Magnetic device, magnetic storage device using the same, and method for providing the same

Abstract

The present invention describes a magnetic device, a memory using the magnetic device, and a method for providing the magnetic device. The magnetic device includes a magnetic junction and a mixed cap layer adjacent to the magnetic junction. The mixed cap layer includes an insulating layer, a discontinuous oxide layer, and a noble metal layer. The discontinuous oxide layer is located between the insulating layer and the noble metal layer. The insulating layer is located between the magnetic junction and the noble metal layer. In one aspect, the magnetic junction includes a reference layer, a nonmagnetic separation layer that may be a tunnel barrier layer, and a free layer.

Description

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS]

[0002] This application claims the benefit of provisional patent application number 62 / 637,586 filed on March 2, 2018 and entitled PERPENDICULAR MAGNETIC JUNCTION / MAGNETIC CELL HAVING HYBRID OXIDE AND NOBLE METAL LAYERS, which is assigned to the assignee of the present application and is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a magnetic device, a memory using the magnetic device, and a method for providing the magnetic device. Background Art

[0004] Magnetic memories, especially magnetic random access memories (MRAM), are gaining increasing attention due to their potential for high read / write speeds, excellent durability, non-volatility, and low power consumption during operation. Magnetic random access memories can use magnetic materials as information recording media to store information. One type of magnetic random access memory is spin transfer torque magnetic random access memory (STT-MRAM). Spin transfer torque magnetic random access memory utilizes a magnetic junction that is at least partially written by a current driven through the magnetic junction. The spin polarized current driven through the magnetic junction exerts a spin torque on the magnetic moment in the magnetic junction. Therefore, a layer having a magnetic moment responsive to the spin torque can be switched to a desired state.

[0005] For example, a conventional magnetic tunnel junction (MTJ) may be used in a conventional spin transfer torque magnetic random access memory. A conventional magnetic tunnel junction uses a seed layer, may include a cap layer, and may include an antiferromagnetic (AFM) layer to fix the magnetization of a reference layer. A conventional magnetic tunnel junction includes a seed layer, a reference layer, a tunneling barrier layer, a free layer, and a cap layer. A bottom contact located below the magnetic tunnel junction and a top contact located on the magnetic tunnel junction may be used to drive current through the magnetic tunnel junction in a current-perpendicular-to-plane (CPP) direction. The reference layer and the free layer are magnetic. The magnetization of the reference layer is fixed or pinned in a specific direction. The free layer has a magnetization that can be changed. The free layer and the reference layer may be a single layer or include multiple layers.

[0006] To switch the magnetization of the free layer, a current is driven in a direction perpendicular to the plane. When sufficient current is driven from the top contact to the bottom contact, the magnetization of the free layer can be switched to be parallel to the magnetization of the bottom reference layer. When sufficient current is driven from the bottom contact to the top contact, the magnetization of the free layer can be switched to be antiparallel to the magnetization of the bottom reference layer. The difference in magnetic configuration corresponds to different magnetic resistances, and therefore to different logical states (e.g., logical "0" and logical "1") of a conventional magnetic tunnel junction.

[0007] Research into magnetic memories is ongoing because of their potential for use in a variety of applications. It is desirable to scale magnetic junctions to smaller area sizes (e.g., for increased storage density) without significantly degrading magnetic and electrical properties. For example, it is desirable to scale nonvolatile magnetic memories to less than forty nanometers. Operating temperatures for high temperature operating applications and magnetic memories are typically relatively high, e.g., above one hundred degrees Celsius. It is desirable to scale the magnetic thermal stability factor Δ and thus the effective magnetic anisotropy constant K to a value greater than 100 degrees Celsius. ueff Keep it high. Current magnetic junctions cannot be scaled to such sizes without adversely affecting one or more of the saturation magnetization, exchange stiffness, damping, and / or effective magnetic anisotropy constants. Furthermore, even at current sizes, it is desirable to improve performance.

[0008] Therefore, there is a need for a method and system that can improve the performance and scalability of magnetic devices and electronic devices in which such magnetic devices are used. The method and system described herein meet this need. Summary of the invention

[0009] The present invention describes a magnetic device, a memory using the magnetic device, and a method for providing the magnetic device. The magnetic device includes a magnetic junction and a hybrid cap layer adjacent to the magnetic junction. The hybrid cap layer includes an insulating layer, a discontinuous oxide layer, and a noble metal layer. The discontinuous oxide layer is located between the insulating layer and the noble metal layer. The insulating layer is located between the magnetic junction and the noble metal layer. In one aspect, the magnetic junction includes a reference layer, a non-magnetic spacer layer that may be a tunnel barrier layer, and a free layer. In this aspect, the hybrid cap layer may be adjacent to the free layer.

[0010] When a magnetic junction is used with a hybrid cap layer, it can have improved performance. More specifically, the magnetic junction can enjoy an enhanced effective magnetic anisotropy constant without significantly reducing saturation magnetization, resistance area product, tunneling magnetoresistance (TMR), and / or damping constant. Therefore, performance can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 An exemplary embodiment of a magnetic device including a magnetic junction and a hybrid cap layer is depicted.

[0012] Figure 2 An exemplary embodiment of a hybrid cap layer that may be used in conjunction with a magnetic junction is depicted.

[0013] Figure 3 An exemplary embodiment of a magnetic device including a magnetic junction and a hybrid cap layer is depicted.

[0014] FIG. 4A to FIG. 4F The properties of an exemplary embodiment of a magnetic junction are shown as a function of the thickness of the insulating layer.

[0015] Figure 5 An exemplary embodiment of a memory utilizing a magnetic junction and a hybrid cap layer in a memory element of a memory cell is shown.

[0016] Figure 6 is a flow chart illustrating an exemplary embodiment of a method for providing a magnetic device that can be used in a magnetic device that is programmable using spin transfer torque and includes a hybrid cap layer.

