Antiferromagnetic magnetic memory devices and methods of making the same

Abstract

The application provides a kind of antiferromagnetic magnetic memory device and its preparation method, the device includes ferromagnetic film structure, antiferromagnetic film structure and the tunnel insulating film structure being sandwiched between the ferromagnetic film structure and antiferromagnetic film structure.The device preparation method is: first electrode is prepared on substrate from bottom to top, first ferromagnetic film structure is prepared and is applied external magnetic field, first tunnel insulating film structure is prepared, antiferromagnetic film structure, second tunnel insulating film structure is prepared, second ferromagnetic film structure is prepared and is applied external magnetic field opposite to first ferromagnetic film structure, second electrode is prepared.The application can realize the information writing and reading mode of device size reduction, realize high-density storage, and also has the characteristics of terahertz level high-speed information writing and anti-external magnetic interference of antiferromagnetic body.

Description

Technical Field

[0001] This invention relates to the field of memory chips in integrated circuits, and specifically to an antiferromagnetic memory device and its manufacturing method. Background Technology

[0002] Magnetic Random Access Memory (MRAM) has already found some applications in integrated circuits, but current MRAM is mainly based on ferromagnetic materials for storage and retrieval. Antiferromagnets possess superior characteristics that ferromagnets lack, such as ultra-high information writing speeds at the terahertz level and resistance to external magnetic interference, and are considered the most important spintronic devices for next-generation MRAM.

[0003] Currently, spintronic devices based on antiferromagnets are widely studied as candidate devices for MRAM. These devices typically use spin orbit toquence (SOT) to manipulate the spin electrons of the antiferromagnet to write information, and a Hall bar to detect the anomalous Hall effect (AHE) of the antiferromagnet for reading information. However, SOT writing requires a large SOT channel, and AHE reading usually requires a large Hall bar. Therefore, it is difficult to shrink the device size to below 100 nanometers, meaning that high-density storage is difficult to achieve, and thus, large-scale application in integrated circuits is limited. Summary of the Invention

[0004] To address the problems existing in the above-mentioned background technology, the present invention provides an antiferromagnetic memory device and its manufacturing method, which can realize information writing and reading methods that can reduce the device size. This solution not only fully possesses the ultra-high information writing speed at the terahertz level and the characteristics of antiferromagnets such as resistance to external magnetic interference, but also reduces the size of the device to about 10 nanometers, thereby achieving high-density storage.

[0005] To solve the above-mentioned technical problems, the present invention provides an antiferromagnetic memory device, comprising a ferromagnetic thin film structure, an antiferromagnetic thin film structure, and a tunnel insulating thin film structure sandwiched between the ferromagnetic thin film structure and the antiferromagnetic thin film structure.

[0006] The antiferromagnetic memory device, wherein the ferromagnetic thin film structure, the antiferromagnetic thin film structure, and the tunnel insulating thin film structure can all be any one of the following structures: a single-layer thin film composed of a single material and a multilayer stacked film composed of multiple materials.

[0007] The antiferromagnetic memory device includes: a first ferromagnetic thin film structure, a first tunnel insulating thin film structure disposed on the upper part of the first ferromagnetic thin film structure, an antiferromagnetic thin film structure disposed on the upper part of the first tunnel insulating thin film structure, a second tunnel insulating thin film structure disposed on the upper part of the antiferromagnetic thin film structure, and a second ferromagnetic thin film structure disposed on the upper part of the second tunnel insulating thin film structure; the spin electrons of the first ferromagnetic thin film structure and the second ferromagnetic thin film structure are fixed in opposite directions; the first ferromagnetic thin film structure, the first tunnel insulating thin film structure, the antiferromagnetic thin film structure, the second tunnel insulating thin film structure, and the second ferromagnetic thin film structure can all adopt any structure of a single-layer thin film composed of a single material and a multilayer stacked film composed of multiple materials.

[0008] The antiferromagnetic memory device, wherein: the antiferromagnetic thin film structure is provided with VCMA electrodes on its four sides, the magnetic anisotropy of which can be controlled by applying voltage; the VCMA electrodes can be any one of a multilayer heterostructure composed of different materials or a single structure composed of the same material.

[0009] The antiferromagnetic memory device, wherein: an insulating thin film is provided around the sides of the antiferromagnetic thin film structure; the VCMA electrode can be connected to the outer surface of the insulating thin film by any one of the following connection methods: completely surrounding the outer surface of the insulating thin film, partially surrounding the outer surface of the insulating thin film, or partially contacting the outer surface of the insulating thin film.

