Magnetic random access memory and preparation method thereof

Abstract

The invention provides a magnetic random access memory and a preparation method thereof. The magnetic random access memory is applied to a comparison circuit, and comprises a magnetic tunnel junction comprising a free layer, a barrier layer and a reference layer which are stacked in sequence; the spin-orbit torque layer is located on the side, away from the reference layer, of the free layer, the conductive material layer is located on the side, away from the spin-orbit torque layer, of the magnetic tunnel junction, and a conductive material of the conductive material layer has the following characteristics that spontaneous magnetization capacity is achieved, and the resistance temperature coefficient is smaller than 0; the conductive material layer comprises a first part and a second part which are arranged at an interval, the first part is in contact with the reference layer, a first input end of the comparison circuit is electrically connected with the first part, and a second input end of the comparison circuit is electrically connected with the second part. According to the invention, the technical problems that the reading window of the magnetic tunnel junction becomes small and even the reading is wrong and the magnetic random access memory needs to apply an auxiliary magnetic field along the current direction to realize the deterministic overturning of the magnetic moment are at least solved.

Description

Technical Field

[0001] This invention relates to the field of memory technology, and more specifically, to a magnetic random access memory, a method for preparing the magnetic random access memory, and a memory read circuit. Background Technology

[0002] Spin-orbit-Torque Magnetic Random Access Memory (SOT-MRAM) features high speed, low power consumption, and high reliability, making it a promising application. The storage cell of SOT-MRAM consists of a spin-orbit torque layer (SOT orbital layer) providing the spin-orbit torque (SOT) and a magnetic tunnel junction (MTJ). The magnetic moment direction of the free layer in the MTJ can be changed by a magnetic field or current. When the magnetic moments of the free layers and the reference layer on both sides of the barrier layer are aligned in parallel, the storage cell exhibits a low-resistance state (R0). P When the magnetic moments of the free layers and the reference layer on both sides of the barrier layer are antiparallel, the memory cell exhibits a high-resistivity state (R0). AP) The low-resistance state and high-resistance state of a storage cell can correspond to data 0 or 1, respectively.

[0003] Reading data from a SOT-MRAM memory cell typically requires a reference resistor R. Ref That is, by comparing the resistance of the memory cell with the reference resistance R. Ref The size of the value determines whether the data in the memory cell is 0 or 1. Because fixed resistors have good stability, existing technologies generally use them as reference resistors. However, fixed resistors are not only greatly affected by process variations, but also exhibit a characteristic of increasing resistance with increasing temperature. Furthermore, when the magnetic moments of the MTJ free layer and the reference layer are antiparallel, R... AP The resistance decreases as the temperature rises, which can further reduce the read window or even lead to read errors.

[0004] In addition, when writing data, vertical SOT-MRAM still faces technical challenges in zero magnetic field reversal, requiring the application of an auxiliary magnetic field along the current direction to achieve deterministic reversal of the magnetic moment.

[0005] Therefore, a new type of magnetic random access memory is urgently needed to at least address the issue of the high resistance state (R) exhibited by magnetic tunnel junctions. AP The resistance of SOT-MRAM decreases as the temperature rises, which leads to a smaller read window and even read errors. There are also technical problems with vertical SOT-MRAM, which require an auxiliary magnetic field to be applied along the current direction to achieve deterministic reversal of the magnetic moment. Summary of the Invention

[0006] The main objective of this invention is to provide a magnetic random access memory, a method for fabricating a magnetic random access memory, and a memory read circuit, so as to at least solve the problem of high resistance states (R0) in magnetic tunnel junctions in the prior art. AP The resistance of SOT-MRAM decreases as the temperature rises, which leads to a smaller read window and even read errors. There are also technical problems with vertical SOT-MRAM, which require an auxiliary magnetic field to be applied along the current direction to achieve deterministic reversal of the magnetic moment.

[0007] To achieve the above objectives, according to one aspect of the present invention, a magnetic random access memory (RAM) is provided for use in a comparator circuit. The RAM includes: a magnetic tunnel junction comprising a free layer, a barrier layer, and a reference layer sequentially stacked, wherein the magnetization directions of the free layer and the reference layer are perpendicular to the stacking direction; a spin-orbit torque layer located on the side of the free layer away from the reference layer; and a conductive material layer located on the side of the magnetic tunnel junction away from the spin-orbit torque layer, wherein the conductive material of the conductive material layer has the following characteristics: spontaneous magnetization capability and a temperature coefficient of resistance less than 0; wherein the conductive material layer includes a first portion and a second portion spaced apart, the first portion being in contact with the reference layer, a first input terminal of the comparator circuit being electrically connected to the first portion, and a second input terminal of the comparator circuit being electrically connected to the second portion.

