Magnetic tunnel junction device and spin-orbit moment magnetoresistive random access memory
By using thin-film structure design with materials such as Bi1-xSbx alloy and CoFeB in SOT-MRAM, the problem of spin Hall angle decrease was solved, realizing a low-power, high-density spin-orbit moment magnetoresistive random access memory.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-30
- Publication Date
- 2026-03-10
AI Technical Summary
The spin Hall angle of existing SOT-MRAM spin orbital materials decreases when they come into contact with the MTJ layer, and it is difficult to maintain a high spin Hall angle and low resistivity in semiconductor processes, resulting in high power consumption and low density of the devices.
Using Bi1-xSbx alloy as the spin orbital layer, and by inserting coupling and reinforcement layers between it and ferromagnetic layers such as CoFeB and FeB, combined with seed layer design, a special thin film structure is formed to maintain the high spin Hall angle and low resistivity characteristics of Bi1-xSbx, making it suitable for CMOS processes.
Stability of Bi1-xSbx material in CMOS process was achieved, reducing power consumption of SOT-MRAM and increasing storage density.
Smart Images
Figure CN121646276A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of memory, and in particular to a magnetic tunnel junction device and a spin-orbit torque magnetic random access memory. BACKGROUND
[0002] Spin-Orbit-Torque Magnetic Random Access Memory (SOT-MRAM) is a new type of memory, which uses the spin-orbit torque effect generated by spin current as the information writing method, adopts a three-terminal magnetic tunnel junction (MTJ) structure, separates the reading and writing paths, makes the writing speed faster, and enhances the stability of reading data. Specifically, compared with the previous generation of Spin-Transfer-Torque Magnetic Random Access Memory (STT-MRAM), the writing speed of SOT-MRAM is increased to sub-nanosecond level, and unlimited times of writing can be realized.
[0003] The essence of SOT-MRAM is still a memory chip, and its storage density is also an important technical index. Simply speaking, the smaller the storage bit area of the storage chip, the more storage bits in the same area, and the greater the storage density of the chip. In SOT-MRAM, the storage bit area is mainly determined by the write power consumption of the bit. Under the premise of meeting the necessary data retention capability, the write power consumption mainly depends on two aspects, the first is the spin Hall angle of the spin-orbit torque material, and the second is the resistivity (or conductivity) of the spin-orbit torque material. Therefore, to reduce the write power consumption of SOT-MRAM, there are several ways to reduce the geometry size, improve the spin Hall angle θ SHE of the spin-orbit torque material, and reduce the resistivity p of the spin-orbit torque material. However, since the bit geometry size is generally limited by the data retention time of the storage bit and the semiconductor processing technology, the latter two methods are more operable, that is, to select a reasonable spin-orbit torque material, compatible with the MTJ structure and the preparation process, so as to build a high-energy-efficient and high-density SOT-MRAM.
[0004] The existing spin-orbit material usually selects heavy metals such as tantalum (Ta), tungsten (W), platinum (Pt), etc. Although this kind of material has low resistivity, its spin Hall angle θ SHE is also small (less than 0.5). The prior art also discloses Topological Insulator (TI) materials such as BiSe, which have a high spin Hall angle θ SHEBi-Sb alloy (x=0.1-0.3) is a TI material, and has a high spin Hall angle (>10) and a small resistivity (about 3 times of W), as shown in Table 1: SUMMARY
[0005] Therefore, the application provides a magnetic tunnel junction device and a spin-orbit torque magnetic random access memory, which can maintain Bi 1-x Sb x The physical properties of high spin Hall angle and small resistivity in the magnetic tunnel junction film have the characteristics of low power consumption and high density.
