the art can select a suitable material to form the free layer of the embodiment of the present application according to the actual situation.

[0065] Optionally, when a transmission device is provided in the insulating layer 50, the magnetic tunnel junction layer 20 is exactly above the transmission device.

[0066] Optionally, the above external voltage is a voltage in the vertical direction, and the vertical direction is the perpendicular direction of the magnetic tunnel junction layer. The voltage in the vertical direction can be applied directly above the magnetic tunnel junction layer 20. The voltage in the vertical direction applied to the magnetic tunnel junction layer 20 is used to enable the spin current generated by the spin-orbit torque layer to tunnel through the insulating layer into the free layer, so as to flip the magnetization direction in the free layer. Thus, the amount, speed, etc. of the spin current entering the free layer can be controlled by applying a voltage in the vertical direction, making the data read / write speed more controllable and the writing cost lower. It should be noted that the magnitude of the voltage in the vertical direction can be set according to actual service requirements, and no specific limitation is made here. In other embodiments, the external voltage can also be a non-vertical voltage, and the non-vertical direction refers to the non-perpendicular direction of the magnetic tunnel junction layer. For example, the external voltage is applied to the magnetic tunnel junction layer 20, and the range of the angle formed between the application direction of the external voltage and the perpendicular direction of the magnetic tunnel junction layer is between 0° and 90°.

[0067] Continue as Figure 7 As shown, a first metal hard mask layer (MHM) 60 can also be laminated on the reference layer 21. The first metal hard mask layer 60 is used as an etching mask for etching to form the magnetic tunnel junction layer 20 and the insulating layer 50. Optionally, the material of the first metal hard mask layer can be selected from one or more of TiN, Ti, Ta, W, TaN, or WN. That is, it can be a single one or several.

[0068] In some embodiments, a protective layer (not shown) can also be formed. The protective layer covers the sidewalls of the magnetic tunnel junction layer 20 and the insulating layer to protect the magnetic tunnel junction layer 20, the insulating layer 50, and the spin-orbit torque layer 30. The material of the protective layer can be silicon nitride, and the thickness of the protective layer can be set according to actual service requirements, and no specific limitation is made here.

[0069] In some embodiments, an interlayer insulating layer (not shown) can also be filled around the protective layer, and the upper surface of the interlayer insulating layer is planarized to facilitate the subsequent formation of the top electrode layer. The material of the interlayer insulating layer can be an oxide insulating material, and specifically, silicon oxide or silicon oxynitride can be used as the oxide insulating material.

[0070] In some embodiments, a top electrode layer (not shown) may also be laminated on the surface of the reference layer 21 facing away from the tunnel layer 22. Further, the top electrode layer is formed above the first metal hard mask layer, and the top electrode layer is electrically connected to the reference layer 21, so that an electron flow can be realized between the reference layer 21 and the top electrode layer. The material of the top electrode layer may be tantalum nitride, titanium nitride, etc. Further, the above external voltage is a voltage in the vertical direction, and the vertical direction is the perpendicular direction of the magnetic tunnel junction layer. The voltage in the vertical direction can be applied to the top electrode layer. Since the top electrode layer is electrically connected to the reference layer 21, applying a voltage in the vertical direction to the top electrode layer can realize an electron flow between the reference layer 21 and the top electrode layer, and quickly cause the spin current generated by the spin-orbit torque layer 30 to tunnel through the insulating layer 50 and enter the free layer 23, so as to realize the flipping of the magnetization direction of the free layer 23.

[0071] Continuing as Figure 7 shown, Figure 7 The storage cell shown is a Type Y SOT-MRAM, that is, it does not require an externally applied magnetic field to realize the directional flipping of the free layer magnetic moment. Instead, by applying an external voltage, the external voltage is used to cause the spin current generated by the spin-orbit torque layer 30 to tunnel through the insulating layer 50 and enter the free layer 23, so as to flip the magnetization direction in the free layer 23. Thus, the amount, speed, etc. of the spin current entering the free layer can be controlled by the external voltage, making the data read / write speed more controllable and the write cost lower. Furthermore, it solves the problems of the existing Type X and Type Z SOT-MRAMs that require an externally applied magnetic field and are difficult to miniaturize the storage device size, which is not conducive to high-density integration, and the problem of the slow magnetic field flipping of the existing Type Y SOT-MRAM. Since the spin current is generated by the spin-orbit torque layer 30, it is equivalent to SOT; and under the action of the external voltage, the spin current can tunnel through the insulating layer 50 and enter the free layer 23, that is, the spin current can tunnel through the magnetic tunnel junction layer 20, which is equivalent to spin-transfer torque (STT). That is, the embodiment of the present application is equivalent to combining an SOT device with an STT device.