[0008] Optionally, the second part includes a first conductive part and at least one second conductive part connected in series.

[0009] Optionally, the conductive material layer is a magnetic semiconductor layer.

[0010] Optionally, the material of the magnetic semiconductor layer includes a magnetic material containing doped atoms, which are used to control the temperature coefficient of resistance and sheet resistance of the magnetic material.

[0011] Optionally, the temperature coefficient of resistance after adjusting the magnetic material is -400 to -1000 ppm / ℃.

[0012] Optionally, the sheet resistance after adjusting the magnetic material is 20-50 Ω / Sq.

[0013] Optionally, the conductive material layer includes a first conductive layer and a second conductive layer stacked together, wherein the conductive material of the first conductive layer has at least spontaneous magnetization capability, and the temperature coefficient of resistance of the material of the second conductive layer is less than 0.

[0014] Optionally, the material of the second conductive layer includes any one of tantalum nitride, a semiconductor material with metal-insulator transition properties, and a topological insulator material.

[0015] Optionally, the doping atoms include any one of silicon, phosphorus, and boron.

[0016] Optionally, the magnetic material of the first conductive layer includes at least one of iron, nickel-iron, cobalt, cobalt-iron, cobalt-iron-boron, zinc-manganese alloy, and cobalt-manganese alloy.

[0017] According to another aspect of the present invention, a method for fabricating a magnetic random access memory (RAM) is provided, comprising: providing a semiconductor substrate; forming a spin-orbit torque layer on one side of the semiconductor substrate; forming a magnetic tunnel junction on the side of the spin-orbit torque layer away from the semiconductor substrate, the magnetic tunnel junction comprising a free layer, a barrier layer, and a reference layer sequentially stacked, wherein the spin-orbit torque layer is located on the side of the free layer away from the reference layer, and the magnetization directions of the free layer and the reference layer are perpendicular to the stacking direction; forming a conductive material layer on the side of the magnetic tunnel junction away from the spin-orbit torque layer, the conductive material layer comprising a first portion and a second portion spaced apart, wherein the first portion is in contact with the reference layer, the first portion is electrically connected to a first input terminal of a comparator circuit, the second portion is electrically connected to a second input terminal of the comparator circuit, and the conductive material of the conductive material layer has the following characteristics: spontaneous magnetization capability and a temperature coefficient of resistance less than 0.

[0018] Optionally, the step of forming a conductive material layer includes: setting a photomask on the side of the conductive material away from the magnetic tunnel junction, the photomask having a first cutout region and a second cutout region spaced apart; performing photolithography and etching on the conductive material using the photomask to fill the first cutout region and the second cutout region with the remaining conductive material; wherein, the photomask is removed so that the conductive material corresponding to the first cutout region constitutes a first part, and the conductive material corresponding to the second cutout region constitutes a second part.

[0019] According to another aspect of the present invention, a memory read circuit is provided, comprising: a comparison circuit having a first input terminal and a second input terminal; a magnetic random access memory as described above, or a magnetic random access memory formed by the above-described preparation method, wherein a first part of the magnetic random access memory is electrically connected to the first input terminal, a second part of the magnetic random access memory is electrically connected to the second input terminal, and the comparison circuit is used to read data of a magnetic tunnel junction based on input data from the first input terminal and the second input terminal.

