KR20220069798A - Magnetic tunneling junctions based on spin-orbit torque and method manufacturing thereof - Google Patents

Abstract

According to the present invention, disclosed are a magnetic tunnel junction based on spin-orbit torque (SOT) and a manufacturing method thereof. The present invention comprises: a spin-torque active layer formed on a substrate; a free layer formed on the spin-torque active layer; a tunnel barrier layer formed on the free layer; and a fixing layer formed on the tunnel barrier layer. The spin-torque active layer includes a W-X alloy, wherein W is tungsten and X includes at least one of a group 4 semiconductor and a group 3-5 semiconductor.

Description

Spin-orbit torque (SOT)-based magnetic tunnel junction and manufacturing method thereof

The present invention relates to a spin-orbit torque (SOT)-based magnetic tunnel junction and a method for manufacturing the same, and more particularly, to a W-X alloy having a large spin-orbit coupling (where W is tungsten and , wherein X includes at least one of a group 4 semiconductor and a group 3-5 semiconductor) thin film is used as a spin torque active layer to enable spin-orbit torque switching and high spin-orbit torque efficiency at low resistivity To a spin-orbit torque (SOT)-based magnetic tunnel junction and a method for manufacturing the same.

The magnetic tunnel junction basically has a triple layer structure of ferromagnetic material/oxide/ferromagnetic material, and includes a magnetization free layer (FL), a tunnel barrier (TB), and a magnetization pinned layer (PL), respectively. , the positions of the free layer and the fixed layer can be interchanged. It uses the property that the value of the tunneling current passing through the tunnel barrier changes according to the state in which the spin directions of the adjacent free layer and the pinned layer are arranged in parallel or antiparallel with the tunnel barrier interposed therebetween. The resistance difference is called the tunnel magnetoresistance ratio (TMR). The spin direction of the pinned layer is fixed, and information can be input by manipulating the spin direction of the free layer by flowing a magnetic field or current.

A magnetic tunnel junction (MTJ), a core element of a spin-orbit torque (SOT) switching-based magnetic random access memory (MRAM), is a non-magnetic spin torque active layer/first magnetic layer (magnetization free layer, hereinafter referred to as a magnetic tunnel junction). It is composed of free layer)/tunnel barrier layer/second magnetic layer (magnetization pinned layer, hereinafter referred to as pinned layer), and tunnel magnetoresistance ( Reading information using the phenomenon of tunneling magnetoresistance (TMR).

In order to realize a high tunnel magnetoresistance ratio, high write stability, low write current, and high integration, a magnetic tunnel junction must have a characteristic perpendicular magnetic anisotropy (PMA). The perpendicular magnetic anisotropy means that the magnetization direction of the magnetic layer is perpendicular to the surface of the magnetic layer.

Recently, spin orbital torque that induces switching of the free layer using the spin Hall effect or Rashba effect, which occurs when current flows in the in-plane parallel direction of the spin torque active layer adjacent to the free layer (Spin-orbit torque, SOT) phenomenon was discovered, and it is attracting attention as a technology capable of recording information at higher speed and lower current consumption than the existing spin-transfer torque (STT) writing method.

Therefore, research on using a material having a large spin Hall angle (SHA), which is a physical quantity indicating low specific resistance and high spin orbit torque efficiency, as the spin torque active layer is required.

Korean Patent Laid-Open Patent No. 10-2020-0030277, "Semiconductor device having spin-orbit torque line and operating method therefor" Korean Patent Laid-Open Patent No. 10-2020-0066848, "Semiconductor device having spin-orbit torque line"

An embodiment of the present invention uses a thin film of a W-X alloy (where W is tungsten, wherein X includes at least one of a group 4 semiconductor and a group 3-5 semiconductor) having high spin-orbit coupling. An object of the present invention is to provide a spin-orbit torque-based magnetic tunnel junction capable of switching spin-orbit torque by using it as an active layer and exhibiting high spin-orbit torque efficiency at low resistivity and a method for manufacturing the same.

An embodiment of the present invention is to provide a spin orbit torque-based magnetic tunnel junction capable of controlling the switching current by adjusting the X composition of the W-X alloy and a method for manufacturing the same.

An embodiment of the present invention uses a tungsten-silicon alloy as a spin torque active layer to maintain a perpendicular magnetic anisotropy (PMA) in various heat treatment temperature ranges. A spin orbit torque-based magnetic tunnel junction and a manufacturing method thereof are provided. want to

A spin-orbit torque (SOT)-based magnetic tunnel junction according to an embodiment of the present invention includes a spin-orbit active layer formed on a substrate; a free layer formed on the spin torque active layer; a tunnel barrier layer formed on the free layer; and a pinned layer formed on the tunnel barrier layer. and, the spin torque active layer includes a W-X alloy (wherein W is tungsten, and X includes at least one of a group 4 semiconductor and a group 3-5 semiconductor).

The spin torque active layer may be an electrode providing an in-plane current in contact with the free layer.

As the composition content of X included in the W-X alloy increases, the switching current may be reduced.

The composition content of silicon included in the tungsten-silicon alloy may be 0.1 at% to 10.6 at%.

In the spin orbit torque-based magnetic tunnel junction, a switching current may be reduced as the heat treatment temperature at which the perpendicular magnetic anisotropy is expressed increases.

The heat treatment temperature at which the perpendicular magnetic anisotropy is expressed may be 300 °C to 500 °C.

The composition content of X included in the W-X alloy may be adjusted according to the heat treatment temperature at which the perpendicular magnetic anisotropy is expressed.

The spin torque active layer, the free layer, the tunnel barrier layer, and the pinned layer may have a cross shape in plan view.

The spin torque active layer may have a cross shape in plan view, and the free layer, the tunnel barrier layer, and the pinned layer may be disposed in an island shape at the center of the cross shape spin torque active layer.

The substrate may include a native oxide layer on a surface in contact with the spin torque active layer.

The spin torque active layer may further include a buffer layer at a lower portion.

The spin orbit torque-based magnetic tunnel junction may further include a capping layer on the pinned layer.

A method of manufacturing a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention includes: forming a spin torque active layer on a substrate; forming a free layer on the spin torque active layer; forming a tunnel barrier layer on the free layer; forming a pinned layer formed on the tunnel barrier layer; and performing a heat treatment to develop perpendicular magnetic anisotropy to the free layer and the pinned layer, wherein the forming of the spin torque active layer on the substrate includes sputtering a W target and an X target in a vacuum chamber at the same time. A W-X alloy thin film (wherein W is tungsten and X includes at least one of a group 4 semiconductor and a group 3-5 semiconductor) is formed on the substrate disposed in the vacuum chamber.

The composition of the tungsten-silicon alloy thin film may be adjusted according to the power of the tungsten target and the silicon target.

The composition content of X included in the W-X alloy may be 0.1at% to 10.6at%.

As the heat treatment temperature increases, the switching current may decrease.

The heat treatment temperature may be 300 °C to 500 °C.

The composition content of X included in the W-X alloy may be adjusted according to the heat treatment temperature.

The forming of the spin torque active layer on the substrate may further include patterning the tungsten-silicon alloy thin film in a cross shape.

According to an embodiment of the present invention, spin-orbit torque switching is possible by using a W-X alloy thin film with high spin-orbit coupling as a spin torque active layer, and high spin orbit torque ( It is possible to provide a spin-orbit torque-based magnetic tunnel junction exhibiting spin-orbit torque) efficiency and a method for manufacturing the same.

According to an embodiment of the present invention, it is possible to provide a spin orbit torque-based magnetic tunnel junction capable of controlling the switching current by adjusting the X composition of the W-X alloy and a method for manufacturing the same.

According to an embodiment of the present invention, using a tungsten-silicon alloy as a spin torque active layer, perpendicular magnetic anisotropy (PMA) can be maintained in various heat treatment temperature ranges, a spin orbit torque-based magnetic tunnel junction and a method for manufacturing the same can provide