[0017] Figure 7is a flow chart illustrating an exemplary embodiment of a method for providing a magnetic device that can be used in a magnetic device that is programmable using spin transfer torque and includes a hybrid cap layer.

[0018] Figure 8 is a flow chart depicting an exemplary embodiment of a method for providing a hybrid cap layer.

[0019] [Explanation of Symbols]

[0020] 100, 100A, 212: Magnetic device

[0021] 101: Substrate

[0022] 102: Seed layer

[0023] 103, 103A: Magnetic junction

[0024] 110, 110A: Reference layer

[0025] 111, 113, 117, 131, 151: magnetic moment

[0026] 112: Bottom ferromagnetic layer / ferromagnetic layer

[0027] 114: Non-magnetic layer

[0028] 116: Top ferromagnetic layer / ferromagnetic layer

[0029] 120: Non-magnetic separator layer / crystalline MgO tunnel barrier layer

[0030] 120A: Tunnel barrier layer

[0031] 130: Free layer

[0032] 140, 140A: Mixed top cover

[0033] 142: Insulation layer

[0034] 143: Oxide island / island / MgAl and part of Mo oxide island / MgAl and part of Nb oxide island / MgAl and part of Zr oxide island

[0035] 144A: Discontinuous oxide layer

[0036] 145: Metal Island / Island / Mo Island / Nb Island / Zr Island

[0037] 146: Precious metal layer

[0038] 150: Polarization Enhanced Layer (PEL)

[0039] 180, 182, 184, 190, 192, 194: Curve graph

[0040] 200: Memory / Magnetic Memory

[0041] 202, 206: Read / write column select driver

[0042] 203: Bit line

[0043] 204: word line selection driver

[0044] 205: Word Line

[0045] 210: Magnetic storage unit / cell

[0046] 214: Select device

[0047] 300, 310, 330: Method

[0048] 302, 304, 312, 314, 316, 318, 332, 334, 336, 338: Steps

[0049] t1, t2, t3, t4, t5: thickness DETAILED DESCRIPTION

[0050] Exemplary embodiments relate to magnetic junctions that can be used in magnetic devices (e.g., magnetic memories) and devices using such magnetic junctions. Magnetic memories may include spin transfer torque magnetic random access memory (STT-MRAM), spin-orbit torque (SOT) devices, logic or other devices using spin transfer torque or spin-orbit torque magnetic junctions, and / or other electronic devices. Such electronic devices include, but are not limited to, mobile phones, smart phones, tablet computers, laptop computers, and other portable and non-portable computing devices. The following description is presented to enable a person of ordinary skill in the art to make and use the present invention, and the following description is provided in the context of a patent application and its requirements. Various modifications to the exemplary embodiments and general principles and features described herein will be apparent. The exemplary embodiments are primarily described with respect to specific methods and systems provided in specific embodiments. However, the methods and systems will also function effectively in other embodiments. Phrases such as "exemplary embodiments", "one embodiment", and "another embodiment" may refer to the same or different embodiments and multiple embodiments. The embodiments will be described with respect to systems and / or devices having certain components. However, the system and / or device may include more or fewer components than those shown in the figures, and the arrangement and type of components may vary without departing from the scope of the invention. The exemplary embodiments will also be described in the context of a specific method with certain steps. However, the methods and systems will also work effectively for other methods with different and / or additional steps and steps in different orders, which do not contradict the exemplary embodiments. Therefore, the present invention is not intended to be limited to the embodiments shown in the figures, but is in the widest range consistent with the principles and features described herein.

[0051] The present invention describes a magnetic device, a memory using the magnetic device, and a method for providing the magnetic device. The magnetic device includes a magnetic junction and a mixed cap layer adjacent to the magnetic junction. The mixed cap layer includes an insulating layer, a discontinuous oxide layer, and a noble metal layer. The discontinuous oxide layer is located between the insulating layer and the noble metal layer. The insulating layer is located between the magnetic junction and the noble metal layer. In one aspect, the magnetic junction includes a reference layer, a nonmagnetic separation layer that may be a tunnel barrier layer, and a free layer.

[0052] The exemplary embodiments are described in the context of specific methods, magnetic junctions with certain components, and magnetic memories. A person of ordinary skill in the art will readily recognize that the present invention is consistent with the use of magnetic junctions and magnetic memories with other and / or additional components and / or other features that are not inconsistent with the present invention. The methods and systems are also described in the context of the current understanding of the spin transfer phenomenon, magnetic anisotropy, and other physical phenomena. Therefore, a person of ordinary skill in the art will readily recognize that the theoretical explanation of the behavior of the methods and systems is based on the current understanding of spin transfer, magnetic anisotropy, and other physical phenomena. However, the methods and systems described herein do not rely on a specific physical explanation. A person of ordinary skill in the art will also readily recognize that the methods and systems are described in the context of a structure having a specific relationship with a substrate. A person of ordinary skill in the art will readily recognize that the methods and systems are consistent with other structures. In addition, the methods and systems are described in the context of certain layers being composite and / or simple layers. However, a person of ordinary skill in the art will readily recognize that the layers may have another structure. In addition, the methods and systems are described in the context of magnetic junctions and / or substructures having specific layers. A person of ordinary skill in the art will readily recognize that magnetic junctions and / or substructures having additional and / or different layers that are not inconsistent with the methods and systems may also be used. In addition, certain components are described as magnetic, ferromagnetic, and ferrimagnetic. The term "magnetic" as used herein may include ferromagnetic, ferrimagnetic, or similar structures. Therefore, the terms "magnetic" or "ferromagnetic" as used herein include, but are not limited to, ferromagnets and ferrimagnets. The term "in-plane" as used herein is substantially in the plane of one or more of the layers of the magnetic junction or parallel to the plane of one or more of the layers of the magnetic junction. In contrast, "perpendicular" and "perpendicular-to-plane" correspond to directions that are substantially perpendicular to one or more of the layers of the magnetic junction. The methods and systems are also described in the context of certain alloys. Unless otherwise indicated, if specific concentrations of alloys are not mentioned, any stoichiometry that is not inconsistent with the described methods and systems may be used.

