Magnetic memory and method for manufacturing the same

Abstract

The present application provides a magnetic memory and a preparation method thereof, which relates to the field of semiconductor technology and is used to solve the technical problem of poor magnetic resistance of the magnetic memory. The magnetic memory includes a substrate, a magnetic tunnel junction arranged on the substrate, a top electrode arranged on the magnetic tunnel junction, and a passivation layer arranged on the top electrode; the top electrode is electrically connected to the magnetic tunnel junction, and the top electrode is constructed to present a preset pattern. The stress of the passivation layer is set according to the shape of the top electrode and the magnetostriction coefficient of the magnetic tunnel junction to increase the coercive field of the magnetic tunnel junction. The present application can enhance the effect of inducing magnetic anisotropy of the magnetic tunnel junction, enhance the coercive field performance of the magnetic tunnel junction, thereby improving the magnetic resistance of the magnetic memory and improving the stability of data storage.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a magnetic memory and a method for preparing the same. Background Art

[0002] Magnetic Tunnel Junction (MTJ) is the core structural unit of magnetic storage. The size of its characteristic size determines the storage capacity and working efficiency of the magnetic storage. The magnetic tunnel junction needs to achieve the purpose of stable data storage through magnetic anisotropy.

[0003] In the related art, a high-stress conductive hard mask layer is arranged above the magnetic tunnel junction to generate magnetic anisotropy; or, the magnetic anisotropy is generated by making the major axis and minor axis of the magnetic tunnel junction have a certain aspect ratio; or, a high-stress electrode layer is arranged below the magnetic tunnel junction to generate magnetic anisotropy.

[0004] However, in the related art, there is a technical problem that the coercive field performance of the magnetic tunnel junction is low, resulting in poor anti-magnetic ability of the magnetic memory and poor data storage stability. Summary of the invention

[0005] In view of the above problems, the embodiments of the present application provide a magnetic memory and a method for preparing the same, which can improve the effect of inducing magnetic anisotropy of a magnetic tunnel junction and enhance the coercive field performance of the magnetic tunnel junction, thereby improving the magnetic resistance of the magnetic memory and improving the stability of data storage.

[0006] In order to achieve the above objectives, the embodiments of the present application provide the following technical solutions:

[0007] The present application provides a magnetic storage device, comprising:

[0008] A substrate, a magnetic tunnel junction disposed on the substrate, a top electrode disposed on the magnetic tunnel junction, and a passivation layer disposed on the top electrode;

[0009] The top electrode is electrically connected to the magnetic tunnel junction and is constructed to present a preset pattern. The stress of the passivation layer is set according to the shape of the top electrode and the magnetostriction coefficient of the magnetic tunnel junction to increase the coercive field of the magnetic tunnel junction.

[0010] In some optional embodiments, the magnetostriction coefficient of the magnetic tunnel junction is greater than zero; the length of the top electrode in the first direction is less than the length in the second direction, the stress of the passivation layer is set to compressive stress, the first direction is the short axis direction of the magnetic tunnel junction; the second direction is the long axis direction of the magnetic tunnel junction.

[0011] In some optional embodiments, the magnetostriction coefficient of the magnetic tunnel junction is greater than zero; the length of the top electrode in the first direction is greater than the length in the second direction, the stress of the passivation layer is set to tensile stress, the first direction is the short axis direction of the magnetic tunnel junction; the second direction is the long axis direction of the magnetic tunnel junction.

[0012] In some optional embodiments, the magnetostriction coefficient of the magnetic tunnel junction is less than zero; the length of the top electrode in the first direction is less than the length in the second direction, the stress of the passivation layer is set to tensile stress, the first direction is the short axis direction of the magnetic tunnel junction; the second direction is the long axis direction of the magnetic tunnel junction.

[0013] In some optional embodiments, the magnetostriction coefficient of the magnetic tunnel junction is less than zero; the length of the top electrode in the first direction is greater than the length in the second direction, the stress of the passivation layer is set to compressive stress, the first direction is the short axis direction of the magnetic tunnel junction; the second direction is the long axis direction of the magnetic tunnel junction.

[0014] In some optional embodiments, the contour shape of the magnetic tunnel junction includes at least one of an ellipse, a circle, a rectangle, and a square.

[0015] In some optional embodiments, the passivation layer includes at least one of a silicon nitride layer and a silicon oxide layer.