[0072] Figure 8 is a schematic structural diagram of a storage cell shown according to an exemplary embodiment Figure 2 Please refer to Figure 8 and the storage cell may include:

[0073] a substrate;

[0074] a spin-orbit torque layer 30 located on the substrate;

[0075] An insulating layer 50 on the surface of the spin-orbit torque layer 30 facing away from the substrate;

[0076] A magnetic tunnel junction layer 20 on the surface of the insulating layer 50 facing away from the spin-orbit torque layer 30, the magnetic tunnel junction layer 20 including a free layer 23 stacked on the insulating layer 50, a tunnel layer 22 stacked on the free layer 23, and a reference layer 21 stacked on the tunnel layer 22;

[0077] Wherein, the insulating layer 50 is used to reduce the thermal diffusion effect of the spin-orbit torque layer 30 when energized on the free layer 23; the spin-orbit torque layer 30 is used to generate a spin current, and under the action of an external voltage, tunnel through the insulating layer 50 into the free layer 23 to flip the magnetization direction in the free layer 23.

[0078] Wherein, the structures and material sources of the substrate, the spin-orbit torque layer 30, the insulating layer 50, and the magnetic tunnel junction layer 20 are similar to those in Figure 7 and will not be elaborated here.

[0079] Continue as in Figure 8 As shown, in an optional embodiment, a fixed layer (HL) 70 may be formed on the surface of the reference layer 21 facing away from the tunnel layer 22, and the fixed layer 70 is used to fix or balance the reference layer 21, and the magnetic field direction in the fixed layer 70 is opposite to the magnetic field direction in the reference layer 21.

[0080] Continue as in Figure 8 As shown, in an optional embodiment, a first metal hard mask layer 60 may also be formed on the surface of the fixed layer 70 facing away from the reference layer 21, and the first metal hard mask layer 60 is used as an etching mask for etching to form the fixed layer 70, the magnetic tunnel junction layer 20, and the insulating layer 50. Optionally, the material of the first metal hard mask layer 60 may be selected from one or more of TiN, Ti, Ta, W, TaN, or WN. That is, it can be a single one or several.

[0081] Continue as in Figure 8 As shown, in an optional embodiment, a magnet layer 80 may also be formed on the surface of the first metal hard mask layer 60 facing away from the fixed layer 70. By using the magnet layer 80, a small uniform in-plane field can be induced on the free layer 23 of the magnetic tunnel junction layer 20, so as to break the inversion symmetry of the spin-orbit torque through this uniform in-plane field, and further realize the directional flipping of the magnetic moment of the free layer 23. Exemplarily, the material of the magnet layer 80 may be sourced from: Fe, C, Ni, Ti, Cr, Mn, etc.

[0082] Continue as in Figure 8As shown, in an optional embodiment, a second metal hard mask layer 90 may be formed on the surface of the magnet layer 80 facing away from the first metal hard mask layer 60, and the second metal hard mask layer 90 is used as an etch mask for etching to form the magnet layer 80 and the spin-orbit torque layer 30. Optionally, the material of the second metal hard mask layer 90 may be selected from one or more of TiN, Ti, Ta, W, TaN, or WN. That is, it may be a single one or several.

[0083] In some embodiments, a protective layer (not shown) may also be formed, and the protective layer covers the sidewalls of the magnetic tunnel junction layer 20, the insulating layer 50, the fixed layer 70, the magnet layer 80, the first metal hard mask layer 60, and the second metal hard mask layer 90 to protect the magnetic tunnel junction layer 20, the insulating layer 50, the fixed layer 70, the magnet layer 80, the first metal hard mask layer 60, and the second metal hard mask layer 90. The material of the protective layer may be silicon nitride, and the thickness of the protective layer may be set according to actual service requirements, and no specific limitation is made thereto.

[0084] In some embodiments, an interlayer insulating layer (not shown) may also be filled around the protective layer, and the upper surface of the interlayer insulating layer is planarized to facilitate the subsequent formation of the top electrode layer. The material of the interlayer insulating layer may be an oxide insulating material, and specifically, silicon oxide or silicon oxynitride may be used as the oxide insulating material.