[0053] Figure 1 An exemplary embodiment of a magnetic device 100 including a magnetic junction 103 and a hybrid cap layer 140 is shown. The magnetic device 100 may be used in a magnetic memory or other device that may be programmed using spin transfer torque and / or spin orbit torque. Figure 1The drawings are not to scale and not all components may be shown.The magnetic device 100 may therefore be used in a variety of electronic devices.

[0054] The magnetic junction 103 can be programmed using spin-orbit torque (SOT) and / or spin transfer torque (STT). In the illustrated embodiment, the magnetic junction 103 includes a reference layer 110 having a magnetic moment 111, a non-magnetic spacer layer 120, and a free layer 130 having a magnetic moment 131. The substrate 101 on which the magnetic junction 103 is formed is present below the seed layer and is shown for clarity. An optional seed layer 102 is also shown. The bottom contact and top contact are not shown, but may be formed. There may be other layers such as a coupling layer, a polarization enhancement layer (PEL), and an antiferromagnetic (AFM) layer and / or other layers. However, these layers are not shown for simplicity. As may be seen in Figure 1 As can be seen in FIG. 1 , the reference layer 110 of the magnetic junction 103 is closest to the substrate 101. The magnetic junction 103 is a bottom pinned magnetic junction. In other embodiments, other configurations are possible.

[0055] The free layer 130 may have a high perpendicular magnetic anisotropy (PMA). In such an embodiment, the free layer 130 has a perpendicular magnetic anisotropy energy that is greater than the free layer out-of-plane demagnetization energy. Therefore, the magnetic moment 131 is stable perpendicular to the plane. As can be inferred from the double-headed arrow, the free layer magnetic moment 131 can point in the direction of Figure 1 At the top of the page and when pointing to Figure 1. In an alternative embodiment, the magnetic moment 131 may be stably located in a plane. The free layer 130 is depicted as a single layer. However, in other embodiments, the free layer 130 may be a multilayer having different saturation magnetizations and crystallization temperatures. The free layer 130 may be a synthetic antiferromagnet (SAF) including a plurality of ferromagnetic layers interlaced with and sandwiching one or more nonmagnetic layers. For example, the free layer 130 may include two ferromagnetic layers separated by a nonmagnetic layer, such as a Ru, Ir, Mo, or W layer. The thickness of the nonmagnetic layer may be selected so that the ferromagnetic layers are antiferromagnetically coupled via Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling or magnetostatic interaction. Alternatively, the thickness of the nonmagnetic layer may be selected for ferromagnetic coupling. In other embodiments, the free layer 130 may be another multilayer and / or may have layers coupled in another manner. In some embodiments, the free layer may include or consist of FeB, FeB-X, FeCoB, FeCoB-X, Fe without B, Fe-X, FeCo, and FeCo-X, where X is selected from Be, Ni, Mo, Mg, Zr, Ta, V, Cr, W, Hf, Nb, and Tb. As used herein, alloys such as FeB refer to Fe 1-y B y An alloy of y, where 0≤y<0.5. For simplicity, the exact stoichiometry is not specified. Other or additional alloys and / or multiple layers may be used in other embodiments.

[0056] The free layer 130 has a magnetic moment 131 that can be changed and can therefore be used to store data. The magnetic junction 103 is also configured to allow the free layer magnetic moment 131 to switch between stable magnetic states using a write current through the magnetic junction 103 and / or using a current through a neighboring line (not shown) with high spin orbit coupling. Therefore, when a write current is driven through the magnetic junction 103 in a direction perpendicular to the plane (CPP) and / or through the spin orbit torque, the free layer 130 can be switched using the spin transfer torque. Depending on the direction of the write current, the free layer 130 can be programmed to different states. The direction of the magnetic moment 131 of the free layer 130 can be read by driving a read current through the magnetic junction 103. This read current is less than the spin transfer write current and is insufficient to switch the direction of the magnetic moment.

[0057] The non-magnetic spacer layer 120 may be a tunnel barrier layer. For example, the non-magnetic spacer layer 120 may be a crystalline MgO tunnel barrier layer having a (100) crystal orientation. Such a non-magnetic spacer layer 120 may not only enhance the tunnel magnetoresistance (TMR) of the magnetic junction 103, but also increase the perpendicular magnetic anisotropy of the free layer 130. The crystalline MgO tunnel barrier layer 120 may have a thickness of at least eight angstroms but not more than fifteen angstroms. For example, the crystalline MgO tunnel barrier layer 120 may nominally be at least ten angstroms thick but not more than twelve angstroms thick. However, other thicknesses and / or other barrier layers are also possible. The non-magnetic spacer layer 120 may also be considered to act as a seed layer for the free layer 130. In alternative embodiments, the non-magnetic spacer layer 120 may have another structure including, but not limited to, a conductive layer.