1 is a cross-sectional view illustrating a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention.
2 is a plan view illustrating a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention.
3 is a flowchart illustrating a method of manufacturing a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention.
4 is a cross-sectional view illustrating a structure for measuring spin orbit torque efficiency of a spin orbit torque based magnetic tunnel junction according to an embodiment of the present invention.
5 is a spin orbit torque-based magnetic tunnel junction according to the embodiment of the present invention shown in FIG. 4 in which heat treatment was performed at 300° C. for 1 hour (hereinafter, W-Si/CoFeB/MgO/Ta structure according to Example 1) It is a graph showing the magnetic hysteresis curve according to the silicon content (0at% to 10.6 at%) of the spin torque active layer when a magnetic field is applied to the thin film in the out-of-plane direction. , FIG. 6 is a graph showing a magnetic hysteresis curve according to the silicon content (0at% to 10.6 at%) of the spin torque active layer when a magnetic field is applied in the in-plane direction of the thin film.
7 shows the silicon content (0at) of the spin torque active layer when a magnetic field is applied in the direction perpendicular to the plane of the thin film to the W-Si/CoFeB/MgO/Ta structure according to Example 1-1, which was heat treated at 400° C. for 1 hour. % to 10.6 at%) is a graph showing the hysteresis curve, and FIG. 8 is a hysteresis curve according to the silicon content (0at% to 10.6 at%) of the spin torque active layer when a magnetic field is applied in the in-plane direction of the thin film. is a graph showing
9 shows the silicon content (0at) of the spin torque active layer when a magnetic field is applied to the W-Si/CoFeB/MgO/Ta structure according to Example 1-1, which was heat treated at 500° C. for 1 hour in the direction perpendicular to the plane of the thin film. % to 10.6 at%) is a graph showing the hysteresis curve, and FIG. 10 is a hysteresis curve according to the silicon content (0 at% to 10.6 at%) of the spin torque active layer when a magnetic field is applied in the in-plane direction of the thin film. is a graph showing
11A is a schematic diagram showing a W-Si/CoFeB/MgO/Ta structure according to Example 1-2 having perpendicular magnetic anisotropy, and FIG. 11B is a vacuum heat treatment at 300° C. and 500° C. for 1 hour, FIG. Spin trajectory of the device measured using a harmonics measurement method in the composition range of the tungsten-silicon alloy layer in the W-Si/CoFeB/MgO/Ta structure according to Example 1-2 having the perpendicular magnetic anisotropy shown in 11a It is a graph showing the efficiency of torque.
12 is a tungsten-silicon alloy in the W-Si/CoFeB/MgO/Ta structure according to Example 1-2 having the perpendicular magnetic anisotropy shown in FIG. 11a by performing vacuum heat treatment at 300° C. and 500° C. for 1 hour. It is a graph showing the electrical resistivity value of the alloy measured using a four-point probe in the composition range of the layer.
13 shows when an external magnetic field of +100 Oe is applied to the W-Si/CoFeB/MgO/Ta structure according to Example 1-1 having perpendicular magnetic anisotropy by vacuum heat treatment at 300° C. for 1 hour, tungsten- It is a graph showing switching characteristics according to the composition (unit: at%) of the silicon alloy layer, and FIG. 14 is a tungsten-switching according to the composition (unit: at%) of the silicon alloy layer when an external magnetic field of -100 Oe is applied. It is a graph showing characteristics.
15 shows that when an external magnetic field of +100 Oe is applied to the W-Si/CoFeB/MgO/Ta structure according to Example 1-1 having perpendicular magnetic anisotropy by vacuum heat treatment at 500° C. for 1 hour, tungsten- It is a graph showing the switching characteristics according to the composition (unit: at%) of the silicon alloy layer, Figure 16 is when an external magnetic field of -100 Oe is applied, tungsten-switching according to the composition (unit: at%) of the silicon alloy layer It is a graph showing characteristics.
17a is a schematic diagram showing a W-Si/CoFeB/MgO/Ta structure according to Example 1-1 having perpendicular magnetic anisotropy, and FIG. 17b is a vacuum heat treatment at 300° C. and 500° C. for 1 hour, vertical When an external magnetic field of ±100 Oe is applied to the W-Si/CoFeB/MgO/Ta structure according to Example 1-1 having magnetic anisotropy, the switching current density change according to the composition of the tungsten-silicon alloy layer, which is the spin torque active layer, It is the graph shown.
18 is a view showing the change of an external magnetic field after heat treatment of the W-Si/CoFeB/MgO/Ta structure according to Examples 1-3 including a spin torque active layer having a silicon content of 0 at% at 300° C. for 1 hour; FIG. It is a graph measuring the switching current (current density), and FIG. 19 is a W-Si/CoFeB/MgO/Ta structure according to Example 1-3 including a spin torque active layer having a silicon content of 7.4 at% 1 at 300°C. After heat treatment for a period of time, it is a graph measuring the switching current (current density) according to the change in the external magnetic field, and FIG. 20 is W-Si according to Examples 1-3 including a spin torque active layer having a silicon content of 9.1 at%. This is a graph measuring the switching current (current density) according to the change in the external magnetic field after the /CoFeB/MgO/Ta structure was heat treated at 300° C. for 1 hour.
21 is a view showing the change of an external magnetic field after heat treatment of a W-Si/CoFeB/MgO/Ta structure according to Examples 1-3 including a spin torque active layer having a silicon content of 0 at% at 500° C. for 1 hour; It is a graph measuring the switching current (current density), and FIG. 22 is a W-Si/CoFeB/MgO/Ta structure according to Example 1-3 including a spin torque active layer having a silicon content of 7.4 at% at 500°C. After heat treatment for a period of time, it is a graph measuring the switching current (current density) according to the change in the external magnetic field, and FIG. 23 is W-Si according to Examples 1-3 including a spin torque active layer having a silicon content of 9.1 at%. This is a graph measuring the switching current (current density) according to the change in the external magnetic field after the /CoFeB/MgO/Ta structure was heat treated at 500° C. for 1 hour.
24 is a W-Si/CoFeB/MgO/Ta structure according to Example 2, in which the silicon composition of the tungsten-silicon alloy layer is 3.0 at%, after vacuum heat treatment at 500° C. for 1 hour, leader pod backscattering ( It is a graph showing the Si content in W using Rutherford Backscattering, 25 shows a W-Si/CoFeB/MgO/Ta structure according to Example 2, in which the silicon composition of the tungsten-silicon alloy layer is 4.0 at%, after vacuum heat treatment at 500° C. for 1 hour, followed by leader pod backscattering ( It is a graph showing the Si content in W using Rutherford Backscattering), and FIG. 26 is a W-Si/CoFeB/MgO/Ta structure according to Example 2 in which the silicon composition of the tungsten-silicon alloy layer is 7.4 at% at 500°C. After vacuum heat treatment for 1 hour, it is a graph showing the Si content in W using Rutherford Backscattering, and FIG. 27 is a tungsten-silicon alloy layer in Example 2 in which the silicon composition is 9.1 at%. After vacuum annealing the W-Si/CoFeB/MgO/Ta structure at 500° C. for 1 hour, it is a graph showing the Si content in W using Rutherford Backscattering.
28 is a schematic diagram showing a CoFeB/W-Si/CoFeB/MgO/Ta structure according to Example 3 having perpendicular magnetic anisotropy, and FIG. 29 is a vacuum heat treatment at 500° C. for 1 hour, in Example 3 A graph showing a hysteresis curve when a magnetic field is applied to the CoFeB/W-Si/CoFeB/MgO/Ta structure according to the out-of-plane and in-plane directions of the thin film 30 to 32 are graphs showing hysteresis curves measuring magnetization reversal of no magnetic field applied with current.
33 shows the silicon composition (0.0, 4.0) of the tungsten-silicon alloy layer of the W-Si/CoFeB/MgO/Ta structure according to Example 1-1 having perpendicular magnetic anisotropy by vacuum heat treatment at 500° C. for 1 hour. , 9.1 at%) is a graph showing the results of X-ray diffraction (XRD).
34 is a tungsten-silicon alloy layer of silicon composition (0.0, 4.0, 9.1 at%) is an image showing the phase of the thin film using an in-plane transmission electron microscope (TEM), and FIG. 35 is a vacuum heat treatment at 500° C. for 1 hour. , In-plane transmission of the thin film according to the silicon composition (0.0, 4.0, 9.1 at%) of the tungsten-silicon alloy layer of the W-Si/CoFeB/MgO/Ta structure according to Example 2 having perpendicular magnetic anisotropy It is an image showing the image of the thin film using an electron microscope (Transmission Electron Microscope, TEM).

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and contents described in the accompanying drawings, but the present invention is not limited or limited by the embodiments.

The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, "comprises" and/or "comprising" does not exclude the presence or addition of one or more other elements, steps, or elements mentioned.

As used herein, “embodiment”, “example”, “aspect”, “exemplary”, etc. are to be construed as advantageous in any aspect or design described as being preferred or advantageous over other aspects or designs. is not doing

Also, the term 'or' means 'inclusive or' rather than 'exclusive or'. That is, unless stated otherwise or clear from context, the expression 'x employs a or b' means any of natural inclusive permutations.

Also, as used herein and in the claims, the singular expression "a" or "an" generally means "one or more," unless stated otherwise or clear from the context that it relates to the singular form. should be interpreted as

The terms used in the description below have been selected as general and universal in the related technical field, but there may be other terms depending on the development and/or change of technology, customs, preferences of technicians, and the like. Therefore, the terms used in the description below should not be construed as limiting the technical idea, but as illustrative terms for describing the embodiments.

In addition, in a specific case, there is a term arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the corresponding description. Therefore, the terms used in the description below should be understood based on the meaning of the term and the content throughout the specification, rather than the simple name of the term.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly defined in particular.

Meanwhile, in the description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the terms used in this specification are terms used to properly express the embodiment of the present invention, which may vary according to the intention of a user or operator or customs in the field to which the present invention belongs. Accordingly, definitions of these terms should be made based on the content throughout this specification.

1 is a cross-sectional view illustrating a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention.

A spin-orbit torque (SOT)-based magnetic tunnel junction according to an embodiment of the present invention includes a spin-orbit active layer 120 and a spin torque active layer 120 formed on a substrate 110 . A free layer 130 formed thereon, a tunnel barrier layer 140 formed on the free layer 130 , and a pinned layer 150 formed on the tunnel barrier layer 140 , and a spin torque active layer 120 . Silver includes a W-X alloy, wherein W is tungsten, and wherein X includes at least one of a group 4 semiconductor and a group 3-5 semiconductor.

Therefore, the spin orbit torque-based magnetic tunnel junction according to the embodiment of the present invention uses a W-X alloy with large spin orbit coupling as the spin torque active layer 120 to enable spin orbit torque switching and to achieve high spin orbit torque efficiency at low resistivity. can have

A spin orbit-based magnetic tunnel junction according to an embodiment of the present invention includes a spin torque active layer 120 formed on a substrate 110 .

The substrate 110 may include a semiconductor substrate, and the semiconductor substrate may include silicon (Si), silicon-on-insulator (SOI), silicon germanium (SiGe), germanium (Ge), gallium arsenide (GaAs), or the like. can

The substrate 110 may include a native oxide layer on a surface in contact with the spin torque active layer 120 , and the native oxide layer formed on the surface of the substrate 110 may be amorphous.

According to an embodiment, at least one of a seed layer and a buffer layer may be further included on the substrate 110 .

Accordingly, the seed layer and the buffer layer may be formed between the substrate 110 and the active layer.