[0085] In some embodiments, a top electrode layer may also be stacked on the surface of the second metal hard mask layer 90 facing away from the magnet layer 80. The top electrode layer is electrically connected to the reference layer, so that an electron current can be passed between the reference layer 21 and the top electrode layer. The material of the top electrode layer may be tantalum nitride, titanium nitride, etc. Further, the external voltage may be a voltage in the vertical direction, and the vertical direction is the perpendicular direction of the magnetic tunnel junction layer, and the voltage in the vertical direction may be applied to the top electrode layer. Since the top electrode layer is electrically connected to the reference layer, applying a voltage in the vertical direction to the top electrode layer can achieve the passage of an electron current between the reference layer 21 and the top electrode layer, and quickly cause the spin current generated by the spin-orbit torque layer 30 to tunnel through the insulating layer 50 into the free layer 23 to realize the flipping of the magnetization direction of the free layer 23.

[0086] Continue as Figure 8 As shown, since Figure 8 the storage unit in Figure 8The storage unit shown can be a Type Z SOT-MRAM, that is, the flipping of the magnetic moment of the free layer is achieved by the small uniform in-plane field generated by the magnet layer. In addition, by applying an external voltage, the external voltage is used to make the spin current generated by the spin-orbit torque layer tunnel through the insulating layer 50 into the free layer 23 to flip the magnetization direction in the free layer 23, so that the amount, speed, etc. of the spin current entering the free layer can be further controlled by the external voltage, making the data read / write speed more controllable and the writing cost lower. Since the spin current is generated by the spin-orbit torque layer, it is equivalent to SOT; and under the action of the external voltage, this spin current can tunnel through the insulating layer into the free layer, that is, this spin current can tunnel through the magnetic tunnel junction layer, which is equivalent to spin-transfer torque (Spin-Transfer Torque, STT), that is, the embodiment of the present application is equivalent to combining an SOT device with an STT device.

[0087] The embodiment of the present application also provides a method for forming a storage unit. Figure 9 It is a schematic flowchart of a method for forming a storage unit shown according to an exemplary embodiment. Figure 1 As Figure 9 shown, the method for forming the storage unit may include:

[0088] S101. Provide a substrate.

[0089] S103. Form a spin-orbit torque material layer on the substrate.

[0090] S105. Form an insulating material layer on the surface of the spin-orbit torque material layer facing away from the substrate.

[0091] S107. Form a magnetic tunnel junction material layer on the surface of the insulating material layer facing away from the spin-orbit torque layer.

[0092] S109. Etch the magnetic tunnel junction material layer, the insulating material layer, and the spin-orbit torque material layer in sequence to form the magnetic tunnel junction layer, the insulating layer, and the spin-orbit torque layer.

[0093] Wherein, the insulating layer is used to reduce the thermal diffusion effect of the spin-orbit torque layer on the free layer when it is energized; the spin-orbit torque layer is used to generate a spin current, and under the action of an external voltage, tunnel through the insulating layer into the free layer to flip the magnetization direction in the free layer.

[0094] Optionally, in the above step S101, a substrate can be provided, and the structure of this substrate is the same as the structure of the substrate in the above structural embodiment, which will not be elaborated here.

[0095] Optionally, in the above step S103, a spin-orbit torque material layer may be formed on the substrate, and the spin-orbit torque material layer is used to form the spin-orbit torque layer 30 by subsequent etching.

[0096] Optionally, in the above step S105, an insulating material layer may be formed on the surface of the spin-orbit torque material layer facing away from the substrate, and the insulating material layer is used to form the insulating layer 50 by subsequent etching. Exemplarily, the insulating layer 50 is made of an oxide insulating material, and the oxide insulating material includes one or more of magnesium oxide compounds, silicon oxide compounds, silicon nitride compounds, aluminum oxide compounds, magnesium aluminum oxide compounds, titanium oxide compounds, tantalum oxide compounds, calcium oxide compounds, and iron oxide compounds.

[0097] Optionally, in the above step S107, a magnetic tunnel junction material layer may be formed on the surface of the insulating material layer facing away from the spin-orbit torque material layer, and the magnetic tunnel junction material layer is used to form the magnetic tunnel junction layer 20 by subsequent etching. The magnetic tunnel junction material layer includes a free material layer stacked on the insulating material layer, a tunnel material layer stacked on the free material layer, and a reference material layer stacked on the tunnel material layer.

[0098] Exemplarily, the formation process of the magnetic tunnel junction material layer includes, but is not limited to, chemical vapor deposition (CVD), physical vapor deposition (PVD), or atomic layer deposition (ALD) processes.

[0099] Optionally, in the above step S109, the magnetic tunnel junction material layer, the insulating material layer, and the spin-orbit torque material layer may be etched in sequence to form the magnetic tunnel junction layer 20, the insulating layer 50, and the spin-orbit torque layer 30.

[0100] It should be noted that the structures and materials of the magnetic tunnel junction layer 20, the insulating layer 50, and the spin-orbit torque layer 30 are the same as those in the above structural embodiments and will not be elaborated here.