[0016] A second aspect of an embodiment of the present application provides a method for preparing a magnetic memory, the method comprising:

[0017] providing a substrate;

[0018] forming a magnetic tunnel junction on the substrate;

[0019] forming a top electrode on the magnetic tunnel junction, and performing patterning on the top electrode so that the top electrode is in a preset pattern, and the top electrode is electrically connected to the magnetic tunnel junction;

[0020] A passivation layer is formed on the top electrode; wherein the stress of the passivation layer is determined according to the shape of the top electrode and the magnetostriction coefficient of the magnetic tunnel junction, so as to increase the coercive field of the magnetic tunnel junction.

[0021] In some optional embodiments, before forming a top electrode on the magnetic tunnel junction, the method includes:

[0022] forming a dielectric protection layer on the magnetic tunnel junction;

[0023] forming an interlayer dielectric layer on the dielectric protection layer;

[0024] performing a planarization process on the surface of the interlayer dielectric layer;

[0025] Electrode holes are formed on the interlayer dielectric layer after the planarization process.

[0026] In some optional embodiments, forming a passivation layer on the top electrode specifically includes:

[0027] At least one of a silicon oxide material and a silicon nitride material is deposited on the top electrode to form a passivation layer according to the shape of the top electrode and the magnetostriction coefficient of the magnetic tunnel junction.

[0028] In the magnetic memory and the preparation method thereof provided in the embodiments of the present application, a top electrode with a preset pattern is arranged on the magnetic tunnel junction, and a passivation layer is arranged on the top electrode in combination with the shape of the top electrode, so that the stress of the passivation layer is determined according to the shape of the top electrode and the magnetostriction coefficient of the magnetic tunnel junction, so as to enhance the effect of inducing the magnetic tunnel junction to generate magnetic anisotropy, thereby enhancing the coercive field performance of the magnetic tunnel junction, and further enhancing the anti-magnetic ability of the magnetic memory and the stability of data storage.

[0029] In addition to the technical problems solved by the embodiments of the present application, the technical features that constitute the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions described above, other technical problems that can be solved by the magnetic storage device and the preparation method thereof provided by the embodiments of the present application, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further described in detail in the specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 A top view of a structure of a magnetic memory provided in an embodiment of the present application and a cross-sectional schematic diagram at AA in the top view;

[0032] Figure 2 for Figure 1 Schematic diagram of the stress state of the passivation layer;

[0033] Figure 3 A top view of another structure of a magnetic memory provided in an embodiment of the present application and a cross-sectional schematic diagram at BB in the top view;

[0034] Figure 4 for Figure 3 Schematic diagram of the stress state of the passivation layer;

[0035] Figure 5 A top view of another structure of a magnetic memory provided in an embodiment of the present application and a cross-sectional schematic diagram at CC in the top view;

[0036] Figure 6 for Figure 5 Schematic diagram of the stress state of the passivation layer;

[0037] Figure 7 A top view of another structure of a magnetic memory provided in an embodiment of the present application and a cross-sectional schematic diagram at DD in the top view;

[0038] Figure 8 for Figure 5 Schematic diagram of the stress state of the passivation layer;

[0039] Fig. 9 A schematic diagram of a method for preparing a magnetic memory provided in an embodiment of the present application;

[0040] Figures 10 to 16 Schematic diagram of the top view and cross-sectional structure of each structure in the preparation process of the magnetic memory provided in the embodiment of the present application.

[0041] Reference numerals:

[0042] 10- Magnetic storage;

[0043] 100-substrate; 200-bottom electrode;

[0044] 300-magnetic tunnel junction; 300a-initial magnetic tunnel junction;

[0045] 400-hard mask layer; 410-hard mask structure;

[0046] 500-photoresist; 600-dielectric protection layer;

[0047] 700-interlayer dielectric layer; 710-electrode hole;

[0048] 800-top electrode; 900-passivation layer. DETAILED DESCRIPTION

[0049] Coercive force, also known as coercive field or coercive force, is one of the characteristics of magnetic materials. It refers to the magnetic field strength required to reduce the magnetization intensity of the magnetic material to zero after it has been magnetized to magnetic saturation. Coercive force represents the ability of magnetic materials to resist demagnetization. It can be expressed by Hc, with units of A / m (International Standard System) or Oe (Gaussian System). Coercive force can be measured by a magnetometer or a BH analyzer.

[0050] The coercive field (Hc) performance of the magnetic tunnel junction needs to reach a certain level to meet the anti-magnetic ability of the magnetic memory; the coercive field performance of the magnetic tunnel junction is related to the oriented magnetic anisotropy; in the related technology, a high-stress conductive hard mask layer is set above the magnetic tunnel junction to produce magnetic anisotropy; or, by making the major axis and minor axis of the magnetic tunnel junction have a certain aspect ratio, magnetic anisotropy is produced; or, a high-stress electrode layer is set below the magnetic tunnel junction to produce magnetic anisotropy.