[0020] The present invention provides a magnetic random access memory (MRM), comprising a magnetic tunnel junction, a spin-orbit torque layer, and a conductive material layer. The magnetic tunnel junction comprises a free layer, a barrier layer, and a reference layer sequentially stacked. The spin-orbit torque layer is located on the side of the free layer away from the reference layer, and the conductive material layer is located on the side of the magnetic tunnel junction away from the spin-orbit torque layer. Further, the conductive material layer comprises a first portion and a second portion spaced apart, with the first portion contacting the reference layer. When this MRM is applied in a comparator circuit, since the first portion is in contact with the reference layer, when the magnetic tunnel junction is a storage cell in the MRM, the storage cell in the MRM may also include the first portion. That is, the first portion of the conductive material layer serves as a part of the storage cell in the MRM and is electrically connected to the first input terminal of the comparator circuit. The second portion of the conductive material layer is spaced apart from the first portion and serves as a reference resistor for the MRM, electrically connected to the second input terminal of the comparator circuit. Furthermore, since the second part is part of the conductive material layer, and the temperature coefficient of resistance of the corresponding conductive material is less than 0, meaning the resistance of the second part decreases with increasing temperature, even when the magnetic moments of the free layer and the reference layer are antiparallel, the magnetic tunnel junction exhibits a high resistance state (R0). AP When the resistance of the magnetic tunnel junction decreases with increasing temperature, the read window of the magnetic random access memory does not shrink, thus solving the problem of the high resistance state (R) of the magnetic tunnel junction in the prior art. AP The resistance of the magnetic random access memory (SOT-MRAM) decreases with increasing temperature, leading to a smaller read window and even read errors. Furthermore, when the first part is part of a memory cell (the direction in which the magnetization directions of the free layer and the reference layer of the magnetic tunnel junction are stacked perpendicularly) in the magnetic random access memory, this first part, as part of the conductive material layer, can generate a stray field to assist the spin-orbit torque layer in achieving SOT flipping due to the spontaneous magnetization capability of its conductive material. This allows the vertical SOT-MRAM to achieve deterministic flipping of the magnetic moment without applying an auxiliary magnetic field along the current direction, solving the technical problem in the prior art where a deterministic flipping of the magnetic moment in vertical SOT-MRAM requires an auxiliary magnetic field along the current direction. In addition, in this application, the first part and the second part serve as the conductive material layer of the magnetic random access memory, eliminating the need for additional steps to form the first part and the second part respectively. Therefore, when the magnetic random access memory is applied in a comparison circuit, the first part serves as one part of the memory cell of the magnetic random access memory, and the second part serves as the reference resistor of the magnetic random access memory, making the fabrication of the memory cell and the reference resistor compatible, thereby simplifying the structure of the magnetic random access memory. Attached Figure Description

[0021] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 A schematic diagram of the structure of a magnetic random access memory according to an embodiment of the present invention is shown;

[0023] Figure 2 A schematic diagram of a comparator circuit including the aforementioned magnetic random access memory is shown;

[0024] Figure 3 A schematic diagram of the resistance banding in the second part of a magnetic random access memory according to an embodiment of the present invention is shown.

[0025] Figure 4 It shows Figure 2 The diagram shows another type of magnetic random access memory based on the above.

[0026] The above figures include the following reference numerals:

[0027] 100, Memory cell; 10, Magnetic tunnel junction; 101, Free layer; 102, Barrier layer; 103, Reference layer; 20, Spin-orbit torque layer; 30, Conductive material layer; 300, Amplifier; 301, First part; 302, Second part; 3021, First conductive part; 3022, Second conductive part; 310, First conductive layer; 320, Second conductive layer; 40, Spacer layer; 50, Conductive channel; 60, Metal interconnect layer; 70, Switching device. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] As described in the background section, existing technologies generally utilize fixed resistors as reference resistors for magnetic random access memories (MRJs). However, fixed resistors are not only highly susceptible to process variations but also exhibit an increasing resistance with rising temperature. Furthermore, when the magnetic moments of the MTJ free layer and the reference layer are antiparallel, R... AP The resistance decreases with increasing temperature, further reducing the read window and potentially leading to read errors. Furthermore, during data writing, vertical SOT-MRAM faces technical challenges in achieving zero-magnetic-field switching of the SOT orbital layer, requiring the application of an auxiliary magnetic field along the current direction to achieve deterministic switching of the magnetic moment. Therefore, a new magnetic random access memory is urgently needed to address at least the following two technical problems of existing vertical SOT-MRAM magnetic random access memories: the magnetic tunnel junction exhibits a high-resistivity state (R0). AP When the temperature rises, the resistance decreases, and the read window becomes smaller or even reads incorrectly. Vertical SOT-MRAM requires an auxiliary magnetic field to be applied along the current direction to achieve deterministic flipping of the magnetic moment.

[0032] To address the aforementioned technical problems, this application provides a magnetic random access memory, such as... Figure 1 As shown, the magnetic random access memory (RAM) used in a comparator circuit includes: a magnetic tunnel junction 10, comprising a free layer 101, a barrier layer 102, and a reference layer 103 stacked sequentially, with the magnetization directions of the free layer 101 and the reference layer 103 perpendicular to the stacking direction; a spin-orbit torque layer 20 located on the side of the free layer 101 away from the reference layer 103; and a conductive material layer 30 located on the side of the magnetic tunnel junction 10 away from the spin-orbit torque layer 20, wherein the conductive material of the conductive material layer 30 has the following characteristics: spontaneous magnetization capability and a temperature coefficient of resistance less than 0; wherein the conductive material layer 30 includes a first portion and a second portion spaced apart, and the first portion is in contact with the reference layer 103, the first input terminal of the comparator circuit is electrically connected to the first portion, and the second input terminal of the comparator circuit is electrically connected to the second portion.