[0010] The antiferromagnetic memory device, wherein: the antiferromagnetic thin film structure can be replaced with a ferrimagnetic thin film structure; the ferrimagnetic thin film structure can be any one of a single-layer thin film composed of a single material and a multilayer stacked film composed of multiple materials.

[0011] A method for manufacturing an antiferromagnetic memory device includes the following main steps:

[0012] A first electrode is fabricated on a substrate, and then a first ferromagnetic thin film structure is fabricated on the fabricated first electrode. Next, an external magnetic field is applied to align the spin electrons of the first ferromagnetic thin film structure in any direction. Then, a first tunnel insulating thin film structure is fabricated on the fabricated first ferromagnetic thin film structure. Next, an antiferromagnetic thin film structure is fabricated on the first tunnel insulating thin film structure. Then, a second tunnel insulating thin film structure is fabricated on the antiferromagnetic thin film structure. Next, a second ferromagnetic thin film structure is fabricated on the second tunnel insulating thin film structure. Then, an external magnetic field is applied to align the spin electrons of the second ferromagnetic thin film structure in the opposite direction to the spin electrons of the first ferromagnetic thin film structure. Finally, a second electrode is fabricated on the second ferromagnetic thin film structure.

[0013] The method for manufacturing the antiferromagnetic memory device includes the following main steps:

[0014] (1.1) First, a first electrode and a multilayer thin film structure consisting of a ferromagnetic thin film structure, a tunnel insulating thin film structure and an antiferromagnetic thin film structure are prepared. Then, an antiferromagnetic device is formed by semiconductor etching technology. Finally, an insulating thin film is prepared on the outer surface of the antiferromagnetic device.

[0015] (1.2) Then, an insulating isolation layer is deposited on the part of the antiferromagnetic thin film structure of the antiferromagnetic device where no voltage is required;

[0016] (1.3) Then deposit a sacrificial layer with a different etch selectivity than the insulating isolation layer in step (1.2) at the location where voltage needs to be applied to the antiferromagnetic device. The sacrificial layer can be deposited directly to the required thickness or deposited first to a thickness exceeding the thickness of the antiferromagnetic thin film structure and then etched back to the required thickness. Either of these two deposition methods ensures that the thickness of the etched sacrificial layer is less than or equal to the thickness of the antiferromagnetic thin film structure.

[0017] (1.4) An insulating isolation layer is then deposited on the top and sides of the sacrificial layer obtained in step (1.3);

[0018] (1.5) Then deposit a second electrode material at one end of the ferromagnetic thin film structure to which voltage needs to be applied, and etch the second electrode so that the prepared second electrode and the sacrificial layer in step (1.3) have a non-overlapping part in the top view. Then cover it with an insulating isolation layer and grind it flat.

[0019] (1.6) Then, etch and drill holes above the sacrificial layer that does not overlap with the second electrode in step (1.5) until contact with the sacrificial layer, and etch away the sacrificial layer;

[0020] (1.7) Deposit a VCMA electrode at the location where the sacrificial layer was etched away in step (1.6);

[0021] (1.8) Then etch away the excess VCMA electrode material at the location of the hole in step (1.6) and deposit the external wires connected to the VCMA electrode material to finally form a VCMA electrode that can apply voltage to the antiferromagnetic thin film structure.

[0022] The method for manufacturing the antiferromagnetic memory device, wherein the VCMA electrode may also be prepared according to the following main steps:

[0023] (2.1) Deposit an insulating thin film on the surface of the antiferromagnetic device;

[0024] (2.2) Deposit an insulating layer in the portion of the antiferromagnetic device where no voltage needs to be applied;

[0025] (2.3) Then deposit a VCMA electrode on the outer side of the insulating film corresponding to the side of the antiferromagnetic thin film structure of the antiferromagnetic device; the VCMA electrode can be deposited by directly depositing to the required thickness or depositing to a thickness exceeding the thickness of the antiferromagnetic thin film structure and then etching back to the required thickness, either of these two methods, so that the thickness of the deposited VCMA electrode is less than or equal to the thickness of the antiferromagnetic thin film structure.

[0026] (2.4) The VCMA electrode deposited in (2.3) is etched to form the desired pattern;

[0027] (2.5) Another insulating layer is deposited on the outer surface above the VCMA electrode obtained in step (2.4) and on the outer surface of the insulating film exposed above the VCMA electrode.