[0051] However, in the related art, while inducing magnetic anisotropy, there is a technical problem that the coercive field performance of the magnetic tunnel junction is low, resulting in poor anti-magnetic ability of the magnetic memory and poor data storage stability.

[0052] In order to solve the above problems, the present application provides a magnetic memory and a preparation method thereof. The magnetic memory is provided with a top electrode in a preset pattern on a magnetic tunnel junction, and a passivation layer is provided on the top electrode in combination with the shape of the top electrode, so that the stress of the passivation layer is determined according to the shape of the top electrode and the magnetostriction coefficient of the magnetic tunnel junction, so as to enhance the effect of inducing the magnetic tunnel junction to generate magnetic anisotropy, thereby enhancing the coercive field performance of the magnetic tunnel junction, and further enhancing the anti-magnetic ability of the magnetic memory and the stability of data storage.

[0053] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present application more obvious and understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of this application.

[0054] The embodiment of the present application provides a magnetic memory, which may include a plurality of memory cells, which may be arranged along rows and columns, or in other words, the plurality of memory cells may be arranged in a matrix form. Among them, the memory cells in the same row (or the same column) may be coupled to the same word line (word line, referred to as WL), and the memory cells in the same column (or the same row) may be coupled to the same group of bit lines (bit line, referred to as BL) and source lines. In other words, the memory cell may be a three-terminal device, and the memory cell may include a first end coupled to the word line, a second end coupled to the bit line, and a third end coupled to the source line.

[0055] In the embodiments of this application, please combine Figure 1As shown, the memory cell includes a substrate 100, which can serve as a basic support structure of the memory cell, and can provide support for the structural layers stacked thereon. Exemplarily, the substrate 100 can be a silicon substrate, a germanium substrate, a silicon carbide substrate, a silicon germanium substrate, a Germanium on Insulator (GOI) substrate, or a Silicon on Insulator (SOI) substrate, etc.

[0056] In some embodiments, the memory cell further includes a bottom electrode 200, a magnetic tunnel junction 300, and a top electrode 800. Exemplarily, the bottom electrode 200 is disposed between the substrate 100 and the magnetic tunnel junction 300, that is, the bottom electrode 200 and the magnetic tunnel junction 300 are stacked from bottom to top on the substrate 100 along the thickness direction of the substrate 100, the top electrode 800 is disposed above the magnetic tunnel junction 300, and the bottom electrode 200 and the top electrode 800 are electrically connected to the magnetic tunnel junction 300, respectively.

[0057] In some embodiments, the magnetic tunnel junction 300 may include a free layer, a tunneling barrier layer, a reference layer and a pinned layer stacked in sequence, wherein the free layer is disposed close to the bottom electrode 200, and the bottom electrode 200 is a spin-orbit torque layer that can generate a spin current when current flows through it to generate a torque and change the resistance state of the magnetic tunnel junction 300, and the tunneling barrier layer is located between the reference layer and the free layer; the pinned layer is disposed on the side of the reference layer away from the tunneling barrier layer.

[0058] It should be noted that the pinning layer is used to pin the magnetization direction of the reference layer in a fixed direction. For example, the pinning layer pins the magnetization direction of the reference layer in the direction of its long axis.

[0059] The pinned layer may be a stacked layer, and the pinned layer may include ferromagnetic material layers and non-ferromagnetic material layers alternately stacked. For example, the pinned layer may include two ferromagnetic material layers and a non-ferromagnetic material layer disposed between the two ferromagnetic material layers.

[0060] In some embodiments, please combine Figure 1 As shown, the bottom electrode 200 is arranged below the magnetic tunnel junction 300, and the free layer, tunnel barrier layer, reference layer and pinned layer are stacked in sequence from bottom to top, that is, the free layer is arranged close to the bottom electrode 200, so that the magnetic tunnel junction 300 is formed into a top pinned structure.

[0061] The magnetic field direction of the reference layer is fixed, while the magnetic field polarization direction of the free layer can be changed. The tunnel barrier layer separates the reference layer and the free layer. Under the action of the electric field formed between the bottom electrode 200 and the top electrode 800, electrons will tunnel through the potential barrier of the tunnel barrier layer and vertically pass through the magnetic tunnel junction 300. The degree to which the current can tunnel and the resistance of the magnetic tunnel junction 300 are determined by the relative magnetization direction between the free layer and the reference layer.