[0058] The reference layer 110, also referred to as a pinned layer, has a perpendicular magnetic anisotropy energy greater than the out-of-plane demagnetization energy. Therefore, the magnetic moment 111 is stably perpendicular to the plane. The reference layer 110 is shown as a single layer. However, in other embodiments, the reference layer 110 may be a multilayer. For example, the reference layer 110 may be a synthetic antiferromagnet (SAF) including a plurality of ferromagnetic layers, which are interlaced with and sandwich one or more non-magnetic layers. For example, the reference layer 110 may include two ferromagnetic layers separated by a non-magnetic layer, such as a Ru or Ir layer. The thickness of the Ru or Ir layer may be selected so that the ferromagnetic layers are antiferromagnetically coupled via de Man-Kittel-Katsuko-Yoshida (RKKY) coupling. In other embodiments, other multilayers may be used. For example, the reference layer 110 may include a Co-Pt layer and / or a Co-Ir layer. For example, the reference layer 110 may be or may include a Co / Pt multilayer. In such a multilayer, one or more repetitions of a Co / Pt bilayer ([Co / Pt]n, where n≥1) may be used. In some embodiments, the reference layer 110 may be or may include a Co / Ir multilayer. Such a multilayer has one or more repetitions of a Co / Ir bilayer ([Co / Ir]n, where n≥1). In some embodiments, the optional pinning layer may be an AFM layer or multilayer that pins the magnetization through an exchange-bias interaction. However, in other embodiments, the optional pinning layer may be omitted, or another structure may be used. In the embodiment shown, the magnetic moment 111 of the reference layer 110 is pinned by the magnetic anisotropy of the reference layer 110.

[0059] The hybrid cap layer 140 is adjacent to the magnetic junction 103 and can be used to improve the performance of the magnetic junction 103. In the illustrated embodiment, the hybrid cap layer 140 is adjacent to the magnetic junction 103 or shares an interface with the magnetic junction 103. In addition, in the illustrated embodiment, the hybrid cap layer 140 is adjacent to the free layer 130. The hybrid cap layer 140 includes an insulating layer, a discontinuous oxide layer and a noble metal layer. The discontinuous oxide layer is located between the insulating layer and the noble metal layer. The insulating layer is located between the magnetic junction 103 and the noble metal layer. The insulating layer and the noble metal layer are oxygen barrier layers. The discontinuous oxide layer can be used to enhance the migration of boron from the free layer 130 to the hybrid cap layer 140, which can form a tunnel interface containing a relatively small amount of boron between the free layer 130 and the non-magnetic separation layer 120.

[0060] Figure 2 An exemplary embodiment of a hybrid cap layer 140A is depicted. Figure 2 Not drawn to scale. Figure 1 to Figure 2 , the hybrid cap layer 140 and 140A each include an insulating layer 142, a discontinuous oxide layer 144A and a noble metal layer 146. As described above, the noble metal layer 146 is an oxygen barrier layer. Therefore, the material for the noble metal layer 146 is selected to be an oxygen blocker. In some embodiments, the noble metal layer 146 includes at least one of Ru, Pt, Ir, Rh, Pd and Os. In some embodiments, the noble metal layer 146 is composed of Ru, Pt, Ir, Rh, Pd, Os or an alloy including one or more of the above. The noble metal layer 146 also has a thickness of at least ten angstroms and not more than one hundred angstroms. In some embodiments, the noble metal layer 146 has a thickness of at least fifteen angstroms and not more than eighty angstroms. In some such embodiments, the thickness of the noble metal layer 146 is at least twenty angstroms and not more than sixty angstroms. In some cases, the improvement provided by the noble metal layer 146 is saturated at a thickness of twenty angstroms. However, in other embodiments, it may be other thicknesses.

[0061] The insulating layer 142 is closest to the magnetic junction 103. The insulating layer 142 is amorphous when deposited. In some embodiments, the insulating layer 142 includes or consists of at least one of the following: magnesium oxide-aluminum oxide (MgO-Al 2 O 3 ), magnesium alumina (MgAl 2 O 4 ), titanium oxide doped magnesium oxide (TiO 2 -doped MgO) and zirconium oxide doped MgO (ZrO 2 -doped MgO). In one embodiment, the insulating layer 142 is composed of magnesium aluminum oxide. Using a material that is more amorphous and denser than MgO (e.g., MgAl 2 O4 ) can protect the free layer 130 from oxidation and diffusion.

[0062] A discontinuous oxide layer 144A is also shown. The discontinuous oxide layer 144A can be formed by depositing a discontinuous metal layer and performing an oxidation step. Therefore, a metal island can be formed and then oxidized. In the discontinuous oxide layer 144A, the area where the metal island 145 is deposited is retained, and other areas without the metal island 145 have been oxidized to MgAl oxide from the oxygen-deficient insulating layer 142. The thickness of the discontinuous metal layer and the oxidation step can control the unique microstructure of the discontinuous oxide layer. However, these oxides formed by different oxygen affinities are unstable during the annealing process. When a Ta or Mg layer with a high oxygen affinity is deposited on the top of the discontinuous layer, these oxygen atoms are transferred to the Ta or Mg layer via a solid-state oxidation process. A discontinuous oxide layer is not formed. However, when a noble metal layer with a much smaller oxygen affinity is deposited on the top of the discontinuous layer, the oxygen atoms captured between the noble metal layer 146 and the insulating layer 142 are retained. During the annealing process, the trapped oxygen atoms on the discontinuous oxide regions have a strong boron affinity. This preferred extraction of boron from the free layer 130 to the hybrid cap layer 140 provides a gradient of boron concentration along the vertical direction; so that a higher boron content is close to the hybrid cap layer 140, and a much lower boron content is close to the nonmagnetic separation layer 120. This unique process can enhance perpendicular magnetic anisotropy and improve performance by providing a better tunnel interface with less boron contamination. Although the metal island 145 is depicted as being larger than the oxide island 143, this is not necessarily the case. In addition, the shape and aspect ratio of islands 143 and 145 are not intended to represent a specific embodiment, but are only for explanation purposes. In addition, the size of the oxide island 143 and the metal island 145 can be varied rather than as Figures 2 to 3 144A. In some embodiments, the metal used in the discontinuous oxide layer 144A includes at least one of Mo, W, Nb and Zr. In some embodiments, only one of the metals Mo, W, Nb and Zr is used. Therefore, the oxide island 143 may include one or more of molybdenum oxide, tungsten oxide, niobium oxide and zirconium oxide. In some embodiments, the oxide island 143 may include Mg-Al oxide, Mg-Ti oxide and Mg-Zr oxide from the oxygen-deficient insulating layer 142. In some embodiments, the discontinuous oxide layer 144A has a thickness of at least 0.5 angstroms and no greater than three angstroms.