[0028] The method for manufacturing the antiferromagnetic memory device includes the following: the antiferromagnetic thin film structure can be replaced with a ferrimagnetic thin film structure; the ferrimagnetic thin film structure can be any one of a single-layer thin film composed of a single material or a multilayer stacked film composed of multiple materials.

[0029] By adopting the above technical solution, the present invention has the following beneficial effects:

[0030] The present invention relates to an antiferromagnetic memory device and its fabrication method, which enables information writing and reading methods with reduced device size. It not only fully possesses the ultra-high information writing speed at the terahertz level and the resistance to external magnetic interference of antiferromagnets, but also reduces the size of the device to about 10 nanometers, thereby achieving high-density storage.

[0031] Since the upper and lower interfaces of the antiferromagnetic thin film structure have unpaired spin electrons and exhibit weak magnetism in nanoscale thin films, it can be considered as a ferromagnet with very small ferromagnetization and very high coercivity. In addition, the subferromagnetic thin film structure has similar properties to the antiferromagnetic thin film structure, while exhibiting weaker ferromagnetism. Therefore, the storage and reading / writing based on the antiferromagnetic thin film structure of this invention can also be applied to subferromagnets.

[0032] In this invention, the spin electron direction of the antiferromagnetic thin film structure is used for information storage. Information retrieval is achieved through the synergistic effect of the different resistances of the antiferromagnetic thin film structure perpendicular to its surface at different spin electron directions (i.e., magnetoresistance effect), and the different resistances of the antiferromagnetic thin film structure, the tunnel insulating thin film structure, and the device composed of the ferromagnetic thin film structure at different spin electron directions. Information writing is achieved by the spin transfer torque (STT) exerted on the spin electrons of the antiferromagnetic thin film structure by two ferromagnetic bodies with opposite spin electron directions above and below the antiferromagnetic thin film structure through the tunnel insulating thin film structure. Unlike the writing principle of magnetic tunnel junction (MTJ) information writing using STT, this invention allows information writing to the antiferromagnetic thin film structure by applying current to the ferromagnetic thin film structure at one end, based on the spin electron direction of that end of the ferromagnetic thin film structure. Because the spin electrons of the ferromagnetic thin film structures at both ends of the antiferromagnetic thin film structure are in opposite directions, applying a write current from both ends will change the spin electron direction of the antiferromagnetic thin film structure. This invention has a structure similar to STT-MTJ, therefore its device size is expected to reach below 10 nanometers.

[0033] This invention not only possesses the ultra-high information writing speed at the terahertz level and the characteristics of resistance to external magnetic interference of antiferromagnetic thin film structures, but also solves the problem that current spintronic devices based on antiferromagnetic thin film structures used for MRAM are too large to be applied on a large scale in integrated circuits due to the use of traditional reading and writing methods (such as writing using spin orbital moment SOT and reading using anomalous Hall effect AHE). Attached Figure Description

[0034] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of the structure of the antiferromagnetic memory device according to Embodiment 1 of the present invention;

[0036] Figure 2 This is a schematic diagram of the structure of the antiferromagnetic magnetic storage device according to Embodiment 2 of the present invention;

[0037] Figure 3-7 This is a flowchart illustrating the fabrication process of the antiferromagnetic memory device of the present invention.

[0038] in, Figure 3 In the middle, Figure (A) is a schematic diagram of the fabrication of the first electrode and the first ferromagnetic thin film structure; Figure 3 (B) is for Figure 3 (A) A schematic diagram of applying a magnetic field to the first ferromagnetic thin film structure to fix the direction of the spin electrons of the first ferromagnetic thin film structure; Figure 3 (C) is a schematic diagram of the fabrication of the first tunnel insulating film structure; Figure 3 (D) is a schematic diagram of the fabrication of an antiferromagnetic thin film structure or a subferromagnetic thin film structure; Figure 3 (E) is a schematic diagram of the fabrication of the second tunnel insulating film structure; Figure 3 (F) is a schematic diagram of the fabrication of the first ferromagnetic thin film structure;

[0039] Figure 4 In the middle, Figure (A) shows the... Figure 3 (F) The structure prepared is applied and Figure 3 (B) Schematic diagram of opposite external magnetic fields; Figure 4 (B) The spin electron direction of the second ferromagnetic thin film structure is fixed and is consistent with... Figure 3 (B) Schematic diagram of the first ferromagnetic thin film structure with opposite spin electron directions; Figure 4 (C) is a schematic diagram of an antiferromagnetic device obtained by semiconductor etching-related techniques;