[0062] When the magnetic field direction of the free layer is the same as that of the reference layer, the magnetic tunnel junction 300 presents a low resistance state (P state), and the resistance value of the magnetic memory 10 is the smallest. At this time, the data stored in the magnetic memory 10 is "0". When the magnetic field direction of the free layer is opposite to that of the reference layer, the magnetic tunnel junction 300 presents a high resistance state (AP state), and the resistance value of the magnetic memory 10 is the largest. At this time, the data stored in the magnetic memory 10 is "1".

[0063] The material forming the reference layer and the free layer may be a ferromagnetic material. For example, the material of the reference layer and the free layer may include at least one of cobalt (Co), iron (Fe), boron (B), nickel (Ni), ruthenium (Ru), iridium (Ir), and platinum (Pt). The material forming the tunnel layer may be an insulating material. For example, the material of the tunnel layer includes at least one of magnesium oxide (MgO), aluminum oxide (Al2O3), and silicon oxide (SiO2).

[0064] Since the magnetic tunnel junction 300 needs magnetic anisotropy to maintain the magnetic moment direction determined by the low resistance state and the high resistance state, in order to achieve the purpose of stable data storage, therefore, in order to enhance the effect of inducing the magnetic anisotropy of the magnetic tunnel junction 300, in the embodiment of the present application, the top electrode 800 is patterned so that the pattern of the top electrode 800 is a preset pattern, and a passivation layer 900 is formed on the top electrode 800, and the stress of the passivation layer 900 is determined according to the shape of the top electrode 800 and the magnetostriction coefficient of the magnetic tunnel junction 300.

[0065] In some embodiments, the contour shape of the magnetic tunnel junction 300 includes but is not limited to at least one of an ellipse, a circle, a rectangle, and a square. The contour shape can be adaptively designed according to actual needs and is not limited here.

[0066] For example, in Figure 1 and Figure 3 In the figure, the outline of the magnetic tunnel junction 300 is an ellipse. Figure 5 and Figure 7 In FIG. 3 , the outline shape of the magnetic tunnel junction 300 is circular.

[0067] The passivation layer 900 may be a passivation dielectric layer with high stress; illustratively, the passivation layer 900 may include one of a silicon nitride layer and a silicon oxide layer, or the passivation layer 900 may also be a composite layer of a silicon nitride layer and a silicon oxide layer.

[0068] In the embodiment of the present application, the top electrode 800 is patterned and etched so that the top electrode 800 is in a preset pattern, and a passivation layer 900 is arranged on the top electrode 800 in the preset pattern, and the stress property and size of the passivation layer 900 are set according to the magnetostriction coefficient in the magnetic tunnel junction 300 and the graphic shape of the top electrode 800. In this way, on the one hand, the passivation layer 900 and the top electrode 800 can be used to transfer anisotropic stress to induce the in-plane magnetic anisotropy of the magnetic tunnel junction 300, thereby enhancing the coercive field performance of the magnetic tunnel junction 300. Thereby improving the anti-magnetic ability of the magnetic memory 10 and enhancing the stability of data storage; alternatively, the size of the magnetic tunnel junction 300 can be reduced while ensuring that the coercive field performance of the magnetic tunnel junction 300 is not reduced, thereby improving the layout density of the magnetic memory 10; on the other hand, the coercive field Hc of the magnetic tunnel junction 300 and the write current of the bottom electrode 200 can be decoupled from each other, so that while maintaining a relatively high coercive field performance, power consumption can be further reduced; on another hand, there is no need to add additional process steps, the process is simple, and thus the process cost can be reduced.

[0069] It can be understood that the stress property and size of the passivation layer 900 are respectively adapted to the magnetostriction coefficient of the magnetic tunnel junction 300 and the shape of the top electrode 800 .

[0070] Among them, the magnetostriction coefficient refers to the phenomenon that when a ferromagnetic material is magnetized, its length will be extended or shortened along the magnetization direction. This phenomenon can be expressed by the magnetostriction coefficient λ. The magnitude of λ is equal to the ratio of the elongation along the magnetization direction to the total length, and the unit is generally ppm. λ>0 means that the size along the magnetization direction is extended, which is called positive magnetostriction, such as iron; conversely, λ<0 means that the size along the magnetization direction is shortened, which is called negative magnetostriction, such as nickel.