[0101] Figure 10 is a schematic flow chart of a method for forming a storage unit according to an exemplary embodiment Figure 2 , as Figure 10 shown, in an alternative embodiment, after the above step S107, the method may further include: S1081-1. forming a first metal hard mask layer on the surface of the magnetic tunnel junction material layer facing away from the insulating material layer.

[0102] Correspondingly, in the above S109, the above-mentioned etching of the magnetic tunnel junction material layer, the insulating material layer, and the spin-orbit torque material layer in sequence to form the magnetic tunnel junction layer, the insulating layer, and the spin-orbit torque layer may include:

[0103] S1091-1. Etch the first metal hard mask layer, the magnetic tunnel junction material layer, and the insulating material layer in sequence until the surface of the spin-orbit torque layer is exposed, to form the magnetic tunnel junction layer and the insulating layer.

[0104] S1091-3. Form a second metal hard mask layer on the magnetic tunnel junction layer.

[0105] S1091-5. Etch the second metal hard mask layer and the spin-orbit torque layer in sequence until the surface of the substrate is exposed, to obtain the spin-orbit torque layer.

[0106] In this embodiment, a first metal hard mask layer may be formed on the surface of the magnetic tunnel junction material layer facing away from the insulating material layer, and this first metal hard mask layer is used as an etch mask for etching the magnetic tunnel junction layer 20 and the insulating layer 50. Exemplarily, the step of forming the first metal hard mask layer 60 may include: forming a metal hard mask material layer on the surface of the magnetic tunnel junction material layer facing away from the insulating material layer, forming a patterned photoresist layer on this metal hard mask material layer, and etching the metal hard mask material layer with the patterned photoresist layer as a mask until the top surface of the magnetic tunnel junction material layer is exposed, to form a patterned first metal hard mask layer 60.

[0107] Etch the magnetic tunnel junction material layer and the insulating material layer with this first metal hard mask layer 60 as a mask until the surface of the spin-orbit torque layer is exposed, to form the magnetic tunnel junction layer 20 and the insulating layer 50.

[0108] It should be noted that after etching to form the magnetic tunnel junction layer 20 and the insulating layer 50, the first metal hard mask layer 60 may be completely removed, or may be partially etched away. In the case of partial etching, only a part of the first metal hard mask layer 60 with a remaining thickness is still located above the magnetic tunnel junction layer 20.

[0109] In this embodiment, a second metal hard mask layer 90 may also be formed on the magnetic tunnel junction layer 20, and this second metal hard mask layer 90 is used as an etch mask for etching the magnetic tunnel junction layer 20 and the insulating layer 50. Exemplarily, the step of forming the second metal hard mask layer 90 may include: forming a metal hard mask material layer on the magnetic tunnel junction layer 20, forming a patterned photoresist layer on this metal hard mask material layer, and etching the metal hard mask material layer with the patterned photoresist layer as a mask until the top surface of the magnetic tunnel junction layer is exposed, to form a patterned second metal hard mask layer 90.

[0110] Etch the spin-orbit torque layer with this second metal hard mask layer 90 as a mask until the surface of the substrate is exposed, to form the spin-orbit torque layer 30.

[0111] It should be noted that after the spin-orbit torque layer 30 is etched and formed, the second metal hard mask layer 90 can be completely removed or partially etched away. In the case of partial etching, only a remaining part of the second metal hard mask layer 90 with a certain thickness is still located above the magnetic tunnel junction layer.

[0112] In some embodiments, a protective layer (not shown) can also be formed, which covers the sidewalls of the magnetic tunnel junction and the sidewalls of the insulating layer to protect the magnetic tunnel junction layer, the insulating layer, and the spin-orbit torque layer. The material of the protective layer can be silicon nitride, and the thickness of the protective layer can be set according to actual service requirements, and no specific limitation is made thereto.

[0113] In some embodiments, an interlayer insulating layer (not shown) can also be filled around the protective layer, and the upper surface of the interlayer insulating layer is planarized to facilitate the subsequent formation of the top electrode layer. The material of the interlayer insulating layer can be an oxide insulating material, and specifically, silicon oxide or silicon oxynitride can be used as the oxide insulating material.

[0114] Exemplarily, the steps of forming the protective layer and the interlayer insulating layer include: forming a protective material layer on the sidewalls of the magnetic tunnel junction layer and the side surfaces of the insulating layer; filling and forming an interlayer insulating material layer around the protective material layer; planarizing the insulating material layer and the protective material layer until the interlayer insulating material layer and the protective material layer on the top of the magnetic tunnel junction layer are removed, so that the interlayer insulating material layer forms the interlayer insulating layer and the protective material layer forms the protective layer. Exemplarily, the process of forming the protective material layer includes chemical vapor deposition process or atomic layer deposition process, etc.