[0006] Bi 1-x Sb x Alloy (x=0.1-0.3) is a TI material, and has a high spin Hall angle (>10) and a small resistivity (about 3 times of W), as shown in Table 1:
[0007] Table 1 Physical properties of commonly used spin-orbit materials
[0008]
[0009] However, the applicant found in research that Bi 1-x Sb x Directly and MTJ layer, especially the commonly used free layer material CoFeB, the spin Hall angle will decrease significantly, and there is no advantage compared with W. At the same time, the performance of TI type material is greatly related to the substrate, and only a suitable substrate can induce a crystal structure with a large spin Hall angle in Bi 1-x Sb x On the silicon substrate commonly used in semiconductor process, the spin Hall angle of Bi 1-x Sb x will decrease significantly (from 10 to less than 3). Therefore, whether it can adapt to CMOS related process and material, and maintain the stable performance of Bi 1-x Sb x is the main problem of the application. Based on this, the application provides a new magnetic tunnel junction film stacking design, which introduces a seed layer and other ways to introduce Bi 1-x Sb x in MTJ and maintains its physical properties, and further prepares a low-power and high-density SOT-MRAM device.
[0010] The application provides a magnetic tunnel junction device, which comprises: a barrier layer, a second ferromagnetic layer, a coupling layer, a first ferromagnetic layer and a spin-orbit layer which are sequentially stacked.
[0011] The material of the spin-orbit layer is Bi1-x Sb x 0.1≤x≤0.3;
[0012] the first ferromagnetic layer is selected from a Co layer, a CoX alloy layer, a CoX alloy doped material layer, or a Co-containing multilayer film, wherein X is selected from Pt, Ni, Fe, or Pd;
[0013] the material of the second ferromagnetic layer is selected from CoFeB, FeB, a CoFeB-containing multilayer film, or a FeB-containing multilayer film.
[0014] In some specific implementations, the magnetic tunnel junction device further comprises a seed layer disposed on a side of the spin orbit layer away from the barrier layer.
[0015] In some specific implementations, the seed layer has a material with a lattice constant that is within 5% of a lattice constant of Bi1-xSbx.
[0016] In some specific implementations, the seed layer has a material selected from FeN, TiN, NbN, ZnO, or MgO.
[0017] In some specific implementations, the seed layer has a thickness of 1 nm.
[0018] In some specific implementations, the magnetic tunnel junction device further comprises an enhancement layer disposed between the first ferromagnetic layer and the spin orbit layer.
[0019] In some specific implementations, the enhancement layer has a material selected from Pt or a metal oxide.
[0020] In some specific implementations, the metal oxide is selected from NiO, TaO, CrO, or CuO.
[0021] In some specific implementations, the enhancement layer has a thickness of 0.3 nm to 0.6 nm.
[0022] In some specific implementations, the magnetic tunnel junction device further comprises a substrate disposed on a side of the seed layer away from the barrier layer, and a reference layer, an anti-ferromagnetic coupling layer, a pinning layer, and a capping layer disposed in sequence on a side of the barrier layer away from the seed layer.
[0023] In some specific implementations, the magnetic tunnel junction device further comprises a reference layer, an anti-ferromagnetic coupling layer, a pinning layer, a capping layer, and a substrate disposed on a side of the barrier layer away from the seed layer.
[0024] In some specific implementations, the CoFeB-containing multilayer film comprises a CoFeB film, an interposed layer, and a CoFeB film disposed in sequence.
[0025] The material of the insertion layer is selected from Ta, Mo, Ir, W, Pt or Mg.
[0026] In some specific implementations, the thickness of the insertion layer is 0.1 nm to 0.5 nm.
[0027] In some specific implementations, the thickness of the coupling layer is 0.2 nm to 0.5 nm.
[0028] This application also provides a spin-orbit moment magnetoresistive random access memory, including the magnetic tunnel junction device described in the above technical solution.