[0071] In some embodiments, the magnetostriction coefficient λ of the magnetic tunnel junction 300 is greater than 0, the length of the top electrode 800 in the first direction is less than the length in the second direction, and according to the graphic shapes of the magnetic tunnel junction 300 and the top electrode 800 having a positive magnetostriction coefficient, the stress of the passivation layer 900 is set to compressive stress, wherein the first direction is the short axis direction of the magnetic tunnel junction 300; for example, the length of the top electrode 800 in the first direction is represented by a; the second direction is the long axis direction of the magnetic tunnel junction 300, and the length of the top electrode 800 in the second direction is represented by b, then a<b, the passivation layer 900 tends to expand outward, causing the magnetic storage chip to warp and deform, and exerting a certain compressive strain on the top electrode 800 and the magnetic tunnel junction 300 below. Due to the influence of the shape of the top electrode 800, the compressive strains generated by the top electrode 800 along the first direction and the second direction are different, that is, the compressive strain generated by the top electrode 800 along the first direction is greater than the compressive strain generated along the second direction. For example, Figure 2 and Figure 6 In the figure, the number of arrows qualitatively indicates the difference in the compressive strain effect on the magnetic tunnel junction 300 in the first direction and the second direction. Figure 2 and Figure 6 It can be clearly seen that the number of arrows along the first direction is greater than the number of arrows along the second direction, and the size of the magnetic tunnel junction 300 in the first direction is reduced more than that in the second direction. Combined with the fact that the free layer of the magnetic tunnel junction 300 has a positive magnetostriction coefficient, the stress-induced magnetic anisotropy generated by the magnetic tunnel junction 300 in the second direction is enhanced, thereby being able to enhance the coercive field performance of the magnetic tunnel junction 300.

[0072] In other embodiments, the magnetostriction coefficient λ of the magnetic tunnel junction 300 is greater than 0, and the length a of the top electrode 800 in the first direction is greater than the length b in the second direction, that is, a>b. According to the positive magnetostriction coefficient of the magnetic tunnel junction 300 and the shape of the top electrode 800, the stress of the passivation layer 900 is set to tensile stress, wherein the first direction is the short axis direction of the magnetic tunnel junction 300; the passivation layer 900 with tensile stress tends to shrink outward, causing the magnetic storage chip to warp and deform, and exerts a certain tensile strain on the top electrode 800 and the magnetic tunnel junction 300 below. Due to the influence of the shape of the top electrode 800, the tensile strain generated by the top electrode 800 along the first direction and the second direction is different, that is, the tensile strain generated by the top electrode 800 along the first direction is less than the tensile strain generated along the second direction. For example, Figure 4 and Figure 8 In the figure, the number of arrows qualitatively indicates the difference in tensile strain applied to the magnetic tunnel junction 300 in the first direction and the second direction. Figure 4 and Figure 8It can be clearly seen that the number of arrows along the first direction is less than the number of arrows along the second direction. In this way, the size of the magnetic tunnel junction 300 in the second direction increases more than that in the first direction. Combined with the fact that the free layer of the magnetic tunnel junction 300 has a positive magnetostriction coefficient, the stress-induced magnetic anisotropy generated by the magnetic tunnel junction 300 in the second direction is enhanced, thereby being able to enhance the coercive field performance of the magnetic tunnel junction 300.

[0073] In some other embodiments, the magnetostriction coefficient λ of the magnetic tunnel junction 300 is less than 0, the length a of the top electrode 800 in the first direction is less than the length b in the second direction, that is, a<b, and according to the shape of the magnetic tunnel junction 300 and the top electrode 800 having a negative magnetostriction coefficient, the stress of the passivation layer 900 is set to tensile stress, wherein the first direction is the short axis direction of the magnetic tunnel junction 300; the second direction is the long axis direction of the magnetic tunnel junction 300; the passivation layer 900 with tensile stress tends to shrink outward, causing the magnetic storage chip to warp and deform, which has an impact on the top electrode 800 and the magnetic tunnel junction 300 below. 00 produces a certain tensile strain. Due to the influence of the shape of the top electrode 800, the tensile strains generated by the top electrode 800 along the first direction and the second direction are different, that is, the tensile strain generated by the top electrode 800 along the first direction is less than the tensile strain generated along the second direction. In this way, the size of the magnetic tunnel junction 300 in the second direction increases more than that in the first direction. Combined with the fact that the free layer of the magnetic tunnel junction 300 has a positive magnetostriction coefficient, the stress-induced magnetic anisotropy generated by the magnetic tunnel junction 300 in the second direction is enhanced, thereby enhancing the coercive field performance of the magnetic tunnel junction 300.