[0115] In some embodiments, after forming the magnetic tunnel junction layer, the insulating layer, and the spin-orbit torque layer, the method further includes:

[0116] forming a top electrode material layer on the magnetic tunnel junction layer;

[0117] etching the top electrode material layer to obtain a top electrode layer located on the magnetic tunnel junction layer;

[0118] wherein, the external voltage is a voltage in the vertical direction, the voltage in the vertical direction is applied to the top electrode layer, and the vertical direction is the perpendicular direction of the magnetic tunnel junction layer.

[0119] In this embodiment, a top electrode material layer may also be laminated on the surface of the reference layer facing away from the tunnel layer 22. The top electrode material layer is used for subsequent etching to form a top electrode layer on the magnetic tunnel junction layer 20. The top electrode material layer is etched to obtain a top electrode layer on the magnetic tunnel junction layer 20. Exemplarily, the process for forming the top electrode material layer includes atomic layer deposition process or chemical vapor process, etc. Since the top electrode layer is electrically connected to the reference layer, applying a voltage in the vertical direction on the top electrode layer can enable the flow of electron current between the reference layer and the top electrode layer, quickly allowing the spin current generated by the spin-orbit torque layer to tunnel through the insulating layer and enter the free layer, so as to realize the flipping of the magnetization direction of the free layer.

[0120] Figure 11 is a schematic flow chart of a method for forming a memory cell shown according to an exemplary embodiment Figure 3 , such as Figure 11 shown, after the above-mentioned S107, the above method may further include:

[0121] S1082-1. Form a fixing material layer on the surface of the magnetic tunnel junction material layer facing away from the insulating layer.

[0122] S1082-3. Form a first metal hard mask layer on the surface of the fixing material layer facing away from the magnetic tunnel junction material layer.

[0123] Correspondingly, in the above step S109, the above-mentioned sequential etching of the magnetic tunnel junction material layer, the insulating material layer, and the spin-orbit torque material layer to form the magnetic tunnel junction layer, the insulating layer, and the spin-orbit torque layer may include:

[0124] S1092-1. Sequentially etch the first metal hard mask layer, the fixing material layer, the magnetic tunnel junction material layer, and the insulating material layer until the surface of the spin-orbit torque layer is exposed, to form a fixing layer, the magnetic tunnel junction layer, and the insulating layer; the fixing layer is used to fix the reference layer, and the magnetic field direction in the fixing layer is opposite to the magnetic field direction in the reference layer.

[0125] S1092-3. Form a magnet material layer on the first metal hard mask layer.

[0126] S1092-5. Form a second metal hard mask layer on the magnet material layer.

[0127] S1092-7. Sequentially etch the second metal hard mask layer, the magnet material layer, and the spin-orbit torque material layer until the surface of the substrate is exposed, to obtain a magnet layer and the spin-orbit torque layer.

[0128] In this embodiment, a fixed material layer may be formed on the surface of the magnetic tunnel junction material layer facing away from the insulating material layer, and a first metal hard mask layer 60 may be formed on the surface of the fixed material layer facing away from the magnetic tunnel junction material layer. The first metal hard mask layer 60 is used as an etching mask for etching the magnetic tunnel junction layer 20, the insulating layer 50, and the fixed layer 70. Exemplarily, the method of forming the first metal hard mask layer 60 is the same as that in the previous method embodiment and will not be elaborated here.

[0129] Using the first metal hard mask layer 60 as a mask, the magnetic tunnel junction material layer, the insulating material layer, and the fixed material layer are etched until the surface of the spin-orbit torque layer 30 is exposed, thereby forming the magnetic tunnel junction layer 20, the insulating layer 50, and the fixed layer 70.

[0130] It should be noted that after etching to form the magnetic tunnel junction layer 20, the insulating layer 50, and the fixed layer 70, the first metal hard mask layer 60 may be completely removed or partially etched away. In the case of partial removal, only a part of the first metal hard mask layer 60 with a remaining thickness is still located above the magnetic tunnel junction layer.

[0131] In this embodiment, a magnet material layer may also be formed on the magnetic tunnel junction layer 20, and a second metal hard mask layer 90 may be formed on the magnet material layer. The second metal hard mask layer 90 is used as an etching mask for etching the magnet layer and the spin-orbit torque layer. The method of forming the second metal hard mask layer 90 is the same as that in the previous method embodiment and will not be elaborated here.

[0132] Using the second metal hard mask layer 90 as a mask, the magnet material layer and the spin-orbit torque material layer are etched until the surface of the substrate is exposed, thereby forming the magnet layer 80 and the spin-orbit torque layer 30.