[0040] Figure 5 middle, Figure 5 (A) is a schematic diagram of the deposition of the insulating layer film; Figure 5 (B) is a schematic diagram of the deposition of the first insulating layer; Figure 5 (C) is a schematic diagram of the deposition of the sacrificial layer; Figure 5 (D) is a schematic diagram of etching back to bring the thickness of the sacrificial layer to the required thickness; Figure 5 (E) is a schematic diagram of shaping the sacrificial layer to the desired shape using semiconductor etching-related techniques;

[0041] Figure 6 middle, Figure 6 (A) is a schematic diagram of filling the second insulating layer and grinding it flat; Figure 6 (B) is a schematic diagram showing the grinding of the second insulating isolation layer down to the top of the second ferromagnetic thin film structure; Figure 6 (C) is a schematic diagram of the deposition of the second electrode; Figure 6 (D) is a schematic diagram of the second electrode being etched to the desired shape; Figure 6 (E) is a schematic diagram of filling and smoothing with a third insulating layer; Figure 6 (F) is a diagram of the drilling process;

[0042] Figure 7 middle, Figure 7 (A) is a schematic diagram showing the etching of the sacrificial layer; Figure 7 (B) is a schematic diagram of the deposited VCMA electrode; Figure 7 (C) is Figure 6 (F) The VCMA electrode at the hole location is etched away, and a schematic diagram of the deposited wire is shown.

[0043] Figure 8 This is another embodiment of the VCMA electrode fabrication process in the fabrication method of the antiferromagnetic memory device of the present invention; wherein, Figure 8 (A) is a schematic diagram of depositing a fourth insulating isolation layer at the bottom of the antiferromagnetic device where no VCMA electrode is required after depositing an insulating film on the outer surface of the antiferromagnetic device. Figure 8 (B) is a schematic diagram of depositing VCMA electrodes to a thickness exceeding that of the antiferromagnetic device; Figure 8 (C) is a schematic diagram of etching back to ensure that the thickness of the VCMA electrode is not greater than the thickness of the antiferromagnetic thin film structure; Figure 8 (D) is a schematic diagram of the deposition of the fifth insulating isolation layer;

[0044] Figure 9 This is another embodiment of the VCMA electrode fabrication process in the fabrication method of the antiferromagnetic memory device of the present invention; wherein, Figure 9 (A) is a schematic diagram of depositing a sixth insulating isolation layer at the bottom of the antiferromagnetic device where no VCMA electrode is required after depositing an insulating film on the outer surface of the antiferromagnetic device. Figure 9 (B) is in Figure 9 (A) Schematic diagram of VCMA electrode deposition on the outer surface of the formed structure; Figure 9 (C) is the VCMA electrode that has been etched away beyond the thickness of the antiferromagnetic thin film structure; Figure 9 (D) is a schematic diagram of the deposition of the seventh insulating isolation layer. Detailed Implementation

[0045] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] In the description of this invention, it should be noted that the terms "upper," "lower," "top," "bottom," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," "third," "fourth," "fifth," "sixth," and "seventh" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] The present invention will be further explained below with reference to specific embodiments.

[0048] Example 1

[0049] like Figure 1 As shown, the antiferromagnetic memory device provided in Embodiment 1 of the present invention includes a first ferromagnetic thin film structure 1, a first tunnel insulating thin film structure 2 disposed on the upper part of the first ferromagnetic thin film structure 1, an antiferromagnetic thin film structure 3 disposed on the upper part of the first tunnel insulating thin film structure 2, a second tunnel insulating thin film structure 4 disposed on the upper part of the antiferromagnetic thin film structure 3, and a second ferromagnetic thin film structure 5 disposed on the upper part of the second tunnel insulating thin film structure 4.

[0050] Both the first ferromagnetic thin film structure 1 and the second ferromagnetic thin film structure 5 can be composed of a single ferromagnetic thin film layer, or multiple ferromagnetic thin film layers, or a single ferromagnetic thin film layer and a single non-ferromagnetic thin film layer, or multiple ferromagnetic thin film layers and non-ferromagnetic thin film layers; wherein, the ferromagnetic thin film layer is typically a CoFeB alloy, etc. The spin electrons of the first ferromagnetic thin film structure 1 and the second ferromagnetic thin film structure 5 are fixed in opposite directions.

[0051] The first tunnel insulating film structure 2 and the second tunnel insulating film structure 4 are both non-magnetic film structures, which can be either multilayer heterogeneous structures composed of different materials or single structures composed of the same material; the non-magnetic film structure is a material other than magnetic; the tunnel insulating film is usually MgO, etc.