[0029] This application uses Bi 1-x Sb x As the material for the spin-orbit layer, a barrier layer, a second ferromagnetic layer, a coupling layer, a first ferromagnetic layer, and a spin-orbit layer are sequentially stacked. The material of the spin-orbit layer is Bi. 1-x Sb x 0.1≤x≤0.3; the first ferromagnetic layer is selected from a Co layer, a CoX alloy layer, a CoX alloy doped material layer, or a Co-containing multilayer film, wherein X is selected from Pt, Ni, Fe, or Pd; the material of the second ferromagnetic layer is selected from CoFeB, FeB, a CoFeB-containing multilayer film, or a FeB-containing multilayer film. This application is based on Bi... 1- x Sb x A coupling layer and a first ferromagnetic layer selected from Co layers, CoX alloy layers, CoX alloy doped material layers, or Co-containing multilayer films are inserted between the spin orbital layer and the second ferromagnetic layer composed of CoFeB, FeB, CoFeB-containing multilayer films, or FeB-containing multilayer films. Through thin film structure design, the resulting magnetic tunnel junction device can maintain Bi 1-x Sb x By leveraging the physical properties of the SOT-MRAM, namely maintaining a high spin Hall angle (>10) and a low resistivity (only about three times that of W), it is hoped that low-power, high-density SOT-MRAM devices can be fabricated. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of the magnetic tunnel junction provided in the first embodiment of this application;
[0031] Figure 2 This is a schematic diagram of the magnetic tunnel junction provided in the second embodiment of this application;
[0032] Figure 3 This is a schematic diagram of the magnetic tunnel junction provided in the third embodiment of this application;
[0033] Figure 4 This is a schematic diagram of the magnetic tunnel junction provided in the fourth embodiment of this application;
[0034] Figure 5 This is a schematic diagram of the magnetic tunnel junction provided in the fifth embodiment of this application;
[0035] Figure 6 This is a schematic diagram of the magnetic tunnel junction provided in the sixth embodiment of this application;
[0036] Figure 7 This is a schematic diagram of the magnetic tunnel junction provided in the seventh embodiment of this application. Detailed Implementation
[0037] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.
[0038] The terms “including,” “having,” or “containing,” including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.
[0039] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.
[0040] The use of any and all instances or exemplary language such as “e.g.” or “including” in this document is merely intended to better illustrate the invention and is not intended to limit the scope of the invention unless the claims are made. No language in this specification should be construed as indicating that any unclaimed element is essential to the practice of the invention.
[0041] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately." Here, "approximately" generally means an actual value within plus or minus 10%, 5%, 1%, or 0.5% of a particular value or range.
[0042] This application provides a magnetic tunnel junction device, comprising: a barrier layer, a second ferromagnetic layer, a coupling layer, a first ferromagnetic layer, and a spin-orbit layer stacked sequentially;
[0043] The material of the spin orbital layer is Bi. 1-xSb x , 0.1≤x≤0.3;
[0044] The first ferromagnetic layer is selected from a Co layer, a CoX alloy layer, a CoX alloy doped material layer, or a Co-containing multilayer film, wherein X is selected from Pt, Ni, Fe, or Pd;
[0045] The material of the second ferromagnetic layer is selected from CoFeB, FeB, CoFeB-containing multilayer film, or FeB-containing multilayer film.
[0046] See Figure 1 , Figure 1 This is a schematic diagram of the structure of the magnetic tunnel junction provided in the first embodiment of this application. The magnetic tunnel junction 100 includes a barrier layer 102, a free layer 200 and a spin orbital layer 300 arranged sequentially. The free layer 200 includes a second ferromagnetic layer 201, a coupling layer 202 and a first ferromagnetic layer 203.
[0047] This application uses Bi 1-x Sb x (0.1≤x≤0.3) is the material of the spin orbital layer 300. It is a topological insulator (TI) material. When it is not in contact with the second ferromagnetic layer 201, it can maintain its high spin Hall angle (>10) and low resistivity (about three times that of W), thus enabling the fabrication of low-power, high-density SOT-MRAM devices.