[0033] In some exemplary embodiments, the positional relationship between the magnetic tunnel junction 10 and the first portion can be: the first portion is located on the side of the reference layer 103 away from the free layer 101 of the magnetic tunnel junction 10, and is in direct contact with the reference layer 103, i.e., the first portion is in direct contact with the reference layer 103; in other exemplary embodiments, such as... Figure 1 As shown in (a), the magnetic random access memory may further include a conductive spacer layer 40, and the positional relationship between the magnetic tunnel junction 10, the first part and the spacer layer 40 may be as follows: the first part is located on the side of the reference layer 103 away from the free layer 101, the spacer layer 40 is located between the reference layer 103 and the first part, and the spacer layer 40 is in direct contact with the reference layer 103 and the first part respectively, so that the reference layer 103 and the first part are in indirect contact.

[0034] Optionally, the first portion of the magnetic tunnel junction 10, the spin-orbit torque layer 20, and the conductive material layer 30 can serve as storage units of the magnetic random access memory, such as... Figure 1 As shown in (a), the first part can be the electrode layer of the magnetic tunnel junction 10, and the second part of the conductive material layer 30 can serve as the reference resistor of the magnetic random access memory, such as... Figure 1 As shown in (b). Thus, when this magnetic random access memory is used in a comparator circuit for data reading, the first part can be electrically connected to the first input terminal of the comparator circuit, and the second part can be electrically connected to the second input terminal of the comparator circuit. Optionally, the resistance of the reference resistor is such that the magnetic tunnel junction 10 exhibits a high resistance state (R). AP The resistance and magnetic tunnel junction 10 exhibit a low resistance state (R) at this time. P The resistance is half of the sum of the values ​​of the magnetic tunnel junction 10. The conductive material of the conductive material layer 30 exhibits magnetism, and the temperature coefficient of resistance of the conductive material is close to the high resistance state (R) of the magnetic tunnel junction 10. AP The temperature coefficient is 50% of the value at that time.

[0035] Optionally, the sheet resistance R of the conductive material corresponding to the first and second portions of the conductive material layer 30 is... s All are 20-50Ω / Sq.

[0036] Optionally, to save area of ​​the magnetic random access memory, the second part of the conductive material layer 30 can be composed of bent lines of a certain total length L, where L≈(R P +R AP ) / 2R s .

[0037] In the above embodiments, when the magnetic random access memory (MRMemory) is applied in a comparator circuit, since the first part is in contact with the reference layer, and the magnetic tunnel junction is used as a storage cell in the MRMemory, the storage cell in the MRMemory can also include the first part. That is, the first part of the conductive material layer serves as a part of the storage cell in the MRMemory and is electrically connected to the first input terminal of the comparator circuit. The second part of the conductive material layer is spaced apart from the first part and serves as the reference resistor of the MRMemory, and is electrically connected to the second input terminal of the comparator circuit. Furthermore, since the second part is a part of the conductive material layer, the temperature coefficient of resistance of the corresponding conductive material is less than 0, that is, the resistance of the second part decreases with increasing temperature. Therefore, even when the magnetic moments of the free layer and the reference layer are antiparallel, the MRMemory exhibits a high resistance state (R0). AP When the resistance of the magnetic tunnel junction decreases with increasing temperature, the read window of the magnetic random access memory does not shrink, thus solving the problem of the high resistance state (R) of the magnetic tunnel junction in the prior art. AP The resistance of the magnetic random access memory (SOT-MRAM) decreases with increasing temperature, leading to a smaller read window and even read errors. Furthermore, when the first part is part of a memory cell (the direction in which the magnetization directions of the free layer and the reference layer of the magnetic tunnel junction are stacked perpendicularly) in the magnetic random access memory, this first part, as part of the conductive material layer, can generate a stray field to assist the spin-orbit torque layer in achieving SOT flipping due to the spontaneous magnetization capability of its conductive material. This allows the vertical SOT-MRAM to achieve deterministic flipping of the magnetic moment without applying an auxiliary magnetic field along the current direction, solving the technical problem in the prior art where a deterministic flipping of the magnetic moment in vertical SOT-MRAM requires an auxiliary magnetic field along the current direction. In addition, in this application, the first part and the second part serve as the conductive material layer of the magnetic random access memory, eliminating the need for additional steps to form the first part and the second part respectively. Therefore, when the magnetic random access memory is applied in a comparison circuit, the first part serves as one part of the memory cell of the magnetic random access memory, and the second part serves as the reference resistor of the magnetic random access memory, making the fabrication of the memory cell and the reference resistor compatible, thereby simplifying the structure of the magnetic random access memory.