[0052] The first ferromagnetic thin film structure 1 has a first electrode 9 at its bottom and the second ferromagnetic thin film structure 5 has a second electrode 10 at its top.

[0053] The antiferromagnetic thin film structure 3 can be composed of a single antiferromagnetic thin film layer, or multiple antiferromagnetic thin film layers, or a single antiferromagnetic thin film layer and a single non-magnetic thin film layer, or multiple antiferromagnetic thin film layers and a single non-magnetic thin film layer; wherein, the antiferromagnetic thin film structure 3 is typically a Mn3X series alloy (such as Mn3Sn, etc.), a CuMnAs series compound, or an antiferromagnetic oxide (such as Cr2O3, NiO, etc.).

[0054] The antiferromagnetic thin film structure 3 can also be a ferrimagnetic thin film structure, which can be composed of a single ferrimagnetic thin film layer, or multiple ferrimagnetic thin film layers, or a single ferrimagnetic thin film layer and a single non-magnetic thin film layer, or multiple ferrimagnetic thin film layers and a single non-magnetic thin film layer.

[0055] Example 2

[0056] like Figure 2 As shown, the difference between Embodiment 2 and Embodiment 1 is that: an insulating film 6 is provided around the sides of the antiferromagnetic thin film structure 3, and a VCMA electrode 7, which can apply voltage to control the magnetic anisotropy of the antiferromagnetic thin film structure 3, surrounds the outer surface of the insulating film 6. One end of the VCMA electrode 7 surrounds the outer surface of the insulating film 6, and the other end extends outward from the insulating film 6, with a wire 8 connected to the outside.

[0057] The VCMA electrode 7 can be any of a multilayer heterogeneous structure composed of different materials or a single structure composed of the same material. The VCMA electrode 7 can be connected to the outer surface of the insulating film 6 using any of the following methods: completely surrounding the outer surface of the insulating film 6, partially surrounding the outer surface of the insulating film 6, or partially contacting the outer surface of the insulating film 6. Adding a VCMA electrode 7 to the side of the antiferromagnetic thin film structure 3, which allows for voltage application to control magnetic anisotropy, assists the first ferromagnetic thin film structure 1 or the second ferromagnetic thin film structure 5 in performing STT writing on the antiferromagnetic thin film structure 3, thereby reducing the energy consumption for writing the required information.

[0058] The materials of the first ferromagnetic thin film structure 1, the first tunnel insulating thin film structure 2, the antiferromagnetic thin film structure 3, the second tunnel insulating thin film structure 4, the second ferromagnetic thin film structure 5, the insulating layer film 6, and the VCMA electrode 7 can all have their relevant properties improved through material doping.

[0059] The main steps of the fabrication method of the antiferromagnetic memory device of the present invention are as follows:

[0060] A first electrode 9 is fabricated on a substrate 01. Then, a first ferromagnetic thin film structure 1 is fabricated on the fabricated first electrode 9. Next, an external magnetic field is applied to align the spin electrons of the first ferromagnetic thin film structure 1 in any direction. Then, a first tunnel insulating thin film structure 2 is fabricated on the fabricated first ferromagnetic thin film structure 1. Next, either an antiferromagnetic thin film structure 3 or a subferromagnetic thin film structure is fabricated on the first tunnel insulating thin film structure 2. Next, a second tunnel insulating thin film structure 4 is fabricated on either the antiferromagnetic thin film structure 3 or the subferromagnetic thin film structure. Next, a second ferromagnetic thin film structure 5 is fabricated on the second tunnel insulating thin film structure 4. Then, an external magnetic field is applied to align the spin electrons of the second ferromagnetic thin film structure 5 in the opposite direction to the spin electrons of the first ferromagnetic thin film structure 1. Finally, a second electrode 10 is fabricated on the second ferromagnetic thin film structure 5.

[0061] The method for fabricating the antiferromagnetic memory device of the present invention specifically includes the following main steps:

[0062] (1.1) As Figure 3 As shown in (A), the first electrode 9 is first fabricated on the substrate 01, as follows: Figure 3 (B) shows the fabrication of a first ferromagnetic thin film structure 1 on the first electrode 9 and the application of a downward magnetic field to the first ferromagnetic thin film structure 1. Figure 3 (C) shows that a first tunnel insulating film structure 2 is then fabricated on the upper part of the first ferromagnetic thin film structure 1, as shown in Figure 2. Figure 3 As shown in (D), an antiferromagnetic thin film structure 3 (or a subferromagnetic thin film structure) is fabricated on the first tunnel insulating thin film structure 2, such as... Figure 3 As shown in (E), a second tunnel insulating film structure 4 is then fabricated on top of the antiferromagnetic thin film structure 3, as follows: Figure 3 As shown in (F), a second ferromagnetic thin film structure 5 is fabricated on the upper part of the second tunnel insulating thin film structure 4, as follows: Figure 4 (A) and Figure 4 (B) shows the application of an upward magnetic field to the second ferromagnetic thin film structure 5, as shown in Figure 5. Figure 4 (C) shows that the first ferromagnetic thin film structure 1, the first tunnel insulating thin film structure 2, the antiferromagnetic thin film structure 3, the second tunnel insulating thin film structure 4, and the second ferromagnetic thin film structure 5 are then formed into an antiferromagnetic device using semiconductor etching technology (the ideal shape of this antiferromagnetic device is cylindrical, but in practice it is usually frustum-shaped). Figure 5 (A) shows the preparation of an insulating thin film 6 on the outer surface of the antiferromagnetic device; wherein, the direction of the magnetic field applied to the first ferromagnetic thin film structure 1 and the second ferromagnetic thin film structure 5 is only required to ensure that the spin directions of the first ferromagnetic thin film structure 1 and the second ferromagnetic thin film structure 5 are opposite.

[0063] (1.2) such as Figure 5 (B) shows that a first insulating layer 11 is deposited in the part of the antiferromagnetic device where no voltage is required;

[0064] (1.3) such as Figure 5 (C) shows that a sacrificial layer 12 with a different etch selectivity than the first insulating isolation layer 11 in step (1.2) is deposited at the location where voltage needs to be applied to the antiferromagnetic device; wherein, as Figure 5 (D) The sacrificial layer 12 shown can be directly deposited to the required thickness, or it can be deposited to a thickness exceeding that of the antiferromagnetic thin film structure 3 and then etched back to the required thickness, so that the thickness of the etched sacrificial layer is less than or equal to the thickness of the antiferromagnetic thin film structure 3.

[0065] (1.4) such as Figure 5 (E) shows the etching process performed on the sacrificial layer 12 obtained in step (1.3) to form the desired pattern; wherein, as shown in Figure (E), Figure 5 As shown in (E), the sacrificial layer 12 obtained in step (1.3) can also be left unetched.

[0066] (1.5) such as Figure 6 (A) shows the deposition of a second insulating isolation layer 13 on the top and sides of the sacrificial layer 12 obtained in step (1.4); as shown Figure 6 (B) The upper part of the second insulating layer 13 is then ground flat until the top of the second ferromagnetic thin film structure 5 is exposed;

[0067] (1.6) such as Figure 6 As shown in (C), a second electrode 10 is then deposited on the second ferromagnetic thin film structure 5 to which a voltage needs to be applied, as shown in Figure 5. Figure 6 (D) shows that after etching the second electrode 10, it is made to have a non-overlapping portion with the sacrificial layer 12 in step (1.4) from a top-view perspective, as shown. Figure 6 (E) is then covered with a third insulating layer 14 and ground smooth;

[0068] (1.7) such as Figure 6 (F) shows that a hole 15 is etched above the third insulating isolation layer 14, which does not overlap with the second electrode 10 in step (1.6), to the contact sacrificial layer 12, as shown. Figure 7 As shown in (A), the sacrificial layer 12 is etched away;

[0069] (1.8) such as Figure 7 (B) As shown in step (1.7), a VCMA electrode 7 is deposited at the location where the sacrificial layer 12 is etched away;

[0070] (1.9) such as Figure 7As shown in (C), the excess VCMA electrode 7 located at the hole 15 in step (1.7) is then etched away and the wire 8 connecting the VCMA electrode 7 to the outside is deposited, thus forming a VCMA electrode 7 that can apply voltage to the antiferromagnetic thin film structure.

[0071] like Figure 8 As shown, the fabrication method of the antiferromagnetic memory device of the present invention can also be implemented according to the following steps:

[0072] (2.1) In such Figure 5 (A) shows an antiferromagnetic device with a thin insulating layer 6 deposited on its surface;

[0073] (2.2) As Figure 8 (A) shows the deposition of a fourth insulating layer 21 in the portion of the antiferromagnetic device where no voltage is required;

[0074] (2.3) such as Figure 8 (B) As shown, a VCMA electrode is then deposited on the outer surface of the insulating film 6 corresponding to the side surface of the antiferromagnetic thin film structure 3 of the antiferromagnetic device; wherein, as Figure 8 The VCMA electrode 7 shown in (C) can be directly deposited to the required thickness, such as Figure 8 (B) can also be deposited beyond the thickness of the antiferromagnetic device and then etched back to the required thickness so that the thickness of the deposited VCMA electrode is less than or equal to the thickness of the antiferromagnetic thin film structure.