[0048] In the magnetic tunnel junction provided in this application, the free layer 200 includes a second ferromagnetic layer 201, a coupling layer 202, and a first ferromagnetic layer 203 stacked sequentially. The first ferromagnetic layer 203 is close to the spin-orbit layer 300, and the second ferromagnetic layer 203 is adjacent to the barrier layer 102 of the tunneling layer. In some specific implementations, the first ferromagnetic layer has bulk perpendicular magnetic anisotropy, and its material can be selected from a Co layer, a CoX alloy layer, a CoX alloy doped material layer, or a Co-containing multilayer film. When the material of the first ferromagnetic layer is a CoX alloy, X is selected from Pt, Ni, Fe, or Pd; when the material of the first ferromagnetic layer is a CoX alloy doped material, X is selected from Pt, Ni, Fe, or Pd, and the doping material is selected from Pt, Cr, V, Pd, Ni, or Tb; when the first ferromagnetic layer is a Co-containing multilayer film, it can be a multilayer Co alloy film, and this application does not impose any special restrictions on it. In some specific implementations, the thickness of the first ferromagnetic layer 203 is less than 1 nm.
[0049] The material of the second ferromagnetic layer 201 is selected from CoFeB, FeB, or a CoFeB-containing multilayer film, and it is ferromagnetically coupled to the second ferromagnetic layer 201 through the coupling layer 202. In some specific implementations, when the second ferromagnetic layer 201 is a CoFeB-containing multilayer film, it includes a CoFeB film, an insertion layer, and a CoFeB film stacked sequentially, wherein the material of the insertion layer is selected from Ta, Mo, Ir, W, Pt, or Mg. In some specific implementations, the thickness of the insertion layer is less than 0.5 nm, preferably 0.1 nm to 0.5 nm.
[0050] In some specific implementations, the material of the coupling layer 202 is selected from MgO, Mo, W, Ta, or Ir. In some specific implementations, the thickness of the coupling layer 202 is 0.2 nm to 0.5 nm.
[0051] The free layer 200 is adjacent to the barrier layer 102. This application does not impose any special restrictions on the material and thickness of the barrier layer 102; any technical parameters known to those skilled in the art are acceptable.
[0052] This application is in Bi 1-x Sb x A coupling layer and a first ferromagnetic layer selected from Co layers, CoX alloy layers, CoX alloy doped material layers, or Co-containing multilayer films are inserted between the spin orbital layer and the second ferromagnetic layer composed of CoFeB, FeB, CoFeB-containing multilayer films, or FeB-containing multilayer films. Through thin film structure design, the resulting magnetic tunnel junction device can maintain Bi 1-x Sb x By leveraging the physical properties of the SOT-MRAM, namely maintaining a high spin Hall angle (>10) and a low resistivity (approximately three times that of W), it is hoped that low-power, high-density SOT-MRAM devices can be fabricated.
[0053] In order to induce Bi 1-x Sb x To achieve a higher spin Hall angle, in the second embodiment of this application, a seed layer 301 is provided in the direction of the spin orbital layer 300 away from the barrier layer 102. This seed layer 301 can induce Bi 1-x Sb x Crystal structures with higher spin Hall angles. See also Figure 2 , Figure 2 This is a schematic diagram of the structure of the magnetic tunnel junction provided in the second embodiment of this application. The magnetic tunnel junction 500 includes a barrier layer 102, a free layer 200, a spin orbital layer 300 and a seed layer 301 arranged sequentially. The free layer 200 includes a second ferromagnetic layer 201, a coupling layer 202 and a first ferromagnetic layer 203.
[0054] In this application, a seed layer 301 is provided on the side of the spin orbital layer 300 away from the barrier layer 102. The seed layer 301 can induce Bi 1-x Sb x The material forms a crystal structure with a large spin Hall angle. In some specific implementations, the seed layer 301 is made of a material similar to Bi. 1-x Sb x Materials with a lattice constant difference ≤ 5%, including but not limited to FeN, TiN, NbN, ZnO, or MgO. For example, Bi 0.85 Sb 0.15 The lattice constant is The lattice constants of FeN, TiN, and NbN are respectively The lattice constant of ZnO is The lattice constant of MgO is All of these can serve as seed layers. In some specific implementations, the thickness of the seed layer is 1 nm. The other layers are similar to those in the above embodiments, and will not be described in detail here.