[0133] It should be noted that after etching to form the spin-orbit torque layer 30, the second metal hard mask layer 90 may be completely removed or partially etched away. In the case of partial removal, only a part of the second metal hard mask layer with a remaining thickness is still located above the magnet layer 80.

[0134] In some embodiments, a protective layer (not shown) may also be formed. The protective layer covers the sidewalls of the magnetic tunnel junction and the insulating layer to protect the magnetic tunnel junction layer, the insulating layer, the fixed layer, and the spin-orbit torque layer. The material of the protective layer may be silicon nitride, and the thickness of the protective layer may be set according to actual service requirements and will not be specifically limited here.

[0135] In some embodiments, an interlayer insulating layer (not shown) may also be filled around the protective layer, and the upper surface of the interlayer insulating layer is planarized to facilitate the subsequent formation of the top electrode layer. The material of the interlayer insulating layer may be an oxide insulating material, and specifically, silicon oxide or silicon oxynitride may be used as the oxide insulating material.

[0136] Exemplarily, the formation of the protective layer and the interlayer insulating layer is the same as that in the previous method embodiment, and will not be described herein again.

[0137] In some embodiments, after obtaining the magnet layer and the spin-orbit torque layer, the method further includes:

[0138] Forming a top electrode material layer on the magnet layer;

[0139] Etching the top electrode material layer to obtain a top electrode layer located on the magnet layer;

[0140] Wherein, the external voltage is a voltage in the vertical direction, the voltage in the vertical direction is applied to the top electrode layer, and the vertical direction is the perpendicular direction of the magnetic tunnel junction layer.

[0141] In this embodiment, a top electrode material layer may also be stacked on the surface of the magnet layer, and the top electrode material layer is used for subsequent etching to form a top electrode layer located on the magnet layer. Etch the top electrode material layer to obtain a top electrode layer located on the magnet layer.

[0142] It should be noted that the embodiments of the method for forming the storage unit have the same inventive concept as the embodiments of the structure of the above storage unit.

[0143] The embodiment of the present application also provides a method for reading and writing data of a storage unit, Figure 12 which is a schematic flowchart of a method for reading and writing data of a storage unit shown according to an exemplary embodiment, as Figure 12 shown, the data reading and writing method includes:

[0144] S201. Apply a first voltage at one end of the spin-orbit torque layer and a second voltage at the other end of the spin-orbit torque layer, and the first voltage is less than the second voltage.

[0145] S203. Write a current to the other end of the spin-orbit torque layer so that the spin-orbit torque layer generates a spin current based on the written current.

[0146] S205. Apply an external voltage so that the spin current tunnels through the insulating layer under the action of the external voltage and enters the free layer to flip the magnetization direction in the free layer to achieve data reading and writing.

[0147] Optionally, in the above step S201, a first voltage may be applied to one end of the spin-orbit torque layer, and a second voltage may be applied to the other end of the spin-orbit torque layer, where the first voltage is less than the second voltage.

[0148] Please continue to refer to Figure 12 , in some embodiments, applying a voltage to the end of the spin-orbit torque layer can be considered as applying a voltage to the bit line BL and the source line SL connected to the spin-orbit torque layer. Exemplarily, one end of the spin-orbit torque layer may correspond to the source line SL or the bit line BL, and the other end of the spin-orbit torque layer may correspond to the bit line BL or the source line SL.

[0149] During data read and write operations, an appropriate second voltage may be applied to the bit line BL, and a released first voltage may be applied to the source line SL, so that a current can be written from the other end of the spin-orbit torque layer. The current written into the spin-orbit torque layer will generate a spin current in the spin-orbit torque layer. At this time, a voltage in the vertical direction is applied above the magnetic tunnel junction layer. Under the action of this voltage in the vertical direction, the spin current tunnels through the insulating layer into the free layer to flip the magnetization direction in the free layer, so that the magnetization directions of the free layer and the reference layer are in a parallel state or an anti-parallel state to achieve the read and write of "1" or "0".

[0150] In other embodiments, a second voltage may also be applied to the source line SL, and a first voltage may be applied to the bit line BL.

[0151] Thus, by applying an external voltage, the external voltage is used to cause the spin current generated by the spin-orbit torque layer to tunnel through the insulating layer into the free layer and flip the magnetization direction in the free layer. Therefore, the external voltage can further control the quantity, speed, etc. of the spin current entering the free layer, making the data read and write speed more controllable and the write cost lower. Since the spin current is generated by the spin-orbit torque layer, it is equivalent to SOT; and under the action of the voltage in the vertical direction, this spin current can tunnel through the insulating layer into the free layer, that is, this spin current can tunnel through the magnetic tunnel junction layer, which is equivalent to spin-transfer torque (Spin-Transfer Torque, STT). That is, the embodiment of the present application is equivalent to combining an SOT device and an STT device.