The seed layer may be formed on the substrate 110 or on the spin torque active layer 120 , and the seed layer is a material that allows crystal growth, and allows the magnetic material to grow in a desired crystal direction. .

The seed layer may include at least one of tantalum (Ta), ruthenium (Ru), titanium (Ti), palladium (Pd), platinum (Pt), magnesium (Mg), cobalt (Co), aluminum (Al), and tungsten (W). It may include one, but is not limited thereto. Preferably, the seed layer may be 5 nm Ta.

The buffer layer may be formed under the spin torque active layer 120 , and the buffer layer may be formed under the spin torque active layer 120 to improve crystallinity of the spin torque active layer 120 .

In addition, a buffer layer may be formed to resolve the lattice constant mismatch of the layers.

Also, the seed layer and the buffer layer are not separated from each other and may be formed as a single layer. For example, the buffer layer may also function as a seed layer.

The buffer layer may include at least one of Ta, W, and Pd, but is not limited thereto. Preferably, the buffer layer may be 10 nm of Pd or 2 nm of Ta.

The spin torque active layer 120 may be used as an electrode providing an in-plane current in contact with the free layer 130 , and may cause a spin Hall effect or a Rashba effect by providing an in-plane current.

The spin torque active layer 120 provides a spin polarization current, and applies a spin orbit torque to the free layer 130 by the spin Hall effect or Rashba effect of the spin torque active layer 120 to reverse the magnetization of the free layer 130 . can induce In addition, the spin torque active layer 120 provides the free layer 130 with spin accumulation aligned in the magnetization direction of the spin torque active layer 120 , and the spin accumulation provides a deterministic switching effect or additional torque. effect can be provided.

In addition, the current driven in-plane through the spin-torque active layer 120 and the accompanying spin orbit interactions may result in a spin orbit magnetic field H. This spin orbit magnetic field (H) is equal to the spin orbit torque (T) on magnetization. Therefore, torque and magnetic field may be referred to interchangeably as spin orbital magnetic field and spin orbital torque. This reflects the fact that spin orbit interactions are the source of spin orbit torque and spin orbit magnetic field. Spin orbital torque may be generated with respect to the current driven in the plane of the spintorque active layer 120 and the spin orbital interaction.

The spin torque active layer 120 may have a strong spin-orbit interaction and may be an electrode that can be used when switching the magnetic moment of the free layer 130 .

In addition, the spin torque active layer 120 may facilitate switching the magnetic field in the free layer 130 , and the spin torque active layer 120 changes the polarity direction of the magnetic field in the free layer 130 , thereby providing a spin transfer torque. memory can be implemented.

Accordingly, the spin orbit torque-based magnetic tunnel junction according to the embodiment of the present invention uses a spin orbit torque (SOT) for switching the free layer 130 using a spin current to operate the MRAM memory cell. can

Spin orbital torque-based magnetic tunnel junction according to an embodiment of the present invention is a spin torque active layer 120 of a W-X alloy (where W is tungsten, and X includes at least one of a group 4 semiconductor and a group 3-5 semiconductor) ) can be used, and thus, perpendicular magnetic anisotropy (PMA) can be maintained in various heat treatment temperature ranges.

Preferably, the group 4 semiconductor may include at least one of carbon (C), silicon (Si), germanium (Ge), tin (Sn), or an alloy thereof, and the group 3-5 semiconductor is GaAs, It may include at least one of GaP, InP, InGaAlN, and GaN, but is not limited thereto.

Preferably, in the spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention, a tungsten (W)-silicon (Si) alloy may be used as the spin torque active layer 120 .

More specifically, the spin orbital torque (SOT) is represented by the Spin-Hall Effect and the Rashba Effect by the spin orbital interaction, and this phenomenon can be strongly proportional to the atomic number. have. Therefore, in the past, studies focusing on heavy metal materials (W, Ta, Pt, etc.) have been conducted, and studies such as alloys or insertions of various materials are being made to further improve the properties and efficiency of a single heavy metal material.

Therefore, from the spintronics point of view, tungsten is a material with excellent spin-orbit torque (SOT) expression. In semiconductor materials such as Ga-As, groups 4 and 3-5), the spin-Hall effect and the Rashba effect, which are known causes of spin-orbit torque, exist. Torque switching is possible and it can have high spin orbit torque efficiency at low resistivity.

Preferably, tungsten (W) and silicon (Si) are essential materials for the semiconductor process, and the W-Si alloy also has low contact resistance when heat-treated at a high temperature and is a very friendly material for the semiconductor process, so the spin torque active layer ( 120) as a W-Si alloy.

The X element included in the spin torque active layer 120 of the spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention may be a semiconductor material, and the X element may exhibit an extrinsic spin-Hall effect.

Therefore, as the content of X (e.g., silicon) composition in tungsten increases due to the extrinsic spin-Hall effect of X, which is partially present as an impurity inside tungsten, the spin-Hall angle called spin orbit torque efficiency. (spin hall angle) may be increased.

In addition, electron scattering is increased by X, which is partially present as an impurity in tungsten, and as the composition content of X in tungsten increases, the specific resistance of the W-X alloy thin film may be increased.

In the spin orbit torque-based magnetic tunnel junction according to the embodiment of the present invention, the switching current may be reduced as the composition content of X included in the W-X alloy increases.

A switching current due to a spin-orbit torque (SOT) may be expressed by Equation 1 below.

[Equation 1]

는 스핀궤도 토크에 의한 스위칭 전류,

는 스핀 홀 각도라 불리는 스핀 토크의 효율,

는 포화자화,

는 자성층의 두께,

는 전류가 인가되는 비자성층의 단면적,

는 일축 이방성 자기장의 크기,

는 스위칭 실험 시 필요한 외부 자기장의 크기를 의미한다.In Equation 1,

is the switching current by the spin orbit torque,

is the efficiency of the spin torque, called the spin Hall angle,

is the saturation magnetization,

is the thickness of the magnetic layer,

is the cross-sectional area of the non-magnetic layer to which the current is applied,

is the magnitude of the uniaxial anisotropic magnetic field,

is the magnitude of the external magnetic field required for the switching experiment.

가 증가되고, 일축 이방성 자기장의 크기인

가 감소되어 스위칭 전류가 감소될 수 있다.As the compositional content of X in the WX alloy increases, the spin torque efficiency is

is increased, and the magnitude of the uniaxial anisotropic magnetic field is

is reduced, so that the switching current may be reduced.

In addition, the composition content of X included in the W-X alloy may be 0.1 at% to 10.6 at%. However, the composition content of X in the W-X alloy is not limited thereto, and may be adjusted according to the X material.

As the composition content of X increases in the W-X alloy, perpendicular magnetic anisotropy may be weakened, and there is a problem in that perpendicular magnetic anisotropy is lost when out of a specific composition content (eg, 10.6 at%) range.

Preferably, the composition of X in the W-X alloy can be adjusted according to the temperature of the heat treatment to be carried out later, and when the temperature of the heat treatment is 300 ° C or 400 ° C, the composition of X is 0.1 at% to 9.6 at%, Orthogonal magnetic anisotropy is expressed, and in the case of 500° C., when it is 0.1 at% to 8.6 at%, perpendicular magnetic anisotropy may be expressed. However, the composition content of X in the W-X alloy according to the heat treatment temperature is not limited thereto, and may be adjusted according to the X material.

If the composition content of X in the W-X alloy is less than 0.1 at%, it is the same as 100 at% of tungsten, and since it is a conventional tungsten-based spin orbit torque material that does not contain X, the spin orbit torque efficiency may be lowered.

When the temperature of the heat treatment is 300 ° C or 400 ° C, if the content of the composition of X in the W-X alloy exceeds 9.6 at%, the perpendicular magnetic anisotropy is lost as well as the magnetic layer (free layer and fixed layer) formed on the W-X alloy thin film There is a problem in that this magnetic property is lost and thus it cannot be used as a magnetic tunnel junction device.

In addition, when the temperature of the heat treatment is 500 ° C, if the content of the composition of X in the W-X alloy exceeds 8.6 at%, not only loses perpendicular magnetic anisotropy, but also the magnetic layer (free layer and fixed layer) formed on the W-X alloy thin film There is a problem in that it cannot be used as a magnetic tunnel junction device due to loss of magnetic properties.

For example, when a tungsten (W)-silicon (Si) alloy is used as the spin torque active layer 120, the composition ratio of silicon in which perpendicular magnetic anisotropy is expressed is the composition ratio of silicon when the heat treatment temperature is 300°C ( x, where x is a real number) may be 0.1 at% ≤ x ≤ 9.6 at%, and when the heat treatment temperature is 400 ° C, the composition ratio of silicon (x) may be 0.1 at% ≤ x ≤ 9.6 at%, When the heat treatment temperature is 500° C., the composition ratio (x) of silicon may be 0.1 at% ≤ x ≤ 8.6 at%.

In the spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention, the switching current may be reduced as the heat treatment temperature at which perpendicular magnetic anisotropy is expressed increases.

가 증가되고, 일축 이방성 자기장의 크기인

가 감소되므로 스위칭 전류가 감소될 수 있다.The magnetic tunnel junction based on spin orbital torque according to an embodiment of the present invention shows that the spin torque efficiency increases as the heat treatment temperature increases.

is increased, and the magnitude of the uniaxial anisotropic magnetic field is

Since is reduced, the switching current may be reduced.

In addition, when the heat treatment temperature is increased, X (eg, silicon) atoms, which were partially present as impurities in the tungsten, are melted into the tungsten structure to form an intermetallic compound, thereby structurally stabilizing and reducing the specific resistance.

The heat treatment temperature at which perpendicular magnetic anisotropy is expressed may be 300 °C to 500 °C.