[0063] Figure 3 An exemplary embodiment of a magnetic device 100A that can be used in a magnetic device (e.g., a magnetic memory that can be programmed using spin transfer torque) is shown. For clarity, Figure 3It is not drawn to scale and not all components may be shown. Magnetic device 100A is similar to magnetic device 100. Therefore, similar components have similar references.

[0064] The magnetic device 100A includes a magnetic junction 103A and a hybrid cap layer 140A. In alternative embodiments, other hybrid cap layers may be present. The magnetic junction 103A is a bottom pinned magnetic junction that includes a reference layer 110A, a polarization enhancement layer (PEL) 150 incorporated into the reference layer 110A, a nonmagnetic spacer layer as a tunnel barrier layer 120A, and a free layer 130 having a magnetic moment 131. The reference layer 110A, the tunnel barrier layer 120A, and the free layer 130 having a magnetic moment 131 are similar to Figure 1 1 , a reference layer 110, a nonmagnetic spacer layer 120, and a free layer 130 having a magnetic moment 131. An optional seed layer 102 and a substrate 101 are also shown.

[0065] The structures, functions, and materials of the reference layer 110A, the tunnel barrier layer 120A, and the free layer 130 used in the magnetic junction 103A are similar to those of the reference layer 110, the nonmagnetic spacer layer 120, and the free layer 130 used in the magnetic junction 103. For example, the tunnel barrier layer 120A may be a crystalline MgO barrier layer, and the free layer 130 may include at least one of FeB, FeB-X, FeCoB, FeCoB-X, Fe without B, Fe-X, FeCo, and FeCo-X, where X is selected from Be, Ni, Mo, Mg, Zr, Ta, V, Cr, W, Hf, Nb, and Tb. However, in the illustrated embodiment, the reference layer 110A is a synthetic antiferromagnet (SAF). Therefore, the reference layer 110A includes a bottom ferromagnetic layer 112 separated by a nonmagnetic layer 114 (e.g., Ru or Ir), and a top ferromagnetic layer 116 and a polarization enhancement layer (PEL) 150. The ferromagnetic layer 112 , the ferromagnetic layer 116 , and the polarization enhancing layer 150 have magnetic moments 113 , 117 , and 151 , respectively, and are antiferromagnetically coupled.

[0066] The reference layer 110A includes a polarization enhancement layer 150. The reference layer 110A may include or consist of the following two parts: a polarization enhancement layer and a texture breaking layer. The texture breaking layer is amorphous to break the face centered cubic (FCC) texture (111) from the crystalline ferromagnetic layer 112 and the ferromagnetic layer 116. The texture breaking layer may be a single layer, such as Ta, Mo, and W. It may be a bilayer or a trilayer, such as Ta / CoFeB and Ta / CoFeB / Ta. The polarization enhancement layer is a ferromagnetic layer with a body centered cubic (BCC) structure to enhance spin polarization before the tunnel barrier layer 120A. The polarization enhancement layer may be a single layer or multiple layers. In some embodiments, the polarization enhancement layer contains B and at least one of Co and Fe. For example, the PEL may include (CoFe) (1-x) B x layer and / or Fe (1-x) B x layer. In these embodiments, where 0.2 < x. In some such embodiments, x ≤ 0.6. However, in alternative embodiments, other stoichiometries and / or other materials may be used.

[0067] The hybrid capping layer 140A is also shown. The hybrid capping layer 140A is similar to Figure 2 the hybrid capping layer shown. Thus, the hybrid capping layer 140A includes an insulating layer 142 that may serve as an oxygen barrier and a noble metal layer 146. Additionally, a discontinuous oxide layer 144A with oxide islands 143 and metal islands 145 is shown. The materials used in layer 142, layer 144A, and layer 146 may be similar to the above materials. In some embodiments, the insulating layer 142 is MgAl 2 O 4 layer, the discontinuous oxide layer 144A includes Mo islands 145 and MgAl and partial Mo oxide islands 143, and the noble metal layer 146 is Ru. In other embodiments, the insulating layer 142 is MgAl 2 O 4 layer, the discontinuous oxide layer 144A includes Nb islands 145 and MgAl and partial Nb oxide islands 143, and the noble metal layer 146 is Ru. In other embodiments, the insulating layer 142 is MgAl 2 O 4 layer, the discontinuous oxide layer 144A includes Zr islands 145 and MgAl and partial Zr oxide islands 143, and the noble metal layer 146 is Ru. However, other materials such as the above materials may be used.

[0068] The magnetic junction 103 / 103A may have improved performance. The hybrid cap layer 140 / 140A may increase the effective magnetic anisotropy constant K ueff , the saturation magnetization, damping constant, resistance-area product (RA) and TMR of the magnetic junction 103 / 103A will not be substantially reduced. This is especially true for the magnetic junction 103 / 103A using a MgO barrier layer as the nonmagnetic spacer layer 120 / 120A. FIG. 4A to FIG. 4F The properties of an exemplary embodiment of a magnetic junction are shown as a function of the thickness of the insulating layer. Graphs 180, 182, and 184 show how coercivity (Hc), TMR, and RA vary with the selected noble metal for the noble metal layer 146. Graphs 190, 192, and 194 show how Hc, TMR, and RA vary with the thickness of the Ru noble metal layer 146 from t 1 (5 angstroms) to t 5 (60 angstroms) may vary in thickness t1, t2, t3, t4, t5. However, in other embodiments, other thicknesses may be used. FIG. 4A to FIG. 4F As can be seen in the graph, the coercivity can be significantly improved while maintaining TMR and RA. In addition, the noble metals Pt, Ir, and Ru show improvements over Mg and MgO. In addition, this effect may saturate for the thickness of the noble metal layer 146. For example, a magnetic junction with a traditional MgO or Ta oxide cap layer may have a coercivity of approximately 0.1 erg / cm 2 To 0.3erg / cm 2 The free layer K ueff In contrast, in some embodiments, the K of the free layer 130 in the magnetic device 100 using the hybrid cap layer 140 / 140A is ueff Can be about 0.7erg / cm 2 Therefore, the magnetic anisotropy is significantly enhanced. RA, TMR and damping constant can be substantially maintained. For example, in some embodiments, RA can be 10Ωμm 2 To 11Ωμm 2 The damping constant α can be kept within the range of 3×10 -3 to 5×10 -3 Similarly, the saturation magnetization can be substantially maintained. However, other RA, TMR, damping constant, saturation magnetization and K ueff It is possible to be changed.