[0152] It should be noted that the embodiments of the present application do not specifically limit the magnitudes of the first voltage, the second voltage, and the external voltage, which can be set according to actual service requirements. Exemplarily, the external voltage can be a relatively moderate voltage, which can be between the first voltage and the second voltage.

[0153] In an alternative embodiment, the external voltage is a voltage in the vertical direction, and the vertical direction is the perpendicular direction of the magnetic tunnel junction layer. Then, in step S205 above, applying the external voltage to enable the spin current to tunnel through the insulating layer into the free layer under the action of the external voltage to flip the magnetization direction in the free layer to achieve data reading and writing includes:

[0154] Apply the voltage in the vertical direction to the top electrode layer located on the reference layer, so that the spin current tunnels through the insulating layer into the free layer under the action of the voltage in the vertical direction to flip the magnetization direction in the free layer to achieve data reading and writing. Since the voltage in the vertical direction acts on the top electrode layer, the voltage in the vertical direction can give the spin current a bottom-up driving force, enabling the spin current to quickly and accurately tunnel through the insulating layer into the free layer, thereby further controlling the quantity, speed, etc. of the spin current entering the free layer, making the data reading and writing speed more controllable and the writing cost lower.

[0155] The embodiment of the present application further provides a memory, and the memory includes a storage unit as described in any of the above embodiments.

[0156] Those skilled in the art will readily conceive of other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include common general knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and embodiments are only to be regarded as exemplary, and the true scope and spirit of the present application are pointed out by the following claims.

[0157] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A storage unit, characterized in that: include: substrate; A spin-orbit moment layer, an insulating layer and a magnetic tunnel junction layer are sequentially disposed on the substrate, wherein the magnetic tunnel junction layer comprises a stacked free layer, a tunnel layer and a reference layer; The insulating layer is used to reduce the thermal diffusion effect of the spin-orbit moment layer on the free layer when the spin-orbit moment layer is energized; the spin-orbit moment layer is used to generate a spin current, and under the action of an external voltage, tunnels through the insulating layer into the free layer to flip the magnetization direction in the free layer.

2. The storage unit according to claim 1, characterized in that The storage unit further comprises a fixed layer, wherein the fixed layer is located on the reference layer; The fixed layer is used to fix the reference layer, and the direction of the magnetic field in the fixed layer is opposite to the direction of the magnetic field in the reference layer.

3. The storage unit according to claim 2, characterized in that The memory cell further includes a first metal hard mask layer, the first metal hard mask layer being located on the fixed layer; The first metal hard mask layer is used as an etching mask for etching to form the fixed layer, the magnetic tunnel junction layer and the insulating layer.

4. The storage unit according to claim 3, characterized in that The storage unit further includes a magnet layer located on the first metal hard mask layer.

5. The storage unit according to claim 4, characterized in that The memory cell further includes a second metal hard mask layer, the second metal hard mask layer being located on the magnet layer; The second metal hard mask layer is used as an etching mask for etching to form the magnet layer and the spin-orbit moment layer.

6. The storage unit according to any one of claims 1 to 5, characterized in that: The external voltage is a voltage in a vertical direction. The storage unit also includes a top electrode layer, which is located on the reference layer. The voltage in the vertical direction is applied to the top electrode layer, and the vertical direction is a perpendicular direction to the magnetic tunnel junction layer.

7. The storage unit according to claim 1, characterized in that The insulating layer is made of oxide insulating material.

8. The storage unit according to claim 7, characterized in that The oxide insulating material includes one or more of magnesium oxide, silicon oxide, silicon nitride, aluminum oxide, magnesium aluminum oxide, titanium oxide layer, tantalum oxide, calcium oxide and iron oxide.

9. A method for forming a memory cell, characterized in that: The forming method comprises: providing a substrate; forming a spin-orbit moment material layer on the substrate; forming an insulating material layer on the spin-orbit moment material layer; forming a magnetic tunnel junction material layer on the insulating material layer; Sequentially etching the magnetic tunnel junction material layer, the insulating material layer and the spin-orbit moment material layer to form the magnetic tunnel junction layer, the insulating layer and the spin-orbit moment layer; The insulating layer is used to reduce the thermal diffusion effect of the spin-orbit moment layer on the free layer when the spin-orbit moment layer is energized; the spin-orbit moment layer is used to generate a spin current, and under the action of an external voltage, tunnels through the insulating layer into the free layer to flip the magnetization direction in the free layer.