Since the BEOL (Back End Of Line) process included in the semiconductor device process involves heat treatment at 300° C. to 400° C., it is essential to develop a device capable of maintaining magnetic properties even at the corresponding temperature.

Therefore, in the spin orbit torque-based magnetic tunnel junction according to the embodiment of the present invention, in order to express perpendicular magnetic anisotropy in the CoFeB/MgO (free layer/tunnel barrier layer) structure, heat treatment at least 250° C. to 300° C. Since the crystallization of the layer) must proceed, the heat treatment must be carried out at 300°C or higher. There is a loss problem.

In the spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention, the spin torque efficiency can be adjusted according to the thickness of the spin torque active layer 120 , and as the thickness of the spin torque active layer 120 increases from 1 nm, Since the spin torque efficiency is increased and then saturated, the thickness of the spin torque active layer 120 may have the maximum spin torque efficiency in the range of 5 nm to 7 nm.

Preferably, in the case of W, since it may have an optimal thickness at 5 nm in order to maintain a beta phase having high spin torque efficiency, the thickness of the spin torque active layer 120 may be 5 nm.

The spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention includes the free layer 130 formed on the spin torque active layer 120 .

In the free layer 130 , the magnetization is not fixed in one direction, but may be changed in one direction opposite to the magnetization. The free layer 130 may have the same (ie, parallel) magnetization direction as the pinned layer 150 or may have the opposite (ie, antiparallel) magnetization direction.

The magnetic tunnel junction may be used as a memory device by matching information to resistance values that change according to the magnetization arrangement of the free layer 130 and the pinned layer 150 .

For example, when the magnetization direction of the free layer 130 is parallel to the pinned layer 150 , the resistance value of the magnetic tunnel junction decreases, and this case may be defined as data '0'. Also, when the magnetization direction of the free layer 130 is antiparallel to the pinned layer 150 , the resistance value of the magnetic tunnel junction increases, and this case may be defined as data '1'.

In the spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention, the free layer 130 may have perpendicular magnetic anisotropy (PMA).

For example, when the magnetization direction of the free layer 130 is the negative z-axis direction, the rotation direction of the current may be clockwise in order to reverse the magnetization in the positive z-axis direction. The torque applied to the magnetic moment of the free layer 130 due to the in-plane current may be referred to as a spin orbital torque.

The free layer 130 may include a material having an interface perpendicular magnetic anisotropy. Interfacial perpendicular magnetic anisotropy refers to a phenomenon in which a magnetic layer having intrinsic horizontal magnetization characteristics has a perpendicular magnetization direction due to the influence from an interface with another layer adjacent thereto.

The free layer 130 may include at least one of cobalt (Co), iron (Fe), and nickel (Ni). In addition, the free layer 130 includes boron (B), zinc (Zn), aluminum (Al), titanium (Ti), ruthenium (Ru), tantalum (Ta), silicon (Si), silver (Ag), gold ( Au), copper (Cu), carbon (C), and may further include at least one of non-magnetic materials such as nitrogen (N).

For example, the free layer 130 may include CoFe or NiFe, but may further include boron (B). In addition, the reference layer 126 and the free layer 122 may further include at least one of titanium (Ti), aluminum (Al), silicon (Si), magnesium (Mg), tantalum (Ta), and silicon (Si). can

According to an embodiment, the free layer 130 may include at least one of a material having an L10 crystal structure, a material having a Hexagonal Close Packed lattice (HCP), and an amorphous Rare-Earth Transition Metal (RE-TM) alloy. may include

The thickness of the free layer 130 may be 0.9 nm in order to express perpendicular magnetic anisotropy, but is not limited thereto.

The spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention includes the tunnel barrier layer 140 formed on the free layer 130 .

The tunnel barrier layer 140 separates the free layer 130 and the pinned layer 160 , and enables quantum mechanical tunneling between the free layer 130 and the pinned layer 160 .

The tunnel barrier layer 140 may be interposed between the free layer 130 and the pinned layer 150 . The tunnel barrier layer 140 is an oxide of magnesium (Mg), an oxide of titanium (Ti), an oxide of aluminum (Al), an oxide of magnesium-zinc (MgZn), an oxide of magnesium-boron (MgB), and titanium (Ti). It may include at least one of a nitride of and a nitride of vanadium (V). For example, the tunnel barrier layer 140 may include crystalline magnesium oxide (MgO).

The thickness of the tunnel barrier layer 140 may be 1.0 nm in order to express perpendicular magnetic anisotropy, but is not limited thereto.

The spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention includes the pinned layer 150 formed on the tunnel barrier layer 140 .

The pinned layer 150 may have a fixed magnetic moment during a write operation of the magnetic memory device. For example, the magnetic moment of the pinned layer 150 may not be switched by the spin orbit torque caused by currents flowing through the spin torque active layer 120 .

The pinned layer 150 may include a material having an interface perpendicular magnetic anisotropy.

Interfacial perpendicular magnetic anisotropy refers to a phenomenon in which a magnetic layer having intrinsic horizontal magnetization characteristics has a perpendicular magnetization direction due to the influence from an interface with another layer adjacent thereto. The pinned layer 150 may include at least one of cobalt (Co), iron (Fe), and nickel (Ni).

In addition, the pinned layer 150 includes boron (B), zinc (Zn), aluminum (Al), titanium (Ti), ruthenium (Ru), tantalum (Ta), silicon (Si), silver (Ag), and gold (Au). ), copper (Cu), carbon (C), and may further include at least one of non-magnetic materials such as nitrogen (N).

For example, the pinned layer 150 may include CoFe or NiFe, but may further include boron (B). In addition, the reference layer 126 and the free layer 122 may further include at least one of titanium (Ti), aluminum (Al), silicon (Si), magnesium (Mg), tantalum (Ta), and silicon (Si). can

The pinned layer 150 may have a single layer structure. Depending on the embodiment, the pinned layer 150 may include a synthetic antiferromagnetic material having ferromagnetic layers separated by nonmagnetic layer(s).

According to an embodiment, the pinned layer 150 includes at least one of a material having an L10 crystal structure, a material having a Hexagonal Close Packed lattice (HCP), and an amorphous Rare-Earth Transition Metal (RE-TM) alloy. can do.

The pinned layer 150 may be formed to be thicker than the free layer 130 so that switching does not easily occur.

The spin orbit torque-based magnetic tunnel junction may further include a capping layer 160 on the pinned layer 150 , and preferably, Ta may be used for the capping layer 160 .

The capping layer 160 may be used as an anti-oxidation layer, and may be deposited with a thickness of 2 nm to prevent the properties of the magnetic layer (free layer and pinned layer) from being reduced by natural oxidation.

When the thickness of the capping layer 160 is formed to be thicker than 2 nm, the anti-oxidation effect may be increased. 130) and the thickness of the tunnel barrier layer 140) must be adjusted.

In the spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention, the spin torque active layer 120 , the free layer 130 , the tunnel barrier layer 140 , and the pinned layer 150 have a cross shape in plan view. can

In addition, the spin torque active layer 120 of the spin orbit torque-based magnetic tunnel junction according to the embodiment of the present invention has a cross shape in plan view, and the free layer 130, the tunnel barrier layer 140 and the pinned layer ( 150 ) may be disposed in the form of an island in the center of the spin torque active layer 120 having a cross shape.

Referring to FIG. 2 , the spin torque active layer 120 has a cross shape in plan view, and the free layer 130 , the tunnel barrier layer 140 , and the pinned layer 150 have a cross shape spin torque active layer 120 . ) will be described in detail with respect to the spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention disposed in the form of an island in the center of the present invention.

The spin orbit torque-based magnetic tunnel junction electrically measures the change in resistance according to the magnetization direction of the magnetic layer, and all layers have a cross shape (spin torque active layer 120, free layer 130, tunnel barrier layer 140 and When the pinned layer 150 has a cross shape when viewed in a plan view), the volume of the magnetic layer is increased, so that a signal (signal) is easily generated, which can facilitate characterization.

On the other hand, the spin torque active layer 120 has a cross shape in plan view, and the free layer 130 , the tunnel barrier layer 140 , and the pinned layer 150 are in the center of the cross shape spin torque active layer 120 . When arranged in an island form, it is used only for switching using the spin-orbit torque. It prevents the magnetization direction of the free layer from being changed by domain wall propagation rather than the spin-orbit torque and completely spin-orbits. Magnetization reversal due to orbital torque can be observed.

In addition, when the free layer 130 , the tunnel barrier layer 140 , and the pinned layer 150 are disposed in an island shape, after all the layers are manufactured in a cross shape, the etching step must be performed once more, and while the etching is performed, When the spin-torque active layer starts to be exposed, the etching must be stopped immediately, so know-how in device fabrication is required.

2 is a plan view illustrating a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention.

The cross-shaped spin torque active layer 120 may include a first conductive line 121 and a second conductive line 122, such that the first conductive line 121 and the second conductive line 122 cross each other. can be formed.

Accordingly, in the magnetization switching method, a first AC current jx having a first frequency is applied to the first conductive line 121 , and a second AC current jy having a first frequency is applied to the second When applied to the conductive line 122 , the free layer 130 may perform magnetization reversal.

When a first current having a first angular frequency ω is injected into the first conductive line 121 and a second current having a first angular frequency ω is injected into the second conductive line 122 , free At positions where the layer 130 , the tunnel barrier layer 140 , and the pinned layer 150 are disposed, the total current vector may rotate with time.

If we look at the problem from the point of view of a rotating coordinate system like the phase of the total current vector, AC current turns into a DC current problem. On the other hand, from the standpoint of the rotating coordinate system, an effective magnetic field in the vertical direction corresponding to the rotational angular velocity appears. That is, the effect of alternating current is converted into a problem of direct current in a system with an effective magnetic field in the vertical direction. In this case, the magnetization of the free layer can be reversed very easily due to the effect of the effective magnetic field in the vertical direction.