[0075] (2.4) such as Figure 8 (C) shows the etching process performed on the VCMA electrode 7 deposited in step (2.3) to form the desired pattern;

[0076] (2.5) such as Figure 8 As shown in (D), a fifth insulating layer 22 is deposited on the outer surface of the insulating film 6 above the VCMA electrode 7 obtained in step (2.4).

[0077] The antiferromagnetic thin film structure can be replaced with a ferrimagnetic thin film structure, and the outer surface of the ferrimagnetic thin film structure is provided with a VCMA electrode that can be applied to control the magnetic anisotropy. The ferrimagnetic thin film structure can be a single-layer thin film composed of a single material, or a multilayer stacked film composed of multiple materials.

[0078] The method for fabricating the antiferromagnetic memory device of the present invention can also be implemented according to the following steps:

[0079] (3.1) In such Figure 5 (A) shows an antiferromagnetic device with a thin insulating layer 6 deposited on its surface;

[0080] (3.2) such as Figure 9(A) shows the deposition of a sixth insulating layer 31 in the portion of the antiferromagnetic device where no voltage is required;

[0081] (3.3) such as Figure 9 (B) As shown, a VCMA electrode 7 is deposited on the outer surface of the insulating film 6 corresponding to the side of the antiferromagnetic thin film structure 3 of the antiferromagnetic device; wherein, as Figure 9 (C) The VCMA electrode 7 shown can be directly deposited to the required thickness, or it can be deposited beyond the thickness of the antiferromagnetic device and then etched back to the required thickness, so that the thickness of the thickest part of the deposited VCMA electrode is less than or equal to the thickness of the antiferromagnetic thin film structure.

[0082] (3.4) such as Figure 9 (C) shows the etching process performed on the VCMA electrode 7 deposited in step (3.3) to form the desired pattern;

[0083] (3.5) such as Figure 9 As shown in (D), a seventh insulating layer 32 is deposited on the outer surface above the VCMA electrode 7 obtained in step (3.4) and on the outer surface of the insulating film 6 exposed above the VCMA electrode 7.

[0084] This invention enables information writing and reading methods that reduce device size. It not only fully possesses the ultra-high information writing speed at the terahertz level and the resistance to external magnetic interference of antiferromagnets, but also reduces the size of the device to about 10 nanometers, thus achieving high-density storage.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An antiferromagnetic memory device, characterized in that: The memory device includes a ferromagnetic thin film structure, an antiferromagnetic thin film structure, and a tunnel insulating thin film structure sandwiched between the ferromagnetic thin film structure and the antiferromagnetic thin film structure. The memory device includes a first ferromagnetic thin film structure, a first tunnel insulating thin film structure disposed on the upper part of the first ferromagnetic thin film structure, an antiferromagnetic thin film structure disposed on the upper part of the first tunnel insulating thin film structure, a second tunnel insulating thin film structure disposed on the upper part of the antiferromagnetic thin film structure, and a second ferromagnetic thin film structure disposed on the upper part of the second tunnel insulating thin film structure; the spin electrons of the first ferromagnetic thin film structure and the second ferromagnetic thin film structure are fixed in opposite directions; the first ferromagnetic thin film structure, the first tunnel insulating thin film structure, the antiferromagnetic thin film structure, the second tunnel insulating thin film structure, and the second ferromagnetic thin film structure are all constructed using any one of the following structures: a single-layer thin film composed of a single material and a multilayer stacked film composed of multiple materials. The antiferromagnetic thin film structure is provided with VCMA electrodes around its sides, which are applied with voltage to control magnetic anisotropy; the VCMA electrodes are either multilayer heterostructures composed of different materials or single structures composed of the same material. The antiferromagnetic thin film structure has an insulating film around its sides; the VCMA electrode is connected to the outer surface of the insulating film by either completely surrounding it or partially contacting it.

2. The antiferromagnetic memory device as claimed in claim 1, characterized in that: The ferromagnetic thin film structure, antiferromagnetic thin film structure, and tunnel insulating thin film structure all adopt any one of the following structures: a single-layer thin film composed of a single material and a multi-layer stacked film composed of multiple materials.