[0074] In some other embodiments, the magnetostriction coefficient λ of the magnetic tunnel junction 300 is less than 0, the length a of the top electrode 800 in the first direction is greater than the length b in the second direction, that is, a>b, and according to the shape of the magnetic tunnel junction 300 and the top electrode 800 having a negative magnetostriction coefficient, the stress of the passivation layer 900 is set to compressive stress, wherein the first direction is the short axis direction of the magnetic tunnel junction 300; the second direction is the long axis direction of the magnetic tunnel junction 300; the passivation layer 900 tends to expand outward, causing the magnetic storage chip to warp and deform, which has an impact on the top electrode 800 and the magnetic tunnel junction below. 300 produces a certain compressive strain effect. Due to the influence of the shape of the top electrode 800, the compressive strains generated by the top electrode 800 along the first direction and the second direction are different, that is, the compressive strain generated by the top electrode 800 along the first direction is greater than the compressive strain generated along the second direction. In this way, the size of the magnetic tunnel junction 300 in the first direction is reduced more than that in the second direction. Combined with the fact that the free layer of the magnetic tunnel junction 300 has a positive magnetostriction coefficient, the stress-induced magnetic anisotropy generated by the magnetic tunnel junction 300 in the second direction is enhanced, thereby enhancing the coercive field performance of the magnetic tunnel junction 300.

[0075] In some embodiments, Figures 1 to 8 As shown in the figure, a conductive hard mask structure 410 is arranged between the magnetic tunnel junction 300 and the top electrode 800 to achieve electrical conduction between the top electrode 800 and the magnetic tunnel junction 300 through the hard mask structure 410, and the hard mask structure 410 can also protect the upper surface of the magnetic tunnel junction 300.

[0076] In addition, if Figures 1 to 8 As shown in FIG. 6 , a dielectric protection layer 600 is further disposed on the sidewall of the magnetic tunnel junction 300 to protect the sidewall of the magnetic tunnel junction 300 .

[0077] In some embodiments, an interlayer dielectric layer 700 is further disposed on the dielectric protection layer 600, and an electrode hole 710 is disposed on the interlayer dielectric layer 700, and a top electrode 800 is disposed in the electrode hole 710, so that electrical conduction is achieved between the top electrode 800 and the magnetic tunnel junction 300 through the hard mask structure.

[0078] The embodiment of the present application also provides a method for preparing a magnetic memory, which is suitable for preparing the magnetic memory provided in the above embodiment.

[0079] Please combine Fig. 9 As shown, the method for preparing a magnetic memory provided in an embodiment of the present application includes the following steps:

[0080] S101: providing a substrate.

[0081] S102: forming a magnetic tunnel junction on the substrate.

[0082] S103: forming a top electrode on the magnetic tunnel junction, and performing patterning on the top electrode so that the top electrode is in a preset pattern, and the top electrode is electrically connected to the magnetic tunnel junction.

[0083] S104: forming a passivation layer on the top electrode; wherein the stress of the passivation layer is determined according to the shape of the top electrode and the magnetostriction coefficient of the magnetic tunnel junction, so as to increase the coercive field of the magnetic tunnel junction.

[0084] When implementing it, please combine Fig.10 As shown, first, a substrate 100 may be formed by a deposition process. The substrate 100 may be a semiconductor layer, and the material of the substrate 100 may include silicon, germanium, silicon carbide, silicon germanium, germanium on insulator, or silicon on insulator.

[0085] After the substrate 100 is formed, a conductive metal material is deposited on the substrate 100 to form a bottom electrode 200 on the substrate 100 , wherein the conductive metal material includes but is not limited to high-resistance materials such as TaN and TiN.

[0086] After forming a bottom electrode 200 on the substrate 100, an initial magnetic tunnel junction 300a is formed on the bottom electrode 200. Exemplarily, a free layer, a tunneling barrier layer, a reference layer and a pinned layer are sequentially stacked on the bottom electrode 200. The sequentially stacked free layer, the tunneling barrier layer, the reference layer and the pinned layer together form an initial magnetic tunnel junction 300a, and a hard mask layer 400 is formed on the initial magnetic tunnel junction 300a, wherein the hard mask layer 400 includes but is not limited to conductive films such as Ta, TaN, Co, Ti, TiN, and Ru.

[0087] Afterwards, please combine Fig.11 As shown, a photoresist 500 is coated on the hard mask layer 400, and the photoresist 500 is photolithographically processed to form a photoresist pattern, and the hard mask layer 400 is etched using the patterned photoresist 500 as a mask to form a hard mask structure 410, and the initial magnetic tunnel junction 300a is etched using the hard mask structure 410 as a mask to form a magnetic tunnel junction 300 (as shown in FIG. Fig.12 ).