The first conductive line 121 and the second conductive line 122 may be formed of a material that induces a Spin Hall effect or a Rashiba effect. When a first current flows in the first conductive line 112 , spin polarization perpendicular to the traveling direction of the first conductive line 121 occurs, and the spin current proceeds in the free layer direction (z-axis direction). .

The first conductive line 121 may have a line shape extending along the x-direction. The second conductive line 122 may have a line shape crossing the first conductive line 121 . For example, the second conductive line 122 may have a line shape extending along the y-direction.

The first conductive line 121 and the second conductive line 122 may cross each other at a point and may be connected to each other. For example, the first conductive line 121 and the second conductive line 122 may be positioned on the same plane (ie, an x-y plane).

In the spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention, by patterning the spin torque active layer 120 in a cross shape, the characteristics due to the spin Hall effect can be electrically measured, and the movement of magnetization due to the spin torque can be measured. Voltage can be measured in a direction perpendicular to the current injection direction.

3 is a flowchart illustrating a method of manufacturing a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention.

Since the method for manufacturing a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention includes the same components as the spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention, the same components will be omitted. .

First, in the method of manufacturing a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention, the step ( S110 ) of forming a spin torque active layer on a substrate is performed.

The substrate may be a silicon substrate, and a native oxide layer may be formed on the surface of the silicon substrate, and according to an embodiment, the native oxide layer may be formed by CVD, PVD, or thermal oxidation.

According to an embodiment, the method of manufacturing a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention includes the steps of forming a seed layer on the substrate and forming a buffer layer on the substrate before forming the spin torque active layer on the substrate At least one of the steps may be performed.

The seed layer and the buffer layer include physical vapor deposition (PVD) including sputtering, molecular beam epitaxy (MBE), pulsed laser deposition (PLD), and atomic layer deposition (ALD). layer deposition), electron beam (e-beam) epitaxy, chemical vapor deposition (CVD), or low pressure CVD (LPCVD), ultrahigh vacuum CVD (UHVCVD) or reduced pressure CVD ( Derived CVD processes including RPCVD (reduced pressure CVD), electroplating, coating, or any combination thereof.

The step of forming the spin torque active layer on the substrate (S110) is a W-X alloy (where W is tungsten, and X is a group 4 semiconductor) on the substrate disposed in the vacuum chamber by sputtering the W target and the X target simultaneously in the vacuum chamber. and at least one of a group 3-5 semiconductor) to form a thin film.

Preferably, a tungsten-silicon alloy thin film may be formed on a substrate disposed in a vacuum chamber by a co-deposition method in which the W target and the X target are simultaneously sputtered in the vacuum chamber.

In the method of manufacturing a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention, the composition of the W-X alloy thin film may be adjusted according to the power and thickness of the W target and the X target.

First, the composition of the W-X alloy thin film may be adjusted according to the power of the W target and the X target.

The power of the W target may be 0.1 W to 85 W (0 W/cm ² to 4.19 W/cm ² ), and if it is less than 0.1 W, there is a problem that W is not deposited, and if the W target power exceeds 85 W, W There is a problem in that cracks occur due to too much energy being applied to the target.

The power of the X target may be 0.1 W to 86.2 W (0.1 W/cm ² to 4.25 W/cm ² ), and if it is less than 0.1 W, there is a problem that X is not deposited, and if the X target power exceeds 86.2 W, X There is a problem in that cracks occur due to too much energy being applied to the target.

For example, the volume per mole (mol/cm ³ ) is calculated using the physical properties (density, atomic weight) of each material (W and X) and divided by the thickness to deposit a specific thickness. After calculating the value of moles, if the thickness of the entire WX alloy thin film is fixed and the thickness of each material (W and X) is adjusted, the molar value of each material (W and X) is calculated, and using this, WX The composition (at%) of the alloy thin film can be determined.

Assuming that the W target and X target power are in direct proportion to the deposition power and deposition rate of each target, the power at which the deposition time of the two materials becomes the same using the deposition rate when depositing at 50 W (2.47 W/cm ² ) can be deposited with

For example, when using silicon as X to form a W-Si alloy thin film, in the case of sputtering equipment, the deposition rates of tungsten (W) and silicon (Si) at a power of 50 W are 0.045778 nm/s and 0.045778 nm/s, respectively. Since it is 0.013678 nm/s, when the thickness of the W-Si alloy thin film is fixed at 5 nm to match the atomic ratio of tungsten and silicon to 50:50, the thickness of tungsten and silicon can be 3.72 nm and 1.28 nm, respectively .

If both materials are deposited at 50 W in consideration of the deposition rate, it takes 81.3 seconds and 93.6 seconds to deposit each thickness. By adjusting the power, the deposition can proceed by setting the power that takes the same time to deposit 3.72 nm of tungsten and 1.28 nm of silicon.

In this case, the power of the tungsten target may be 60 W (2.96 W/cm ² ), and the power of the silicon target may be 69.1 W (3.41 W/cm ² ).

In addition, when the thickness of the W-Si alloy thin film is 5 nm, the thickness of tungsten may be 1.2 nm to 4.9 nm, and the thickness of silicon may be 0.1 nm to 3.8 nm.

In addition, the deposition time for sputtering the tungsten target and the silicon target at the same time may be 59 seconds to 231 seconds.

The initial vacuum degree of the sputtering chamber may be 5Х10 ^-9 Torr, and when 39 sccm of argon is flowed, the working pressure may be 1.4 mTorr.

Accordingly, the composition content of X included in the W-X alloy may be 0.1 at% to 10.6 at%.

For example, when a tungsten (W)-silicon (Si) alloy is used as the W-X alloy, the composition ratio of silicon exhibiting perpendicular magnetic anisotropy is when the heat treatment temperature is 300° C., the composition ratio of silicon (x, where x is a real number) may be 0.1 at% ≤ x ≤ 9.6 at%, and when the heat treatment temperature is 400 ° C, the composition ratio of silicon (x) may be 0.1 at% ≤ x ≤ 9.6 at%, and the heat treatment temperature is 500 When it is ℃, the composition ratio (x) of the silicon may be 0.1 at% ≤ x ≤ 8.6 at%.

The forming of the spin torque active layer on the substrate may further include patterning the W-X alloy thin film in a cross shape.

The W-X alloy thin film may be patterned in a cross shape by performing photolithography and etching.

A method of manufacturing a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention includes the steps of forming a free layer on the spin torque active layer (S120), forming a tunnel barrier layer on the free layer (S130), and a tunnel barrier The step of forming the fixed layer formed on the layer (S140) proceeds.

The free layer, the tunnel barrier layer, and the free layer are each formed by physical vapor deposition (PVD) including sputtering, molecular beam epitaxy (MBE), pulsed laser deposition (PLD), atom Atomic layer deposition (ALD), electron beam (e-beam) epitaxy, chemical vapor deposition (CVD), or low pressure CVD (LPCVD), ultrahigh vacuum (UHVCVD) CVD) or a derivative CVD process including reduced pressure CVD (RPCVD), electroplating, or any combination thereof.

According to an embodiment, in the method for manufacturing a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention, the step of forming the pinned layer formed on the tunnel barrier layer (S140) is performed, and then the capping layer is formed on the pinned layer. You can proceed with the steps to

The capping layer is formed by physical vapor deposition (PVD) including sputtering, molecular beam epitaxy (MBE), pulsed laser deposition (PLD), and atomic layer deposition (ALD). ), electron beam (e-beam) epitaxy, chemical vapor deposition (CVD), or low pressure CVD (LPCVD), ultrahigh vacuum CVD (UHVCVD, ultrahigh vacuum CVD) or reduced pressure CVD (RPCVD, reduced pressure CVD), a method comprising electroplating, coating, or any combination thereof.

In order to develop perpendicular magnetic anisotropy to the free layer and the pinned layer, a step (S150) of heat treatment is performed.

In the method of manufacturing a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention, a heat treatment step (S150) is performed to express perpendicular magnetic anisotropy in the free layer and the pinned layer.

가 증가되고, 일축 이방성 자기장의 크기인

가 감소되므로 스위칭 전류가 감소될 수 있다.In the method for manufacturing a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention, as the heat treatment temperature increases, the spin torque efficiency is

is increased, and the magnitude of the uniaxial anisotropic magnetic field is

Since is reduced, the switching current may be reduced.

In addition, when the heat treatment temperature is increased, X (eg, silicon) atoms, which were partially present as impurities in the tungsten, are melted into the tungsten structure to form an intermetallic compound, thereby structurally stabilizing and reducing the specific resistance.

The heat treatment temperature at which perpendicular magnetic anisotropy is expressed may be 300 °C to 500 °C.

Since the BEOL (Back End Of Line) process included in the semiconductor device process includes heat treatment at 300° C. to 400° C., it is essential to develop a device capable of maintaining magnetic properties even at the corresponding temperature.

Therefore, in the method of manufacturing a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention, in order to exhibit perpendicular magnetic anisotropy in a CoFeB/MgO (free layer/tunnel barrier layer) structure, heat treatment is performed at at least 250° C. to 300° C. Since the crystallization of CoFeB (free layer) must proceed, heat treatment must be carried out at 300°C or higher. There is a problem of losing the characteristics of

Experimental Example 1: Device Manufacturing

[Example 1-1]: Si/SiO ₂ /W-Si/CoFeB/MgO/Ta (multilayer thin film structure) production

A tungsten (W) target is sputtered on a Si substrate (Si/SiO ₂ ) with an amorphous natural oxide layer formed on the surface, and a silicon (Si) target is sputtered together at the same time to form a 5 nm tungsten-silicon alloy layer (W-Si, spin Torque active layer) was formed, and at this time, DC and AC magnetron sputtering were used for the tungsten target and the silicon target, respectively, and the sputtering power of each element to be sputtered at the same time while the flow rate of argon gas was fixed was adjusted to form the tungsten-based alloy thin film. The composition was adjusted, and the size of the target used to fabricate the tungsten-silicon alloy layer was 2 inches in diameter.