[0038] In some alternative embodiments, the magnetic random access memory may further include a metal interconnect layer 60, which may be located on the side of the conductive material layer 30 away from the magnetic tunnel junction 10, such as... Figure 1As shown in (b), the second portion of the conductive material layer 30 is electrically connected to the second input terminal of the comparator circuit (not shown) via the conductive channel 50 and the metal interconnect layer 60. It is understood that the first portion of the conductive material layer 30 can also be electrically connected to the first input terminal of the comparator circuit (not shown) via the conductive channel (not shown) and the metal interconnect layer (not shown).

[0039] Optionally, such as Figure 2 As shown, when the above-mentioned magnetic random access memory is applied to a comparison circuit, the comparison circuit may also include an amplifier 300 and control transistors S1 and S2. The memory cell 100 (including the first part 301) is electrically connected to the first input terminal of the amplifier 300 and also electrically connected to the control transistor S1. The reference resistor (the second part 302) is electrically connected to the second input terminal of the amplifier 300 and also electrically connected to the control transistor S2.

[0040] The second portion of the conductive material layer serves as a reference resistor for the magnetic random access memory. To facilitate adjustment of the resistance value of this reference resistor, in some optional embodiments, such as... Figure 3 As shown, the second part includes a first conductive part 3021 and at least one second conductive part 3022 connected in series. That is, each of the first conductive part 3021 and each of the second conductive parts 3022 can be a sub-reference resistor, and multiple sub-reference resistors connected in series constitute the reference resistor of the magnetic random access memory. Furthermore, the resistance of the first conductive part 3021 is greater than the resistance of the second conductive part 3022. Therefore, with the resistance of the first conductive part 3021 fixed, the second conductive part 3022 can be used to precisely adjust the reference resistor of the magnetic random access memory, thereby increasing the detection accuracy of the magnetic random access memory.

[0041] Specifically, the conductive material layer includes a first portion in contact with the reference layer, a first conductive portion 3021 spaced apart from the first portion, and at least one second conductive portion 3022 spaced apart from the first portion, wherein the first conductive portion 3021 and at least one second conductive portion 3022 are connected in series. It should be noted that the first conductive portion 3021 and any one of the second conductive portions 3022 are spaced apart, and any two second conductive portions 3022 are spaced apart.

[0042] Optionally, when a memory device including the first conductive portion 3021 and at least one second conductive portion 3022 is applied to a comparison circuit, the comparison circuit may include a current-sensitive amplifier, a decoder, and at least one switching device 70. The first terminal of each switching device 70 is electrically connected to the first input terminal of the current-sensitive amplifier, and the second terminal of each switching device 70 is electrically connected to a second conductive portion 3022. The control terminal of each switching device 70 is electrically connected to the decoder. Figure 3 As shown, when the first conductive part 3021 and at least one second conductive part 3022 are connected in series, at least one switching device 70 corresponds one-to-one with at least one second conductive part 3022. By controlling the opening or closing of each switching device 70, the number of second conductive parts 3022 connected to the comparator circuit can be controlled, thereby dividing the resistance value corresponding to the second part into different ranges and achieving the purpose of adjusting the resistance value of the reference resistor. For example, the switching device 70 can be a MOSFET.

[0043] For example, the sheet resistance R of the first conductive part 3021 and the second conductive part 3022 described above... s It can be 20-50Ω / Sq. Furthermore, in order to form a reference resistance adjustment of <100Ω per range, the aforementioned second conductive part 3022 can be a unit resistor with a resistance value of 50 to 100Ω formed by layout.

[0044] In order to ensure that the conductive material layer of the magnetic random access memory in this application can solve the problem of the high resistance state (R) of the magnetic tunnel junction in the prior art, AP The resistance of the magnetic field decreases as the temperature rises, which further leads to a smaller read window or even read errors. This can also solve the technical problem that vertical SOT-MRAM in the prior art requires an auxiliary magnetic field to be applied along the current direction to achieve deterministic reversal of the magnetic moment. In some optional embodiments, the conductive material layer is a magnetic semiconductor layer.

[0045] Optionally, the material of the aforementioned magnetic semiconductor layer may include, but is not limited to, magnetic materials containing doped atoms, which are used to control the temperature coefficient of resistance and sheet resistance of the magnetic material.

[0046] Specifically, the doped atoms mentioned above can include, but are not limited to, any one of silicon, phosphorus, and boron. Magnetic materials containing doped atoms can include, but are not limited to, at least one of iron, nickel-iron, cobalt, cobalt-iron, cobalt-iron-boron, zinc-manganese alloys, and cobalt-manganese alloys. This application does not specifically limit the magnetic materials containing doped atoms; those skilled in the art can reasonably select the doped atoms and magnetic materials according to actual needs.