[0055] In order to induce Bi 1-x Sb x To achieve a higher spin Hall angle, in a third embodiment of this application, a reinforcement layer 302 is provided between the first ferromagnetic layer 203 and the spin orbital layer 300. This reinforcement layer 302 can enhance the SOT effect. See also Figure 3 , Figure 3 This is a schematic diagram of the structure of a magnetic tunnel junction provided in the third embodiment of this application. The magnetic tunnel junction 600 includes a barrier layer 102, a free layer 200, a reinforcement layer 302, a spin orbital layer 300 and a seed layer 301 arranged sequentially. The free layer 200 includes a second ferromagnetic layer 201, a coupling layer 202 and a first ferromagnetic layer 203.
[0056] In some specific implementations, the material of the reinforcing layer 302 is selected from Pt or metal oxides, wherein the metal oxide is selected from NiO, TaO, CrO, or CuO. In some specific implementations, the thickness of the reinforcing layer is 0.3 nm to 0.6 nm. The other layers are similar to those in the above embodiments, and will not be described in detail here.
[0057] The magnetic tunnel junction device provided in this application can be a top-pinned thin-film structure, see [link to relevant documentation]. Figure 4 , Figure 4 This is a schematic diagram of the structure of the magnetic tunnel junction provided in the fourth embodiment of this application. The magnetic tunnel junction 700 includes other layers 101, a barrier layer 102, a free layer 200, a spin orbital layer 300, a seed layer 301 and a substrate 400 arranged sequentially. The free layer 200 includes a second ferromagnetic layer 201, a coupling layer 202 and a first ferromagnetic layer 203.
[0058] In some specific implementations, the other layers 101 include a reference layer, an antiferromagnetic coupling layer, a pinning layer, and a capping layer (not shown in the figure) sequentially disposed on the side of the barrier layer 102 away from the seed layer 301. This application does not impose any special limitations on the materials and thicknesses of the above layers; parameters well-known to those skilled in the art are acceptable. The substrate 400 can be a silicon substrate, and this application does not impose any special limitations on it. The other layers are similar to those in the above embodiments, and will not be described in detail here.
[0059] In some specific implementations, the magnetic tunnel junction 700 may further include a reinforcing layer 302 disposed between the spin orbital layer 300 and the first ferromagnetic layer 203, such as... Figure 5 As shown, Figure 5 This is a schematic diagram of the magnetic tunnel junction provided in the fifth embodiment of this application. The material and thickness of the reinforcing layer 302 are as described above, and will not be repeated here.
[0060] The magnetic tunnel junction device provided in this application can be a bottom-pinned thin-film structure, see [link to relevant documentation]. Figure 6 , Figure 6 This is a schematic diagram of the structure of the magnetic tunnel junction provided in the sixth embodiment of this application. The magnetic tunnel junction 800 includes a seed layer 301, a spin orbital layer 300, a free layer 200, a barrier layer 102, other layers 101 and a substrate 400 arranged sequentially. The free layer 200 includes a second ferromagnetic layer 201, a coupling layer 202 and a first ferromagnetic layer 203.
[0061] In some specific implementations, the other layers 101 include a reference layer, an antiferromagnetic coupling layer, a pinning layer, a capping layer, and a substrate (not shown in the figure) sequentially disposed on the side of the barrier layer 102 away from the seed layer 301. This application does not impose any special limitations on the materials and thicknesses of the above layers; parameters well-known to those skilled in the art are acceptable. The substrate 400 can be a silicon substrate, and this application does not impose any special limitations on it. The other layers are similar to those in the above embodiments, and will not be described in detail here.
[0062] In some specific implementations, the magnetic tunnel junction 800 may further include a reinforcing layer 302 disposed between the spin orbital layer 300 and the first ferromagnetic layer 203, such as... Figure 7 As shown, Figure 7 This is a schematic diagram of the magnetic tunnel junction provided in the seventh embodiment of this application. The material and thickness of the reinforcing layer 302 are as described above and will not be repeated here.