[0069] The magnetic device 100A shares the benefits of the magnetic device 100. The hybrid cap layer 140A can increase the effective magnetic anisotropy constant without substantially reducing the saturation magnetization, damping constant, resistance-area product (RA), and TMR of the magnetic junction 103A. Therefore, the magnetic device 100A can have improved performance and increased bit size scalability and high temperature operation applications.

[0070] Figure 5 An exemplary embodiment of a memory 200 is depicted, and the memory 200 may use one or more of the magnetic devices 100 and 100A, the magnetic junctions 103 / 103A and the hybrid capping layer 140 / 140A and / or other magnetic junctions. The magnetic memory 200 includes read / write column select drivers 202 and 206 and a word line select driver 204 that selects a word line 205. Note that other and / or different components may be provided. The storage area of ​​the magnetic memory 200 includes magnetic storage cells 210. A plurality of bit lines 203 are coupled to the plurality of magnetic storage cells 210. Each magnetic storage cell includes at least one magnetic device 212 and at least one selection device 214. In some embodiments, the selection device 214 is a transistor. The magnetic device 212 may be one of the magnetic device 100, the magnetic device 100A and / or other similar magnetic devices. Although one magnetic device 212 is shown for each cell 210, in other embodiments, another number of magnetic devices 212 may be provided for each cell. Because the magnetic memory 200 includes one or more of the magnetic device 100 , the magnetic device 100A, and / or similar magnetic devices, the magnetic memory 200 may share the above-described beneficial effects.

[0071] Various features have been described for the magnetic device 100 and the magnetic device 100A and the magnetic memory 200. One of ordinary skill in the art will recognize that these features can be combined in a manner not shown in the figures and not inconsistent with the devices and methods described herein. Therefore, magnetic devices according to the methods, systems and devices described herein need not be explicitly depicted.

[0072] Figure 6 An exemplary embodiment of a method 300 for making a magnetic device is depicted, which can be used in a magnetic device such as an STT-MRAM, another STT device, a SOT device, and therefore can be used in various electronic devices. For simplicity, some steps may be omitted, performed in another order, and / or combined. In addition, method 300 may begin after other steps in forming a magnetic device have been performed. Method 300 is also described in the context of forming a single magnetic device. However, multiple magnetic devices may be formed substantially simultaneously. Method 300 is also described in the context of magnetic device 100. However, another magnetic device such as magnetic device 100A may be formed.

[0073] Magnetic junction 103 is provided, via step 302. Step 302 includes depositing materials for layer 110, layer 120 and layer 130 and then defining the edges of the stack. For example, a mask may be provided over the deposited layers and ion milling of the exposed portions of the layers.

[0074] Via step 304, a hybrid cap layer 140 / 140A is also provided. Step 304 includes providing layer 142, layer 144A, and layer 146. In some embodiments, step 304 includes providing the layers in the magnetic junction stack and the hybrid cap layer. The edges of the magnetic junction 103 and the edges of the hybrid cap layer 140 can be defined after all of these layers have been deposited. For devices using magnetic devices, additional structures such as contacts and conductive lines can also be formed. Then, the fabrication of the magnetic device can be completed.

[0075] Using method 300, a magnetic device with improved performance can be fabricated. The effective magnetic anisotropy constant of the free layer 130 can be improved without substantially sacrificing the saturation magnetization, damping constant, RA, and TMR of the magnetic junction 103 / 103A. Therefore, the magnetic device 100 / 100A fabricated using method 300 can have improved performance and increased bit size scalability and high temperature operation applications.

[0076] Figure 7 An exemplary embodiment of a method 310 for making a magnetic device is depicted, which can be used in a magnetic device such as an STT-MRAM, another STT device, a SOT device, and therefore can be used in various electronic devices. For simplicity, some steps may be omitted, performed in another order, and / or combined. In addition, method 310 may begin after other steps in forming a magnetic device have been performed. Method 310 is also described in the context of forming a single magnetic device. However, multiple magnetic devices can be formed substantially simultaneously. Method 310 is also described in the context of magnetic device 100A. However, another magnetic device such as magnetic device 100 can be formed.

[0077] Via step 312, a reference layer 110A is provided. Step 312 thus includes providing a ferromagnetic layer 112 and a ferromagnetic layer 116 and a nonmagnetic layer 114. The ferromagnetic layer 116 and the ferromagnetic layer 112 may each have a perpendicular magnetic anisotropy energy that exceeds an out-of-plane demagnetization energy. Thus, the magnetic moment of the reference layer 110A may be oriented perpendicular to the plane. In other embodiments, another multi-layer or single layer may be fabricated in step 312. For example, the PEL 150 may be provided as part of step 312 as desired.