A 0.9 nm CoFeB free layer was formed on the tungsten-silicon alloy layer using a Co ₄₀ Fe ₄₀ B ₂₀ (at%) target, followed by a 1 nm MgO insulating layer and a 2 nm Ta capping layer.

Accordingly, Si/SiO ₂ /W-Si/CoFeB/MgO/Ta (substrate/native oxide layer/spintorque active layer/free layer/tunnel barrier/capping layer) as shown in FIG. 4 was formed.

In manufacturing the spin orbit torque-based magnetic tunnel junction, direct current (dc) magnetron sputtering was used for laminating the metal layer, and alternating current (ac) magnetron sputtering was used for laminating the insulator, and the initial vacuum (base pressure) was Each was 5x10 ^-9 Torr or less, and was deposited in an argon (Ar) atmosphere. The thickness of each layer was controlled using the deposition time and sputtering power.

4 is a cross-sectional view illustrating a structure for measuring spin orbit torque efficiency of a spin orbit torque based magnetic tunnel junction according to an embodiment of the present invention.

[Example 1-2]: Si/SiO ₂ /W-Si/CoFeB/MgO/Ta (cross pattern structure) production

The multilayer thin film structure including the spin torque active layer, the CoFeB free layer, and the MgO insulating layer were all prepared in the same manner as in Example 1-1. As shown in FIG. 11a, the spin orbit torque efficiency and specific resistance were measured by patterning the entire structure of the device in a cross shape.

[Example 1-3]: Si/SiO ₂ /W-Si/CoFeB/MgO/Ta (free layer magnetic tunnel junction structure) manufacturing

The multilayer thin film structure including the spin torque active layer, the CoFeB free layer, and the MgO insulating layer were all prepared in the same manner as in Example 1-1. After patterning the entire structure of the device in a cross shape as shown in FIG. 17A, all layers except the spin torque active layer were formed in an island shape on the spin orbit torque active layer. Magnetization reversal due to current-applied spin orbital torque was measured using the specimen.

[Example 2]

A 25 nm tungsten-silicon alloy layer (W-Si, spin torque active layer) single layer was formed, and was prepared in the same manner as in Example 1-1 except for the patterning process.

[Example 3]: CoFeB 4/W ₉₆ Si _4.0 1.5/CoFeB 0.9/MgO 1/Ta 2 (unit: nm)

A magnetic layer having an easy magnetization axis in the in-plane direction of 4 nm using a Co ₄₀ Fe ₄₀ B ₂₀ (at%) target on a Si substrate (Si/SiO ₂ ) having an amorphous natural oxide layer formed on the surface was formed by direct current magnetron sputtering. to deposit In this case, the thickness of the magnetic layer may be changed in a state in which the easy axis of magnetization is in the in-plane direction.

A tungsten (W) target was sputtered and a silicon (Si) target was sputtered at the same time to form a tungsten-silicon alloy layer (W-Si, spin torque active layer) of 1.5 nm, at this time, the tungsten target and the silicon target were each DC , alternating current magnetron sputtering was used, and the composition of the tungsten-based alloy thin film was adjusted by adjusting the sputtering power of each sputtering element at the same time while the flow rate of argon gas was fixed. It is 2 inches. The thickness of the tungsten-silicon alloy layer can also be varied (thickness of 1 nm, 1.5 nm, 2 nm, 3 nm).

A 0.9 nm CoFeB free layer was formed on the tungsten-silicon alloy layer using a Co ₄₀ Fe ₄₀ B ₂₀ (at%) target, followed by a 1 nm MgO insulating layer and a 2 nm Ta capping layer.

Accordingly, Si/SiO ₂ /CoFeB/W _- Si/CoFeB/MgO/Ta (substrate/magnetic layer having an easy axis of magnetization in the in-plane direction/ A native oxide layer/spintalk active layer/free layer/tunnel barrier/capping layer) was formed.

In manufacturing the spin orbit torque-based magnetic tunnel junction, direct current (dc) magnetron sputtering was used for laminating the metal layer, and alternating current (ac) magnetron sputtering was used for laminating the insulator, and the initial vacuum (base pressure) was Each was 5x10 ^-9 Torr or less, and was deposited in an argon (Ar) atmosphere. The thickness of each layer was controlled using the deposition time and sputtering power.

As in Example 1-2 of the present invention, in the spin orbit torque-based magnetic tunnel junction, the entire thin film structure was patterned in a cross pattern in order to measure the spin orbit torque efficiency.

Thereafter, in order to measure magnetization reversal due to current-applied spin orbital torque, all layers except for the spin torque active layer were formed in an island form on the spin torque active layer as in Example 1-3.

[Experimental Example 4]: heat treatment

All Si/SiO ₂ /W-Si/CoFeB/MgO/Ta as shown in FIG. 4 were formed, and then heat treatment was performed at a temperature of 300° C., 400° C. and 500° C. for 1 hour, and initial vacuum during heat treatment is in the 10 ^-6 Torr band, and an external magnetic field of 6 kOe was applied in a direction perpendicular to Si/SiO ₂ /W-Si/CoFeB/MgO/Ta (spin orbit torque-based magnetic tunnel junction) during the heat treatment.

A cross-shaped hole with a size of 5 x 35 μm ² was performed using a photolithography process to check the efficiency of spin orbital torque for a specimen maintaining perpendicular magnetic anisotropy after heat treatment at 300°C, 400°C, and 500°C A bar (Hall bar) was manufactured. After fabricating a cross-shaped Hall bar using the same specimen, the CoFeB/MgO/Ta layer was fabricated in the form of an island with a diameter of 4 μm, and magnetization reversal by spin-orbit torque was measured.

5 to 10 are magnetic hysteresis curves according to heat treatment temperature measured with a vibrating sample magnetometer (VSM).

5 is a spin orbit torque-based magnetic tunnel junction according to an embodiment of the present invention as shown in FIG. 4 in which heat treatment was performed at 300° C. for 1 hour (hereinafter, W-Si/CoFeB/W-Si/CoFeB/according to Example 1-1). When a magnetic field is applied in the out-of-plane direction to the MgO/Ta structure), the magnetic hysteresis curve according to the silicon content (0at% to 10.6 at%) of the spin torque active layer is obtained 6 is a graph showing a magnetic hysteresis curve according to the silicon content (0at% to 10.6 at%) of the spin torque active layer when a magnetic field is applied in the in-plane direction of the thin film.

5 and 6 are hysteresis curves measured by applying a magnetic field in the out-of-plane and in-plane directions of the thin film using a vibrating sample magnetometer (VSM). to be.

5 and 6, when the thickness of the tungsten-silicon alloy is fixed to 5 nm in the W-Si/CoFeB/MgO/Ta structure according to Example 1-1 in which the heat treatment was performed at 300° C., the composition of silicon It can be seen that perpendicular magnetic anisotropy is expressed from 0 at% to 10.6 at%.

7 shows the silicon content (0at) of the spin torque active layer when a magnetic field is applied in the direction perpendicular to the plane of the thin film to the W-Si/CoFeB/MgO/Ta structure according to Example 1-1, which was heat treated at 400° C. for 1 hour. % to 10.6 at%) is a graph showing the hysteresis curve, and FIG. 8 is a hysteresis curve according to the silicon content (0at% to 10.6 at%) of the spin torque active layer when a magnetic field is applied in the in-plane direction of the thin film. is a graph showing

7 and 8, when the thickness of the tungsten-silicon alloy is fixed to 5 nm in the W-Si/CoFeB/MgO/Ta structure according to Example 1-1 in which the heat treatment was performed at 400° C., the composition of silicon It can be seen that the perpendicular magnetic anisotropy is maintained from 0 at% to 10.6 at%, and the perpendicular magnetic anisotropy disappears thereafter.

In addition, in a composition range in which the composition of silicon is 10.6 at% or more, as the composition range of silicon increases, it does not have anisotropy and magnetic properties may be reduced.

9 shows the silicon content (0at) of the spin torque active layer when a magnetic field is applied to the W-Si/CoFeB/MgO/Ta structure according to Example 1-1, which was heat treated at 500° C. for 1 hour in the direction perpendicular to the plane of the thin film. % to 10.6 at%) is a graph showing the hysteresis curve, and FIG. 10 is a hysteresis curve according to the silicon content (0 at% to 10.6 at%) of the spin torque active layer when a magnetic field is applied in the in-plane direction of the thin film. is a graph showing

9 and 10, when the thickness of the tungsten-silicon alloy is fixed to 5 nm in the W-Si/CoFeB/MgO/Ta structure according to Example 1-1 in which the heat treatment was performed at 500° C., the composition of silicon It can be seen that the perpendicular magnetic anisotropy is maintained from 0 at% to 10.6 at%, and the perpendicular magnetic anisotropy disappears thereafter.

열처리한 시편의 damping-like 토크, 500℃ 열처리한 시편의 field-like 토크의 효율이다.11A is a schematic diagram showing a W-Si/CoFeB/MgO/Ta structure according to Example 1-2 having perpendicular magnetic anisotropy, and FIG. 11B is a vacuum heat treatment at 300° C. and 500° C. for 1 hour, FIG. Spin trajectory of the device measured using a harmonics measurement method in the composition range of the tungsten-silicon alloy layer in the W-Si/CoFeB/MgO/Ta structure according to Example 1-2 having the perpendicular magnetic anisotropy shown in 11a It is a graph showing the efficiency of torque. At this time, DL _WS3 , FL _WS3 , DL _WS5 and FL _WS5 are respectively the damping-like torque of the specimen heat treated at 300°C, the field-like torque of the specimen heat treated at 300°C, and 500

The efficiency of the damping-like torque of the heat treated specimen and the field-like torque of the 500 °C heat treated specimen.