[0063] This application does not impose any special restrictions on the fabrication method of the magnetic tunnel junction device. In order to simplify the process, each layer structure can be fabricated by magnetron sputtering. After each layer structure is formed in sequence, annealing is performed to form a topological insulator crystal structure of the spin orbital layer. Alternatively, one layer structure can be formed and annealed before other structures are formed. This application does not impose any special restrictions on this.
[0064] This application also provides a spin-orbit-moment magnetoresistive random access memory (SORM), including the magnetic tunnel junction device described in the above technical solution. This application does not impose any special limitations on other structures of the SORM; structures, materials, and parameters well-known to those skilled in the art are acceptable.
[0065] This application uses Bi 1-x Sb x As the material for the spin orbital layer, a barrier layer, a second ferromagnetic layer, a coupling layer, a first ferromagnetic layer, a spin orbital layer, and a seed layer are sequentially stacked. Through thin film structure design and the introduction of the seed layer, the resulting magnetic tunnel junction device can maintain Bi 1-x Sb x By leveraging the physical properties of the SOT-MRAM, namely maintaining a high spin Hall angle (>10) and a low resistivity (approximately three times that of W), it is hoped that low-power, high-density SOT-MRAM devices can be fabricated.
[0066] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A magnetic tunnel junction device, comprising: The barrier layer, the second ferromagnetic layer, the coupling layer, the first ferromagnetic layer and the spin-orbit layer are sequentially stacked; The material of the spin-orbit layer is Bi 1-x Sb x 0.1≤x≤0.3 The first ferromagnetic layer is selected from a Co layer, a CoX alloy layer, a CoX alloy doped material layer or a Co-containing multilayer film, wherein X is selected from Pt, Ni, Fe or Pd; The material of the second ferromagnetic layer is selected from CoFeB, FeB, a CoFeB-containing multilayer film or a FeB-containing multilayer film.
2. The magnetic tunnel junction device of claim 1, wherein, A seed layer is further arranged on the side of the spin-orbit layer away from the barrier layer.
3. The magnetic tunnel junction device of claim 2, wherein, The lattice constant of the material of the seed layer is ≤5% different from the lattice constant of Bi1-xSbx.
4. The magnetic tunnel junction device of claim 3, wherein, The material of the seed layer is selected from FeN, TiN, NbN, ZnO or MgO.
5. The magnetic tunnel junction device of claim 4, wherein, The thickness of the seed layer is 1 nm.
6. The magnetic tunnel junction device of any of claims 2-5, wherein, An enhancement layer is further arranged between the first ferromagnetic layer and the spin-orbit layer.
7. The magnetic tunnel junction device of claim 6, wherein, The material of the enhancement layer is selected from Pt or a metal oxide.
8. The magnetic tunnel junction device of claim 4, wherein, The metal oxide is selected from NiO, TaO, CrO or CuO.
9. The magnetic tunnel junction device of claim 5, wherein, The thickness of the enhancement layer is 0.3 nm to 0.6 nm.
10. The magnetic tunnel junction device of any one of claims 2-5, wherein, A substrate is further arranged on the side of the seed layer away from the barrier layer, and a reference layer, an anti-ferromagnetic coupling layer, a pinning layer and a capping layer are sequentially arranged on the side of the barrier layer away from the seed layer.
11. The magnetic tunnel junction device of claim 10, wherein, A reference layer, an anti-ferromagnetic coupling layer, a pinning layer, a capping layer and a substrate are further arranged on the side of the barrier layer away from the seed layer.
12. The magnetic tunnel junction device of claim 11, wherein, The CoFeB-containing multilayer film comprises a CoFeB film, an interposed layer and a CoFeB film which are sequentially stacked; The material of the interposed layer is selected from Ta, Mo, Ir, W, Pt or Mg.
13. The magnetic tunnel junction device of claim 12, wherein, The thickness of the interposed layer is 0.1 nm to 0.5 nm.
14. The magnetic tunnel junction device of claim 13, wherein, The thickness of the coupling layer is 0.2 nm to 0.5 nm.
15. A spin-orbit torque random access memory comprising the magnetic tunnel junction device of any one of claims 1 to 14.