[0078] Via step 314, a non-magnetic spacer layer 120A is provided. In some embodiments, a crystalline MgO tunnel barrier layer may be formed. Step 314 may include depositing MgO using, for example, radio frequency (RF) sputtering. Metallic Mg may be deposited and then oxidized in step 314 to provide a native oxide of Mg. The MgO barrier layer / non-magnetic spacer layer 120A may also be formed in another manner. Step 314 may include annealing a portion of the formed magnetic junction to provide a crystalline MgO tunnel barrier with a (100) crystal orientation for enhanced tunnel magnetoresistance (TMR) of the magnetic junction.

[0079] Via step 316, a free layer 130 is provided. Step 316 includes depositing a material for the free layer 130. The free layer 130 provided in step 316 may desirably have a perpendicular magnetic anisotropy energy that exceeds its demagnetization energy. The magnetic moment of the free layer may thus be stably out of plane, including perpendicular to the plane. The free layer 130 provided in step 316 is also configured to switch between stable magnetic states when a write current passes through the magnetic junction 103A or through a high spin-orbit coupling line adjacent to the magnetic junction 103A. The free layer 130 provided in step 316 is magnetic, may have a high perpendicular magnetic anisotropy, and is thermally stable at operating temperatures.

[0080] Via step 318, a hybrid cap layer 140A is provided. Thus, step 318 includes providing layer 142, layer 144A, and layer 146. The fabrication of the device may then be completed. For example, the edges of the magnetic junction may be defined. This may be implemented by providing a mask over the deposited layers and ion milling the exposed portions of the layers. One or more anneals may also be performed. Note that although layers 110, 150, 120, 130, and 140A are described as being provided, in some embodiments, steps 312, 314, 316, and 318 include blanket depositing these layers. The edges of the magnetic junction 103A and the edges of the hybrid cap layer 140A may be defined after all of these layers have been deposited. For devices using magnetic junctions, additional structures such as contacts and conductive lines may also be formed. The fabrication of the magnetic device may then be completed.

[0081] Using the method 310, a magnetic device with improved performance can be fabricated. The effective magnetic anisotropy constant of the free layer 130 can be improved without substantially sacrificing the saturation magnetization, damping constant, RA, and TMR of the magnetic junction 103A / 103. Therefore, the magnetic device 100A fabricated using the method 310 can have improved performance and increased bit size scalability and high temperature operation applications.

[0082] Figure 8is a flow chart depicting an exemplary embodiment of a method 330 for providing a hybrid cap layer. For simplicity, some steps may be omitted, performed in another order, include sub-steps, and / or combined. Although described with respect to a single magnetic junction, multiple magnetic junctions may be made. For simplicity, the method is described in the context of a hybrid cap layer 140A and a magnetic device 100A. However, the method 330 may be used for any of the hybrid cap layer 140 and / or the hybrid cap layer 140A and the magnetic junction 103 and / or the magnetic junction 103A.

[0083] The insulating layer 142 is deposited via step 332. Step 332 includes depositing one or more of magnesium oxide-aluminum oxide, magnesium oxide-aluminum oxide, titanium oxide-doped magnesium oxide, and zirconium oxide-doped magnesium oxide. Other similar insulating layers that can function as oxygen barrier layers may be used in addition to or in place of the above layers.

[0084] Via step 334, a discontinuous metal layer is provided. Thus, a thin metal layer is deposited in step 334. The metal layer may include or consist of one or more of Mo, W, Nb, and Zr. In some embodiments, the metal layer is at least 0.5 angstroms thick and less than three angstroms thick. In some such embodiments, the metal layer is less than 1.5 angstroms thick. Since the layer provided is thin enough, the metal layer is discontinuous. Thus, metal islands are formed on the insulating layer 142.

[0085] Via step 336, an oxidation process is performed. The oxidation process may include one or more of a natural oxidation process, a free radical oxidation process, and a normal oxidation process. Thus, at least some of the metal islands formed in step 334 are oxidized in step 336. The formed layer may include molybdenum oxide, tungsten oxide, niobium oxide, and zirconium oxide. Thus, a discontinuous oxide layer 144A may be formed.

[0086] Via step 338, a noble metal layer is provided. Step 338 includes depositing a noble metal, for example by sputtering. The noble metal deposited in step 338 may include at least one of Ru, Pt, Ir, Rh, Pd, and Os or may consist of at least one of Ru, Pt, Ir, Rh, Pd, and Os. Step 338 may include depositing at least ten angstroms of the noble metal. In some embodiments, at least twenty angstroms are deposited. The desired effect of the noble metal layer may be achieved by a layer of twenty angstroms thick. Therefore, step 338 may include depositing a layer of no more than one hundred angstroms thick. In some embodiments, the noble metal layer provided in step 338 is no more than forty angstroms thick. In some such embodiments, the noble metal layer is no more than thirty angstroms thick.

[0087] Using method 330, a hybrid cap layer 140 and / or a hybrid cap layer 140A may be fabricated. When used in conjunction with a magnetic junction such as magnetic junction 103 and / or magnetic junction 103A, magnetic junction 130 and / or magnetic junction 103A may have improved performance. The effective magnetic anisotropy constant of free layer 130 may be improved without substantially sacrificing the saturation magnetization, damping constant, RA, and TMR of magnetic junction 103A / 103. Thus, magnetic device 100 and / or magnetic device 100A used in conjunction with hybrid cap layer 140 and / or hybrid cap layer 140A may have improved performance and increased bit size scalability and high temperature operation applications.

[0088] Methods and systems for providing magnetic devices and devices made using magnetic devices have been described. The methods and systems have been described based on the exemplary embodiments shown, and a person skilled in the art will readily recognize that there are variations of the embodiments, and any variations will be within the spirit and scope of the methods and systems. Therefore, many modifications may be made by a person skilled in the art without departing from the spirit and scope of the appended claims.