[0047] For example, the magnetic material obtained by controlling the magnetic material with the aforementioned doping atoms is the conductive material of the magnetic semiconductor layer. Based on this, the temperature coefficient of resistance after controlling the magnetic material is the temperature coefficient of resistance of the conductive material of the magnetic semiconductor layer, which can be -400 to -1000 ppm / ℃. Similarly, the sheet resistance after controlling the magnetic material is the sheet resistance of the conductive material of the magnetic semiconductor layer, which can be 20-50 Ω / sq.

[0048] For example, when the conductive material layer is a magnetic semiconductor layer, the reference layer of the magnetic tunnel junction in the magnetic random access memory is in indirect contact with the first part of the conductive material layer, that is, there is the aforementioned spacer layer between the reference layer and the first part. The spacer layer is used to isolate the magnetic semiconductor layer and the reference layer to avoid magnetic interference between the magnetic semiconductor layer and the reference layer.

[0049] Optionally, the resistance of the conductive material changes with temperature according to the following relationship: R = R0(T) cr ×(t-25))+1), where t is the temperature, T cr R is the temperature coefficient of resistance of the conductive material, R0 is the resistance of the conductive material at room temperature, and R is the resistance of the conductive material at temperature t.

[0050] In some alternative implementations, in Figure 1 On the basis of, such as Figure 4 As shown, two different conductive materials can also be combined to give the conductive material layer 30 of the magnetic random access memory the aforementioned spontaneous magnetization capability and temperature coefficient of resistance less than 0. Specifically, the conductive material layer 30 includes a first conductive layer 310 and a second conductive layer 320 stacked together. The conductive material of the first conductive layer 310 has at least the aforementioned spontaneous magnetization capability, and the material of the second conductive layer 320 has a temperature coefficient of resistance less than 0. It should be noted that the positional relationship of the first conductive layer 310 and the second conductive layer 320 relative to the magnetic tunnel junction 10 can be interchanged. In some optional embodiments, the first conductive layer 310 is closer to the magnetic tunnel junction 10 than the second conductive layer 320, while the second conductive layer 320 is farther away from the magnetic tunnel junction 10 than the first conductive layer 310; or in other optional embodiments, the first conductive layer 310 is farther away from the magnetic tunnel junction 10 than the second conductive layer 320, while the second conductive layer 320 is closer to the magnetic tunnel junction 10 than the first conductive layer 310.

[0051] For example, the magnetic material of the first conductive layer 310 may include, but is not limited to, at least one of iron, nickel-iron, cobalt, cobalt-iron, cobalt-iron-boron, zinc-manganese alloy, and cobalt-manganese alloy. The material of the second conductive layer 320 may include, but is not limited to, any one of tantalum nitride, semiconductor materials with metal-insulator transition properties, and topological insulator materials.

[0052] According to another aspect of this application, a method for fabricating a magnetic random access memory (RAM) is provided, comprising: providing a semiconductor substrate; forming a spin-orbit torque layer on one side of the semiconductor substrate; forming a magnetic tunnel junction on the side of the spin-orbit torque layer away from the semiconductor substrate, the magnetic tunnel junction comprising a free layer, a barrier layer, and a reference layer sequentially stacked, wherein the spin-orbit torque layer is located on the side of the free layer away from the reference layer, and the magnetization directions of the free layer and the reference layer are perpendicular to the stacking direction; forming a conductive material layer on the side of the magnetic tunnel junction away from the spin-orbit torque layer, the conductive material layer comprising a first portion and a second portion spaced apart, wherein the first portion is in contact with the reference layer, the first portion is electrically connected to a first input terminal of a comparator circuit, the second portion is electrically connected to a second input terminal of the comparator circuit, and the conductive material of the conductive material layer has the following characteristics: spontaneous magnetization capability and a temperature coefficient of resistance less than 0.

[0053] In the above embodiments, the first and second portions of the conductive material layer are formed in the same process step. Therefore, the conductive materials of the first and second portions are the same. Furthermore, since this conductive material simultaneously possesses spontaneous magnetization capability and a temperature coefficient of resistance less than 0, the magnetic random access memory of this application can at least solve the problem of high resistance states (R0) in magnetic tunnel junctions in the prior art. AP The technical problem is that the resistance of SOT-MRAM decreases with increasing temperature, which further leads to a smaller read window or even read errors. It also addresses the technical problem that vertical SOT-MRAM requires an auxiliary magnetic field to be applied along the current direction to achieve deterministic reversal of the magnetic moment.