10. The method for forming a memory cell according to claim 9, wherein: After forming the magnetic tunnel junction layer, the insulating layer and the spin-orbit moment layer, the method further includes: forming a top electrode material layer on the magnetic tunnel junction layer; Etching the top electrode material layer to obtain a top electrode layer located on the magnetic tunnel junction layer; The external voltage is a voltage in a vertical direction, the voltage in the vertical direction is applied to the top electrode layer, and the vertical direction is a direction perpendicular to the magnetic tunnel junction layer.

11. The method for forming a memory cell according to claim 9, wherein: After forming a magnetic tunnel junction material layer on the insulating material layer, the method further comprises: forming a first metal hard mask layer on the magnetic tunnel junction material layer; The step of sequentially etching the magnetic tunnel junction material layer, the insulating material layer and the spin-orbit moment material layer to form the magnetic tunnel junction layer, the insulating layer and the spin-orbit moment layer comprises: Sequentially etching the first metal hard mask layer, the magnetic tunnel junction material layer, and the insulating material layer until a surface of the spin-orbit moment layer is exposed to form the magnetic tunnel junction layer and the insulating layer; forming a second metal hard mask layer on the magnetic tunnel junction layer; The second metal hard mask layer and the spin-orbit moment layer are sequentially etched until a surface of the substrate is exposed to obtain the spin-orbit moment layer.

12. The method for forming a memory cell according to claim 9, wherein: After forming a magnetic tunnel junction material layer on the insulating material layer, the method further comprises: forming a fixed material layer on the magnetic tunnel junction material layer; forming a first metal hard mask layer on the fixed material layer; The step of sequentially etching the magnetic tunnel junction material layer, the insulating material layer and the spin-orbit moment material layer to form the magnetic tunnel junction layer, the insulating layer and the spin-orbit moment layer comprises: The first metal hard mask layer, the fixed material layer, the magnetic tunnel junction material layer and the insulating material layer are sequentially etched until the surface of the spin-orbit moment layer is exposed to form a fixed layer, the magnetic tunnel junction layer and the insulating layer; the fixed layer is used to fix the reference layer, and the direction of the magnetic field in the fixed layer is opposite to the direction of the magnetic field in the reference layer; forming a magnetic material layer on the first metal hard mask layer; forming a second metal hard mask layer on the magnetic material layer; The second metal hard mask layer, the magnet material layer and the spin-orbit moment material layer are sequentially etched until the surface of the substrate is exposed, thereby obtaining the magnet layer and the spin-orbit moment layer.

13. The method for forming a memory cell according to claim 12, wherein: After obtaining the magnet layer and the spin-orbit moment layer, the method further comprises: forming a top electrode material layer on the magnet layer; Etching the top electrode material layer to obtain a top electrode layer located on the magnet layer; The external voltage is a voltage in a vertical direction, the voltage in the vertical direction is applied to the top electrode layer, and the vertical direction is a direction perpendicular to the magnetic tunnel junction layer.

14. The method for forming a memory cell according to any one of claims 9 to 13, characterized in that: The insulating layer is made of oxide insulating material, and the oxide insulating material includes one or more of magnesium oxide, silicon oxide, silicon nitride, aluminum oxide, magnesium aluminum oxide, titanium oxide layer, tantalum oxide, calcium oxide and iron oxide.

15. A method for reading and writing data in a storage unit according to any one of claims 1 to 8, characterized in that: The data reading and writing method comprises: Applying a first voltage to one end of the spin-orbit moment layer and a second voltage to the other end of the spin-orbit moment layer, wherein the first voltage is less than the second voltage; Writing a current to the other end of the spin-orbit moment layer so that the spin-orbit moment layer generates a spin current based on the written current; An external voltage is applied so that the spin current tunnels through the insulating layer into the free layer under the action of the external voltage to flip the magnetization direction in the free layer to achieve data reading and writing.

16. The data reading and writing method according to claim 15, characterized in that: The external voltage is a voltage in a vertical direction, the vertical direction is a perpendicular direction of the magnetic tunnel junction layer, and the external voltage is applied so that the spin current tunnels through the insulating layer into the free layer under the action of the external voltage to flip the magnetization direction in the free layer to realize data reading and writing, including: The vertical voltage is applied to the top electrode layer located on the reference layer, so that the spin current tunnels through the insulating layer into the free layer under the action of the vertical voltage to flip the magnetization direction in the free layer to realize data reading and writing.

17. A memory, characterized in that: The memory comprises the storage unit according to any one of claims 1 to 8.

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