[0088] The magnetic tunnel junction 300 may be elliptical, circular, rectangular or square, and may be adaptively designed according to actual needs, without limitation herein. The following description will take the elliptical magnetic tunnel junction 300 as an example.

[0089] Please combine Fig.13 As shown, after the magnetic tunnel junction 300 is formed, a dielectric protection layer 600 can be deposited on the hard mask structure 410 through deposition processes such as chemical vapor deposition (CVD) and physical vapor deposition (PVD). The dielectric protection layer 600 provides good protection for the surface of the bottom electrode 200, the exposed sidewalls of the magnetic tunnel junction 300, and the exposed surface of the hard mask structure 410.

[0090] Please combine Fig.14 As shown, after the dielectric protection layer 600 is formed, a deposition process such as CVD or PVD is used to deposit an interlayer dielectric layer 700 on the dielectric protection layer 600, and then a chemical mechanical polishing process is used to planarize the surface of the interlayer dielectric layer 700.

[0091] Please combine Fig.15 As shown, photolithography and etching are performed on the planarized interlayer dielectric layer 700 to form an electrode hole 710 , where the electrode hole 710 exposes the hard mask structure 410 .

[0092] Please combine Fig.16As shown, after the electrode hole 710 is formed, a deposition process such as CVD or PVD is used to deposit the top electrode 800 material in the electrode hole 710 to form an initial top electrode 800, and the initial top electrode 800 is patterned to form a top electrode 800 with a preset pattern, and the top electrode 800 is electrically connected to the magnetic tunnel junction 300.

[0093] After forming the top electrode 800 with a preset pattern, a dielectric material with high stress is deposited on the top electrode 800 to form a passivation layer 900 (eg, Figure 1 As shown in ), in this way, the stress properties and size of the passivation layer 900 can be set according to the magnetostriction coefficient of the magnetic tunnel junction 300 and the shape of the top electrode 800.

[0094] It should be noted that the stress properties and stress magnitude of the passivation layer 900 are set based on the magnetostriction coefficient of the magnetic tunnel junction 300 and the shape of the top electrode 800. Therefore, when the magnetostriction coefficient of the magnetic tunnel junction 300 is determined, the stress shape and stress magnitude of the passivation layer 900 are adapted to the graphic shape of the top electrode 800.

[0095] In some embodiments, please combine Figure 1 As shown, the graphic shape of the top electrode 800 is a top electrode 800 extending vertically, that is, the length a of the top electrode 800 in the first direction is smaller than the length b in the second direction, wherein the first direction is the short axis direction of the magnetic tunnel junction 300, and the second direction is the long axis direction of the magnetic tunnel junction 300; thus, the passivation layer 900 formed on the top electrode 800 is configured to have compressive stress.

[0096] Another example, please combine Figure 3 As shown, the graphic shape of the top electrode 800 is a top electrode 800 extending in the transverse direction, wherein the length a of the top electrode 800 in the first direction is greater than the length b in the second direction, wherein the first direction is the short axis direction of the magnetic tunnel junction 300; thus, the passivation layer 900 formed on the top electrode 800 is configured to have tensile stress.

[0097] The material of the passivation layer 900 includes at least one of silicon nitride (SiN) and silicon oxide (SiO).

[0098] It should be noted that, in the magnetic memory 10 provided in the embodiment of the present application, only the shape of the top electrode 800 is limited, and the shape of the magnetic tunnel junction 300 can be any one of an ellipse, a circle, a rectangle, a square, etc. When only the shape of the magnetic tunnel junction 300 in the magnetic memory 10 changes and other structures remain unchanged, then in the preparation process of the magnetic memory 10, the preparation method is the same as the preparation method provided above, and will not be repeated here.

[0099] In summary, the magnetic memory and the preparation method thereof provided in the embodiments of the present application, by setting a top electrode in a preset pattern on the magnetic tunnel junction, and setting a passivation layer on the top electrode in combination with the shape of the top electrode, so that the stress of the passivation layer is determined according to the shape of the top electrode and the magnetostriction coefficient of the magnetic tunnel junction. In this way, on the one hand, the passivation layer and the top electrode can be used to transfer anisotropic stress to induce the in-plane magnetic anisotropy of the magnetic tunnel junction, thereby enhancing the coercive field performance of the magnetic tunnel junction, thereby improving the magnetic resistance of the magnetic memory and enhancing the stability of data storage; or, it is also possible to reduce the size of the magnetic tunnel junction while ensuring that the coercive field performance of the magnetic tunnel junction is not reduced, thereby improving the layout density of the magnetic memory; on the other hand, the coercive field Hc of the magnetic tunnel junction and the write current of the bottom electrode can be decoupled from each other, so that while maintaining a high coercive field performance, the power consumption can be further reduced; on the other hand, there is no need to add additional process steps, the process is simple, and the process cost can be reduced.