3. The antiferromagnetic memory device as described in claim 1, characterized in that: The antiferromagnetic thin film structure is replaced with a ferrimagnetic thin film structure; the ferrimagnetic thin film structure can be any one of a single-layer thin film composed of a single material or a multilayer stacked film composed of multiple materials.

4. A method for manufacturing an antiferromagnetic memory device as described in any one of claims 1 to 3, characterized in that, It includes the following main steps: A first electrode is fabricated on a substrate, and then a first ferromagnetic thin film structure is fabricated on the fabricated first electrode. Next, an external magnetic field is applied to align the spin electrons of the first ferromagnetic thin film structure in any direction. Then, a first tunnel insulating thin film structure is fabricated on the fabricated first ferromagnetic thin film structure. Next, an antiferromagnetic thin film structure is fabricated on the first tunnel insulating thin film structure. Then, a second tunnel insulating thin film structure is fabricated on the antiferromagnetic thin film structure. Next, a second ferromagnetic thin film structure is fabricated on the second tunnel insulating thin film structure. Then, an external magnetic field is applied to align the spin electrons of the second ferromagnetic thin film structure in the opposite direction to the spin electrons of the first ferromagnetic thin film structure. Finally, a second electrode is fabricated on the second ferromagnetic thin film structure.

5. The method for manufacturing the antiferromagnetic memory device as described in claim 4, characterized in that, It includes the following main steps: (1.1) First, a first electrode and a multilayer thin film structure consisting of a ferromagnetic thin film structure, a tunnel insulating thin film structure and an antiferromagnetic thin film structure are prepared. Then, an antiferromagnetic device is formed by semiconductor etching technology. Finally, an insulating thin film is prepared on the outer surface of the antiferromagnetic device. (1.2) Then, an insulating isolation layer is deposited on the part of the antiferromagnetic thin film structure of the antiferromagnetic device where no voltage is required; (1.3) Then deposit a sacrificial layer with a different etch selectivity than the insulating isolation layer in step (1.2) at the location where voltage needs to be applied to the antiferromagnetic device and selectively etch it away; the sacrificial layer is deposited directly to the required thickness or deposited first to a thickness exceeding the thickness of the antiferromagnetic thin film structure and then etched back to the required thickness, either of these two deposition methods, such that the thickness of the etched sacrificial layer is ≤ the thickness of the antiferromagnetic thin film structure; (1.4) Then deposit an insulating layer on top of and to the side of the sacrificial layer obtained in step (1.3); (1.5) Then deposit a second electrode material at one end of the ferromagnetic thin film structure to which voltage needs to be applied, and etch the second electrode so that the prepared second electrode and the sacrificial layer in step (1.3) have a non-overlapping part in the top view. Then cover it with an insulating isolation layer and grind it flat. (1.6) Then, etch and drill holes above the sacrificial layer that does not overlap with the second electrode in step (1.5) until contact with the sacrificial layer, and etch away the sacrificial layer; (1.7) Deposit a VCMA electrode at the location where the sacrificial layer was etched away in step (1.6); (1.8) Then etch away the excess VCMA electrode material at the location of the hole in step (1.6) and deposit the external wires connected to the VCMA electrode material to finally form the VCMA electrode that applies voltage to the antiferromagnetic thin film structure.

6. The method for manufacturing the antiferromagnetic memory device as described in claim 5, characterized in that, The VCMA electrode is also prepared according to the following main steps: (2.1) Deposit an insulating thin film on the surface of the antiferromagnetic device; (2.2) Deposit an insulating layer in the portion of the antiferromagnetic device where no voltage needs to be applied; (2.3) Then deposit a VCMA electrode on the outer side of the insulating film corresponding to the side of the antiferromagnetic thin film structure of the antiferromagnetic device; the VCMA electrode is deposited by either direct deposition to the required thickness or deposition exceeding the thickness of the antiferromagnetic thin film structure and then etching back to the required thickness, such that the thickness of the VCMA electrode after deposition is ≤ the thickness of the antiferromagnetic thin film structure. (2.4) The VCMA electrode deposited in (2.3) is etched to form the desired pattern; (2.5) Deposit another insulating layer on the outer surface above the VCMA electrode obtained in step (2.4) and on the outer surface of the insulating film exposed above the VCMA electrode.

7. The method for manufacturing the antiferromagnetic memory device according to any one of claims 4 to 6, characterized in that: The antiferromagnetic thin film structure is replaced with a ferrimagnetic thin film structure; the ferrimagnetic thin film structure can be any one of a single-layer thin film composed of a single material or a multilayer stacked film composed of multiple materials.

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