Claims

1. A magnetic device, present on a substrate and capable of being used in a magnetic device, the magnetic device comprising: Magnetic knot; as well as a hybrid cap layer, adjacent to the magnetic junction, the hybrid cap layer comprising an insulating layer, a discontinuous oxide layer and a noble metal layer, the discontinuous oxide layer being located between the insulating layer and the noble metal layer, the insulating layer being located between the magnetic junction and the noble metal layer, The noble metal layer includes at least one of Ru, Pt, Ir, Rh, Pd and Os.

2. The magnetic device of claim 1 , wherein the magnetic junction further comprises: Reference layer; A non-magnetic separator layer; as well as The free layer can be switched between multiple stable magnetic states. The nonmagnetic separation layer exists between the reference layer and the free layer. The free layer has a high perpendicular magnetic anisotropy energy and an out-of-plane demagnetization energy smaller than the perpendicular magnetic anisotropy energy. 3 . The magnetic device of claim 2 , wherein at least one of the free layer and the reference layer has a high perpendicular magnetic anisotropy energy and an out-of-plane demagnetization energy that is smaller than the perpendicular magnetic anisotropy energy. 4 . The magnetic device of claim 2 , wherein the hybrid cap layer abuts the free layer, and the free layer is located between the hybrid cap layer and the nonmagnetic spacer layer.

5. The magnetic device of claim 1, wherein the noble metal layer has a thickness of at least ten angstroms.

6. The magnetic device of claim 5, wherein the thickness is at least twenty Angstroms and no greater than one hundred Angstroms.

7. The magnetic device of claim 1, wherein the discontinuous oxide layer comprises oxide islands and metal islands.

8. The magnetic device of claim 7, wherein the metal islands comprise at least one of Mo, W, Nb, and Zr.

9. The magnetic device of claim 7, wherein the discontinuous oxide layer comprises at least one of molybdenum oxide, tungsten oxide, niobium oxide, zirconium oxide, Mg-Al oxide, Mg-Ti oxide, and Mg-Zr oxide.

10. The magnetic device of claim 1, wherein the discontinuous oxide layer has a thickness of at least 0.5 angstroms and no greater than three angstroms.

11. The magnetic device of claim 1, wherein the insulating layer comprises at least one of magnesium oxide-aluminum oxide, magnesium aluminum oxide, titanium oxide-doped magnesium oxide, and zirconium oxide-doped magnesium oxide.

12. The magnetic device of claim 2, wherein the free layer comprises at least one of FeB, FeB-X, FeCoB, FeCoB-X, Fe without B, Fe-X, FeCo, and FeCo-X, wherein X is selected from Be, Ni, Mo, Mg, Zr, Ta, V, Cr, W, Hf, Nb, and Tb.

13. A magnetic memory, present on a substrate, and comprising: A plurality of magnetic memory cells, each of the plurality of magnetic memory cells comprises a magnetic device, the magnetic device comprises at least one magnetic junction and a hybrid cap layer adjacent to the magnetic junction, the at least one magnetic junction comprises a reference layer, a nonmagnetic spacer layer and a free layer capable of switching between a plurality of stable magnetic states, the nonmagnetic spacer layer exists between the reference layer and the free layer, the free layer has a high perpendicular magnetic anisotropy energy and an out-of-plane demagnetization energy smaller than the perpendicular magnetic anisotropy energy, the hybrid cap layer comprises an insulating layer, a discontinuous oxide layer and a noble metal layer, the discontinuous oxide layer is located between the insulating layer and the noble metal layer, and the insulating layer is located between the free layer and the noble metal layer; as well as a plurality of bit lines coupled to the plurality of magnetic memory cells; The noble metal layer includes at least one of Ru, Pt, Ir, Rh, Pd and Os.

14. A method for providing a magnetic device that can be used in a magnetic device, the method comprising: Provide magnetic knot; as well as providing a hybrid cap layer adjacent to the magnetic junction, the hybrid cap layer comprising an insulating layer, a discontinuous oxide layer and a noble metal layer, the discontinuous oxide layer being located between the insulating layer and the noble metal layer, the insulating layer being located between the magnetic junction and the noble metal layer, The noble metal layer includes at least one of Ru, Pt, Ir, Rh, Pd and Os.

15. The method of claim 14, wherein the step of providing the magnetic junction further comprises: Provide a reference layer; Providing a non-magnetic separator layer; as well as A free layer is provided, the free layer being capable of switching between a plurality of stable magnetic states when a write current passes through the magnetic junction, the nonmagnetic spacer layer being present between the reference layer and the free layer, the free layer having a high perpendicular magnetic anisotropy energy and an out-of-plane demagnetization energy smaller than the perpendicular magnetic anisotropy energy.

16. The method of claim 14, wherein the step of providing the hybrid capping layer further comprises: providing the insulating layer; Providing the discontinuous oxide layer, the step of providing the discontinuous oxide layer also includes Providing a discontinuous metal layer; as well as performing an oxidation process on the discontinuous metal layer to form the discontinuous oxide layer; as well as The noble metal layer is provided on the discontinuous oxide layer. 17 . The method according to claim 16 , wherein the oxidation treatment comprises at least one of a normal oxidation treatment, a natural oxidation treatment, and a radical oxide treatment.

18. The method of claim 15, wherein the step of providing the hybrid capping layer further comprises: The hybrid cap layer is provided adjacent to the free layer, the free layer being located between the hybrid cap layer and the nonmagnetic spacer layer.

19. The method of claim 15, wherein the discontinuous oxide layer comprises at least one of molybdenum oxide, tungsten oxide, niobium oxide, zirconium oxide, Mg-Al oxide, Mg-Ti oxide, and Mg-Zr oxide, and wherein the insulating layer comprises at least one of magnesium oxide-aluminum oxide, magnesium aluminum oxide, titanium oxide-doped magnesium oxide, and zirconium oxide-doped magnesium oxide.

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