[0054] In some optional embodiments, in order to simplify the structure of the magnetic random access memory (MRM) and to make the conductive material layer of the MLM simultaneously possess spontaneous magnetization capability and a temperature coefficient of resistance of less than 0, the step of forming the conductive material layer includes: setting a photomask on the side of the conductive material away from the magnetic tunnel junction, the photomask having a first cutout region and a second cutout region spaced apart; performing photolithography and etching on the conductive material using the photomask to fill the first cutout region and the second cutout region with the remaining conductive material; wherein, the photomask is removed so that the conductive material corresponding to the first cutout region constitutes the first part, and the conductive material corresponding to the second cutout region constitutes the second part.

[0055] According to another aspect of this application, this application also provides a memory read circuit, comprising: a comparison circuit having a first input terminal and a second input terminal; a magnetic random access memory as described above, or a magnetic random access memory formed by the above-described preparation method, wherein a first portion of the magnetic random access memory is electrically connected to the first input terminal, a second portion of the magnetic random access memory is electrically connected to the second input terminal, and the comparison circuit is used to read data from the magnetic tunnel junction based on input data from the first input terminal and the second input terminal.

[0056] Specifically, the comparator circuit is used to determine the resistance value of the memory cell of the magnetic random access memory and the resistance value of the reference resistor of the magnetic random access memory based on the input data of the first input terminal and the second input terminal. Then, based on the relationship between the resistance value of the memory cell and the resistance value of the reference resistor, it determines that the memory cell operates in a low-resistance state (R0). P ) or exhibits a high resistance state (R) AP Specifically, when the resistance values ​​of the memory cell and the reference resistor are similar, the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are aligned in parallel, and the memory cell operates in a low-resistance state (R0). P When the resistance of the magnetic tunnel junction differs significantly from that of the reference resistor, the magnetic moments of the free layer and the reference layer of the magnetic tunnel junction are antiparallel, and the memory cell operates in a high-resistance state (R0). AP ).

[0057] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0058] The magnetic random access memory (RAM) provided in this application includes a magnetic tunnel junction, a spin-orbit torque layer, and a conductive material layer. The magnetic tunnel junction comprises a free layer, a barrier layer, and a reference layer stacked sequentially. The spin-orbit torque layer is located on the side of the free layer away from the reference layer, and the conductive material layer is located on the side of the magnetic tunnel junction away from the spin-orbit torque layer. Further, the conductive material layer includes a first portion and a second portion spaced apart, with the first portion contacting the reference layer. When this RAM is applied in a comparator circuit, since the first portion is in contact with the reference layer, when the magnetic tunnel junction serves as a storage cell in the RAM, the storage cell in the RAM may also include the first portion. That is, the first portion of the conductive material layer serves as a part of the storage cell in the RAM and is electrically connected to the first input terminal of the comparator circuit, while the second portion of the conductive material layer, spaced apart from the first portion, serves as a reference resistor for the RAM and is electrically connected to the second input terminal of the comparator circuit. Furthermore, since the second part is part of the conductive material layer, and the temperature coefficient of resistance of the corresponding conductive material is less than 0, meaning the resistance of the second part decreases with increasing temperature, even when the magnetic moments of the free layer and the reference layer are antiparallel, the magnetic tunnel junction exhibits a high resistance state (R0). AP When the resistance of the magnetic tunnel junction decreases with increasing temperature, the read window of the magnetic random access memory does not shrink, thus solving the problem of the high resistance state (R) of the magnetic tunnel junction in the prior art. AP The resistance of the magnetic random access memory (SOT-MRAM) decreases with increasing temperature, leading to a smaller read window and even read errors. Furthermore, when the first part is part of a memory cell (the direction in which the magnetization directions of the free layer and the reference layer of the magnetic tunnel junction are stacked perpendicularly) in the magnetic random access memory, this first part, as part of the conductive material layer, can generate a stray field to assist the spin-orbit torque layer in achieving SOT flipping due to the spontaneous magnetization capability of its conductive material. This allows the vertical SOT-MRAM to achieve deterministic flipping of the magnetic moment without applying an auxiliary magnetic field along the current direction, solving the technical problem in the prior art where a deterministic flipping of the magnetic moment in vertical SOT-MRAM requires an auxiliary magnetic field along the current direction. In addition, in this application, the first part and the second part serve as the conductive material layer of the magnetic random access memory, eliminating the need for additional steps to form the first part and the second part respectively. Therefore, when the magnetic random access memory is applied in a comparison circuit, the first part serves as one part of the memory cell of the magnetic random access memory, and the second part serves as the reference resistor of the magnetic random access memory, making the fabrication of the memory cell and the reference resistor compatible, thereby simplifying the structure of the magnetic random access memory.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A magnetic random access memory, characterized in that, The magnetic random access memory, used in comparator circuits, includes: A magnetic tunnel junction includes a free layer, a barrier layer, and a reference layer stacked sequentially, wherein the magnetization directions of the free layer and the reference layer are perpendicular to the stacking direction; The spin-orbit torque layer is located on the side of the free layer away from the reference layer. A conductive material layer is located on the side of the magnetic tunnel junction away from the spin-orbit torque layer, and the conductive material of the conductive material layer has the following characteristics: spontaneous magnetization capability and a temperature coefficient of resistance of less than 0; wherein, The conductive material layer includes a first portion and a second portion spaced apart, with the first portion in contact with the reference layer, the first input terminal of the comparison circuit being electrically connected to the first portion, and the second input terminal of the comparison circuit being electrically connected to the second portion.