[0100] The various embodiments or implementation methods in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referenced to each other.

[0101] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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 application.

Claims

1. A magnetic memory, characterized in that: include: A substrate, a magnetic tunnel junction disposed on the substrate, a top electrode disposed on the magnetic tunnel junction, and a passivation layer disposed on the top electrode; The top electrode is electrically connected to the magnetic tunnel junction, the top electrode is configured to be in a preset pattern, and the stress of the passivation layer is set according to the shape of the top electrode and the magnetostriction coefficient of the magnetic tunnel junction; The length of the top electrode in the first direction is different from that in the second direction, and the stress is transferred by the passivation layer and the top electrode to induce the in-plane magnetic anisotropy of the magnetic tunnel junction to increase the coercive field of the magnetic tunnel junction.

2. The magnetic memory according to claim 1, characterized in that The magnetostriction coefficient of the magnetic tunnel junction is greater than zero; The length of the top electrode in the first direction is smaller than the length in the second direction, the stress of the passivation layer is set to compressive stress, the first direction is the short axis direction of the magnetic tunnel junction; the second direction is the long axis direction of the magnetic tunnel junction.

3. The magnetic memory according to claim 1, characterized in that: The magnetostriction coefficient of the magnetic tunnel junction is greater than zero; The length of the top electrode in the first direction is greater than the length in the second direction, the stress of the passivation layer is set to tensile stress, the first direction is the short axis direction of the magnetic tunnel junction; the second direction is the long axis direction of the magnetic tunnel junction.

4. The magnetic memory according to claim 1, characterized in that: The magnetostriction coefficient of the magnetic tunnel junction is less than zero; The length of the top electrode in the first direction is smaller than the length in the second direction, the stress of the passivation layer is set to tensile stress, the first direction is the short axis direction of the magnetic tunnel junction; the second direction is the long axis direction of the magnetic tunnel junction.

5. The magnetic memory according to claim 1, characterized in that: The magnetostriction coefficient of the magnetic tunnel junction is less than zero; The length of the top electrode in the first direction is greater than the length in the second direction, the stress of the passivation layer is set to compressive stress, the first direction is the short axis direction of the magnetic tunnel junction; the second direction is the long axis direction of the magnetic tunnel junction.

6. The magnetic memory according to any one of claims 1 to 5, characterized in that: The outline shape of the magnetic tunnel junction includes at least one of an ellipse, a circle, a rectangle, and a square.

7. The magnetic memory according to any one of claims 1 to 5, characterized in that: The passivation layer includes at least one of a silicon nitride layer and a silicon oxide layer.

8. A method for preparing a magnetic memory, characterized in that: The preparation method comprises: providing a substrate; forming a magnetic tunnel junction on the substrate; forming a top electrode on the magnetic tunnel junction, and performing patterning on the top electrode so that the top electrode is in a preset pattern, and the top electrode is electrically connected to the magnetic tunnel junction; forming a passivation layer on the top electrode; wherein the stress of the passivation layer is determined according to the shape of the top electrode and the magnetostriction coefficient of the magnetic tunnel junction; The length of the top electrode in the first direction is different from that in the second direction, and the stress is transferred by the passivation layer and the top electrode to induce the in-plane magnetic anisotropy of the magnetic tunnel junction to increase the coercive field of the magnetic tunnel junction.

9. The method for preparing a magnetic memory according to claim 8, characterized in that: Before forming a top electrode on the magnetic tunnel junction, the method comprises: forming a dielectric protection layer on the magnetic tunnel junction; forming an interlayer dielectric layer on the dielectric protection layer; performing a planarization process on the surface of the interlayer dielectric layer; Electrode holes are formed on the interlayer dielectric layer after the planarization process.

10. The method for preparing a magnetic memory according to claim 9, characterized in that: Forming a passivation layer on the top electrode specifically includes: At least one of a silicon oxide material and a silicon nitride material is deposited on the top electrode to form a passivation layer according to the shape of the top electrode and the magnetostriction coefficient of the magnetic tunnel junction.

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