Referring to FIG. 11A , the W-Si/CoFeB/MgO layer according to Example 1-2 was patterned in a cross shape and then measured using a harmonics measurement method.

The multilayer thin film structure prepared by patterning the W-Si/CoFeB/MgO layer according to Example 1-2 in a cross shape can measure the voltage in the x and y directions when a current flows in the x direction, and the voltage in the x direction The resistivity of the silver material can be measured, and the y-direction voltage can measure the spin orbital torque efficiency of the material.

Referring to FIG. 11b , when the tungsten-silicon alloy layer was subjected to heat treatment at 500° C., it can be seen that the composition of all silicon increased compared to the case where a tungsten single layer was used (30%).

In particular, when the Si composition is 4.0 at%, it can be seen that the spin orbital torque efficiency of 0.58 is increased by about 100% compared to the tungsten single layer.

12 is a tungsten-silicon alloy in the W-Si/CoFeB/MgO/Ta structure according to Example 1-2 having the perpendicular magnetic anisotropy shown in FIG. 11a by performing vacuum heat treatment at 300° C. and 500° C. for 1 hour. It is a graph showing the electrical resistivity value of the alloy measured using a four-point probe in the composition range of the layer.

12 shows the W-Si layer was patterned in a cross shape and then measured using the harmonics measurement method.

Based on the assumption that no current flows in the insulating layer (MgO) and the capping layer (Ta) when a current is passed through the W-Si/CoFeB/MgO/Ta structure, the spin torque active layer (electrode) is free from the W-Si layer This is the result of calculating the specific resistance of the tungsten-silicon alloy layer by performing parallel resistance calculation of the layer CoFeB (ρ = 170 μΩ·cm).

Referring to FIG. 12 , the specific resistance increases as the composition of silicon increases for heat treatment conditions of 300° C. and 500° C., but when heat treatment is performed at 500° C., heat treatment is performed at 300° C. up to 7.6 at% of the silicon composition. It can be seen that the specific resistance of a single tungsten layer is lower than that of the tungsten single layer.

13 to 22 are measurements of the switching characteristics of the W-Si/CoFeB/MgO/Ta structure according to Example 1-3. Layers (free layers, tunnel barriers, etc.) excluding the spin torque active layer have a cross-shaped spin. After patterning in the form of an island in the center of the torque active layer, measurement was carried out.

13 shows when an external magnetic field of +100 Oe is applied to the W-Si/CoFeB/MgO/Ta structure according to Examples 1-3 having perpendicular magnetic anisotropy by vacuum heat treatment at 300° C. for 1 hour, tungsten- It is a graph showing switching characteristics according to the composition (unit: at%) of the silicon alloy layer, and FIG. 14 is a tungsten-switching according to the composition (unit: at%) of the silicon alloy layer when an external magnetic field of -100 Oe is applied. It is a graph showing characteristics.

Referring to FIGS. 13 and 14 , it can be seen that switching occurs at a current smaller than that of a tungsten single layer for all silicon compositions due to spin orbit torque switching characteristics according to the composition of the tungsten-silicon alloy layer.

15 shows that when an external magnetic field of +100 Oe is applied to the W-Si/CoFeB/MgO/Ta structure according to Examples 1-3 having perpendicular magnetic anisotropy by vacuum heat treatment at 500° C. for 1 hour, tungsten- It is a graph showing the switching characteristics according to the composition (unit: at%) of the silicon alloy layer, Figure 16 is when an external magnetic field of -100 Oe is applied, tungsten-switching according to the composition (unit: at%) of the silicon alloy layer It is a graph showing characteristics.

15 and 16 , it can be seen that the tungsten-silicon alloy layer has a spin orbital torque switching characteristic according to the composition, and the switching occurs at a current smaller than that of the tungsten single layer for all silicon compositions.

17A is a schematic view showing a W-Si/CoFeB/MgO/Ta structure according to Examples 1-3 having perpendicular magnetic anisotropy, and FIG. 17B is a vacuum heat treatment at 300° C. and 500° C. for 1 hour, vertical When an external magnetic field of ±100 Oe is applied to the W-Si/CoFeB/MgO/Ta structure according to Example 1-1 having magnetic anisotropy, the switching current density change according to the composition of the tungsten-silicon alloy layer, which is the spin torque active layer, It is the graph shown.

The switching current density was calculated using the magnitude of the current actually flowing through the tungsten-silicon alloy layer by calculating the parallel resistance by considering the change in resistivity according to the increase in the composition of silicon.

Referring to FIG. 17A , after patterning the W-Si layer in a cross shape, CoFeB/MgO was formed only at the cross section of the W-Si layer.

After patterning the W-Si layer in a cross shape, CoFeB/MgO is formed only at the cross-shaped intersection of the W-Si layer. Magnetization reversal due to spin orbital torque according to current injection can be observed. In the same structure, if a magnetic field is applied in the x direction, magnetization reversal of a magnetic field can be measured, and reversal of magnetization without a magnetic field can be measured if no magnetic field is applied.

Referring to FIG. 17B , it can be seen that the switching current decreases as the silicon composition increases.

More specifically, when heat treatment was performed at 300° C., when silicon was not included, the switching current density was 43.5 MA/cm ² , but when the composition of silicon (Si) was 9.6 at%, it decreased to 14.0 MA/cm ² became

When the heat treatment was performed at 500° C., when silicon was not included, the switching current density was 33.2 MA/cm ² , but when the composition of silicon (Si) was 7.4 at%, it was reduced to 10.8 MA/cm ² .

Therefore, it can be seen that when the heat treatment is performed at 500° C., it has a lower value for all compositions than the switching current density when the heat treatment is performed at 300° C.

18 is a view showing the change of an external magnetic field after heat treatment of the W-Si/CoFeB/MgO/Ta structure according to Examples 1-3 including a spin torque active layer having a silicon content of 0 at% at 300° C. for 1 hour; FIG. It is a graph measuring the switching current (current density), and FIG. 19 is a W-Si/CoFeB/MgO/Ta structure according to Example 1-3 including a spin torque active layer having a silicon content of 7.4 at% 1 at 300°C. After heat treatment for a period of time, it is a graph measuring the switching current (current density) according to the change in the external magnetic field, and FIG. 20 is W-Si according to Examples 1-3 including a spin torque active layer having a silicon content of 9.1 at%. This is a graph measuring the switching current (current density) according to the change in the external magnetic field after the /CoFeB/MgO/Ta structure was heat treated at 300° C. for 1 hour.

18 to 20 , while increasing the size from 10 Oe to 150 Oe, the value of the switching current or current density required for magnetization reversal decreases according to the applied external magnetic field, and spin orbit torque switching under all applied external magnetic fields phenomenon can be seen.

21 is a view showing the change of an external magnetic field after heat treatment of a W-Si/CoFeB/MgO/Ta structure according to Examples 1-3 including a spin torque active layer having a silicon content of 0 at% at 500° C. for 1 hour; It is a graph measuring the switching current (current density), and FIG. 22 is a W-Si/CoFeB/MgO/Ta structure according to Example 1-3 including a spin torque active layer having a silicon content of 7.4 at% at 500°C. After heat treatment for a period of time, it is a graph measuring the switching current (current density) according to the change in the external magnetic field, and FIG. 23 is W-Si according to Examples 1-3 including a spin torque active layer having a silicon content of 9.1 at%. This is a graph measuring the switching current (current density) according to the change in the external magnetic field after the /CoFeB/MgO/Ta structure was heat treated at 500° C. for 1 hour.

21 to 23 , it can be seen that the value of the switching current or current density required for magnetization reversal decreases according to the applied external magnetic field while increasing the size from 10 Oe to 150 Oe.

In addition, it can be seen that the spin orbit torque switching phenomenon appears under all applied external magnetic fields, and as compared with FIGS. 18 to 23 , when the heat treatment temperature increases, the switching current value decreases.

에서 1시간동안 진공 열처리를 진행한 뒤, 리더포드 후방산란(Rutherford Backscattering)을 이용한 W 내의 Si 함량을 도시한 그래프이며, 도 26은 텅스텐-실리콘 합금층의 실리콘 조성이 7.4 at%인 실시예 2에 따른 W-Si/CoFeB/MgO/Ta 구조체를 500℃에서 1시간동안 진공 열처리를 진행한 뒤, 리더포드 후방산란(Rutherford Backscattering)을 이용한 W 내의 Si 함량을 도시한 그래프이고, 도 27은 텅스텐-실리콘 합금층의 실리콘 조성이 9.1 at%인 실시예 2에 따른 W-Si/CoFeB/MgO/Ta 구조체를 500℃에서 1시간동안 진공 열처리를 진행한 뒤, 리더포드 후방산란(Rutherford Backscattering)을 이용한 W 내의 Si 함량을 도시한 그래프이다.24 is a W-Si/CoFeB/MgO/Ta structure according to Example 2, in which the silicon composition of the tungsten-silicon alloy layer is 3.0 at%, after vacuum heat treatment at 500° C. for 1 hour, leader pod backscattering ( It is a graph showing the Si content in W using Rutherford Backscattering, 25 is a W-Si/CoFeB/MgO/Ta structure according to Example 2 in which the silicon composition of the tungsten-silicon alloy layer is 4.0 at% 500

After vacuum heat treatment for 1 hour in a graph showing the Si content in W using Rutherford Backscattering, FIG. 26 is a tungsten-silicon alloy layer in which the silicon composition is 7.4 at% Example 2 After vacuum annealing the W-Si/CoFeB/MgO/Ta structure at 500° C. for 1 hour according to - After vacuum heat treatment of the W-Si/CoFeB/MgO/Ta structure according to Example 2 in which the silicon composition of the silicon alloy layer was 9.1 at% at 500° C. for 1 hour, Rutherford Backscattering was performed. It is a graph showing the Si content in the used W.