2. The magnetic random access memory according to claim 1, characterized in that, The second part includes a first conductive part and at least one second conductive part connected in series.

3. The magnetic random access memory according to claim 1, characterized in that, The conductive material layer is a magnetic semiconductor layer.

4. The magnetic random access memory according to claim 3, characterized in that, The material of the magnetic semiconductor layer includes a magnetic material containing doped atoms, which are used to control the temperature coefficient of resistance and sheet resistance of the magnetic material.

5. The magnetic random access memory according to claim 4, characterized in that, The temperature coefficient of resistance of the magnetic material after adjustment is -400 to -1000 ppm / ℃.

6. The magnetic random access memory according to claim 4, characterized in that, The sheet resistance of the magnetic material is adjusted to 20-50 Ω / Sq.

7. The magnetic random access memory according to any one of claims 4 to 6, characterized in that, The doped atoms include any one of silicon, phosphorus, and boron.

8. The magnetic random access memory according to claim 1, characterized in that, The conductive material layer includes a first conductive layer and a second conductive layer stacked together. The conductive material of the first conductive layer has at least the self-magnetizing ability, and the temperature coefficient of resistance of the material of the second conductive layer is less than 0.

9. The magnetic random access memory according to claim 8, characterized in that, The material of the second conductive layer includes any one of tantalum nitride, semiconductor materials with metal-insulator transition properties, and topological insulator materials.

10. The magnetic random access memory according to claim 8 or 9, characterized in that, The magnetic material of the first conductive layer includes at least one of iron, nickel iron, cobalt, cobalt iron, cobalt iron boron, zinc manganese alloy, and cobalt manganese alloy.

11. A method for fabricating a magnetic random access memory, characterized in that, include: Provide semiconductor substrates; A spin orbital torque layer is formed on one side of the semiconductor substrate; A magnetic tunnel junction is formed on the side of the spin-orbit torque layer away from the semiconductor substrate. The magnetic tunnel junction includes a free layer, a barrier layer, and a reference layer stacked sequentially. The spin-orbit torque layer is located on the side of the free layer away from the reference layer, and the magnetization directions of the free layer and the reference layer are perpendicular to the stacking direction. A conductive material layer is formed on the side of the magnetic tunnel junction away from the spin-orbit torque layer. The conductive material layer includes a first portion and a second portion spaced apart, with the first portion in contact with the reference layer. The first portion is used to be electrically connected to a first input terminal of the comparator circuit, and the second portion is used to be electrically connected to a second input terminal of the comparator circuit. The conductive material of the conductive material layer has the following characteristics: spontaneous magnetization capability and a temperature coefficient of resistance of less than 0.

12. The preparation method according to claim 11, characterized in that, The steps for forming the conductive material layer include: A conductive material is deposited on the side of the magnetic tunnel junction away from the spin-orbit torque layer; A photomask is disposed on the side of the conductive material away from the magnetic tunnel junction, and the photomask has a first hollow area and a second hollow area disposed at intervals. The conductive material is photolithographically and etched using the photomask to fill the first and second hollow areas with the remaining conductive material; wherein, Remove the photomask so that the conductive material corresponding to the first hollow area constitutes the first part, and the conductive material corresponding to the second hollow area constitutes the second part.

13. A memory read circuit, characterized in that, include: The comparator circuit has a first input terminal and a second input terminal; The magnetic random access memory as described in any one of claims 1 to 10, or the magnetic random access memory prepared by the preparation method as described in claim 11 or 12, wherein, The first part of the magnetic random access memory is electrically connected to the first input terminal, and the second part of the magnetic random access memory is electrically connected to the second input terminal. The comparison circuit is used to read the data of the magnetic tunnel junction based on the input data of the first input terminal and the second input terminal.

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