24 to 27, it can be seen that the silicon composition of the tungsten-silicon alloy layer is 3.0 at%, 4.0 at%, 7.4 at%, and 9.1 at%.

28 is a schematic diagram showing a CoFeB/W-Si/CoFeB/MgO/Ta structure according to Example 3 having perpendicular magnetic anisotropy, and FIG. 29 is a vacuum heat treatment at 500° C. for 1 hour, in Example 3 A graph showing a hysteresis curve when a magnetic field is applied to the CoFeB/W-Si/CoFeB/MgO/Ta structure according to the out-of-plane and in-plane directions of the thin film 30 to 32 are graphs showing hysteresis curves measuring magnetization reversal in no magnetic field applied with current.

Referring to FIG. 28 , it can be seen that magnetization easy directions exist for both directions (eg, x and y directions) in that residual magnetization remains when a magnetic field is applied to both the direction perpendicular to the plane of the thin film and the direction within the plane of the thin film. can

In addition, in the CoFeB/W-Si/CoFeB/MgO/Ta structure according to Example 3, by depositing a magnetic layer having an easy magnetization axis in an in-plane direction under the spin torque activation layer, magnetization inversion without a magnetic field is possible, and the lower magnetic layer and the spin torque The properties can be adjusted according to the thickness of the activation layer. Accordingly, it can be seen that the magnetic layer under the W-Si alloy layer has an easy magnetization axis in the in-plane direction and has an easy magnetization axis perpendicular to the back surface of the magnetic layer above the W-Si alloy layer according to the design.

30 and 31 show a situation in which magnetization reversal occurs due to spin orbital torque without applying an external magnetic field when the initial magnetization direction of the magnetic layer present under the W-Si alloy layer is in the -x or +x direction, respectively. As such, referring to FIGS. 30 and 31 , it can be seen that the initial magnetization of the lower magnetic layer determines the switching direction.

Referring to FIG. 32 , it can be seen that magnetization reversal occurs even at 0 Oe due to magnetization reversal due to spin orbital torque when the external magnetic field is changed from -200 Oe to +200 Oe. In addition, the switching direction is changed at +30 Oe because the magnetization direction of the lower magnetic layer is changed around 30 Oe. In this case, 30 Oe means the coercive force of the lower magnetic layer.

33 shows the silicon composition of the tungsten-silicon alloy layer of the W-Si/CoFeB/MgO/Ta structure according to Example 1-1 having perpendicular magnetic anisotropy by vacuum heat treatment at 500° C. for 1 hour (0.0 at% , 3.0 at%, 4.0 at%, 7.4 at%, 9.1 at%, 100 at%) is a graph showing the results of X-ray diffraction (X-ray Diffraction, XRD).

Data indicated by a bar graph in the lower part of FIG. 33 is standard data, and each standard data code is indicated in the graph.

Referring to FIG. 33, as a result of confirming the phase of the tungsten-silicon alloy layer using X-ray diffraction analysis, as the content of silicon (Si) increases, the beta-W (beta-W) phase is maintained up to 7.4 at% ( Trident peak around 40 degrees) From 9.1 at%, it changes to alpha-W (alpha-W) phase, which means that silicon (Si) initially stabilizes the beta phase, but as the content of silicon (Si) increases, the beta phase changes. It can be seen that -W (beta-W) prevents phase formation.

34 shows the composition of the tungsten-silicon alloy layer of the tungsten-silicon alloy layer of the W-Si/CoFeB/MgO/Ta structure according to Example 2 having perpendicular magnetic anisotropy by vacuum heat treatment at 300° C. for 1 hour ( 0.0, 4.0, 9.1 at%) is an image showing the phase of the thin film using an in-plane transmission electron microscope (TEM), and FIG. 35 is a vacuum at 500° C. for 1 hour. By heat treatment, according to the composition (0.0, 4.0, 9.1 at%) of the tungsten-silicon alloy layer of the tungsten-silicon alloy layer of the W-Si/CoFeB/MgO/Ta structure according to Example 2 having perpendicular magnetic anisotropy It is an image showing the phase of the thin film using an in-plane transmission electron microscope (TEM).

34 and 35, the thickness of W-Si is 25 nm.

Referring to FIGS. 34 and 35 , when the thickness is 25 nm or the heat treatment temperature is 300 degrees or more, it can be seen that tungsten (W) prefers an alpha phase.

In addition, when the content of silicon (Si), which is the first image in FIGS. 34 and 35, is 0 at%, it can be seen that tungsten (W) is present in an alpha phase, and the content of silicon (Si) is As it is increased to 4.0 at%, it can be seen that a beta-W (beta-W) phase appears even though it is a 25 nm thick thin film. W) It can be seen that phase separation occurs by looking at the phase change.

As described above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited to the above embodiments, and various modifications and variations from these descriptions are provided by those skilled in the art to which the present invention pertains. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the following claims as well as the claims and equivalents.

110: substrate 120: spin torque active layer
121: first direction 122: second direction
130: free layer 140: tunnel barrier
150: fixed bed 160: fixed bed

Claims (19)

a spin-orbit active layer formed on the substrate;
a free layer formed on the spin torque active layer;
a tunnel barrier layer formed on the free layer; and
a pinned layer formed on the tunnel barrier layer;
including,
The spin-torque active layer includes a WX alloy (wherein W is tungsten, and wherein X includes at least one of a group 4 semiconductor and a group 3-5 semiconductor). SOT) based magnetic tunnel junction.
According to claim 1,
The spin orbit torque-based magnetic tunnel junction, characterized in that the spin torque active layer is an electrode providing an in-plane current in contact with the free layer.
According to claim 1,
Spin orbit torque-based magnetic tunnel junction, characterized in that the switching current is reduced as the composition content of X included in the WX alloy increases.
According to claim 1,
A spin orbit torque-based magnetic tunnel junction, characterized in that the composition content of X included in the WX alloy is 0.1 at% to 10.6 at%.
According to claim 1,
The spin orbit torque-based magnetic tunnel junction is a spin orbit torque-based magnetic tunnel junction, characterized in that the switching current decreases as the heat treatment temperature at which the perpendicular magnetic anisotropy is expressed increases.
6. The method of claim 5,
A spin orbit torque-based magnetic tunnel junction, characterized in that the heat treatment temperature at which the perpendicular magnetic anisotropy is expressed is 300 °C to 500 °C.
7. The method of claim 6,
Spin orbit torque-based magnetic tunnel junction, characterized in that the composition content of X included in the WX alloy is controlled according to the heat treatment temperature at which the perpendicular magnetic anisotropy is expressed.
According to claim 1,
The spin orbit torque-based magnetic tunnel junction, characterized in that the spin torque active layer, the free layer, the tunnel barrier layer and the pinned layer have a cross shape in plan view.
According to claim 1,
The spin torque active layer has a cross shape when viewed in a plan view,
The spin orbit torque-based magnetic tunnel junction, wherein the free layer, the tunnel barrier layer, and the pinned layer are disposed in an island shape at the center of the cross-shaped spin torque active layer.
According to claim 1,
The spin orbit torque based magnetic tunnel junction, characterized in that the substrate includes a natural oxide layer on a surface in contact with the spin torque active layer.
According to claim 1,
The spin orbit torque-based magnetic tunnel junction, characterized in that the spin torque active layer further comprises a buffer layer at the bottom.
According to claim 1,
The spin orbit torque-based magnetic tunnel junction further comprises a capping layer on the pinned layer.
forming a spin torque active layer on a substrate;
forming a free layer on the spin torque active layer;
forming a tunnel barrier layer on the free layer;
forming a pinned layer formed on the tunnel barrier layer; and
performing heat treatment to express perpendicular magnetic anisotropy to the free layer and the pinned layer;
including,
The step of forming a spin torque active layer on the substrate,
A WX alloy thin film on the substrate disposed in the vacuum chamber by sputtering a W target and an X target simultaneously in a vacuum chamber (where W is tungsten, and X is at least one of a group 4 semiconductor and a group 3-5 semiconductor) A method of manufacturing a spin orbit torque-based magnetic tunnel junction, characterized in that it forms.
14. The method of claim 13,
A method of manufacturing a spin orbit torque-based magnetic tunnel junction, characterized in that the composition of the WX alloy thin film is adjusted according to the power of the W target and the X target.
14. The method of claim 13,
A method of manufacturing a spin orbit torque-based magnetic tunnel junction, characterized in that the composition content of X included in the WX alloy thin film is 0.1 at% to 10.6 at%.
14. The method of claim 13,
A method of manufacturing a spin orbit torque-based magnetic tunnel junction, characterized in that the switching current is reduced as the heat treatment temperature increases.
14. The method of claim 13,
The method of manufacturing a spin orbit torque-based magnetic tunnel junction, characterized in that the heat treatment temperature is 300 °C to 500 °C.
18. The method of claim 17,
The method of manufacturing a spin orbit torque-based magnetic tunnel junction, characterized in that the composition content of X included in the WX alloy is adjusted according to the heat treatment temperature.
14. The method of claim 13,
The step of forming a spin torque active layer on the substrate,
The method of manufacturing a spin orbit torque-based magnetic tunnel junction, characterized in that it further comprises the step of patterning the WX alloy thin film in a cross shape.

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