Magnetic memory device

Abstract

A magnetic memory device includes a conductive line extending in a first direction, a magnetic track line provided on the conductive line and extending in the first direction, and a non-magnetic line provided on the magnetic track line and extending in the first direction. The magnetic track line includes a lower magnetic layer and an upper magnetic layer stacked on the conductive line, an exchange coupling layer between the lower magnetic layer and the upper magnetic layer, and a spacer layer between the exchange coupling layer and the upper magnetic layer. The exchange coupling layer is in contact with a bottom surface of the spacer layer, and the lower magnetic layer and the upper magnetic layer are antiferromagnetic coupled to each other through the exchange coupling layer.

Description

Technical Field

[0001] The present disclosure relates to a magnetic storage device, and more particularly, to a magnetic storage device that utilizes the movement of magnetic domain walls. Background Art

[0002] Due to the increasing demand for electronic devices with high speed and / or low power consumption, storage devices embedded in electronic devices can benefit from fast operation speed and / or low operation voltage. Summary of the Invention

[0003] Magnetic storage devices are being developed to meet various requirements, such as reduced latency and / or non-volatility.

[0004] A magnetic storage device has a magnetic track line including a plurality of magnetic domains, and the moving direction of the magnetic domains in the magnetic track line changes according to the direction of an electric current. A read / write device is provided near the magnetic track line to perform operations of reading data from and writing data into the magnetic domains. For example, a magnetic tunnel junction can be used as the read / write device. Various studies have been conducted to reduce the current required to move the magnetic domains and to improve the tunneling magnetoresistance characteristics of the magnetic tunnel junction.

[0005] The present disclosure describes a magnetic storage device including a magnetic track line having a high magnetic domain movement efficiency.

[0006] The present disclosure describes a magnetic storage device in which a magnetic tunnel junction having improved tunneling magnetoresistance characteristics is used as a read device.

[0007] An exemplary magnetic storage device may include a conductive wire extending in a first direction, a magnetic track line provided on the conductive wire and extending in the first direction, and a non-magnetic wire provided on the magnetic track line and extending in the first direction. The magnetic track line may include a lower magnetic layer and an upper magnetic layer stacked on the conductive wire, an exchange coupling layer between the lower magnetic layer and the upper magnetic layer, and a spacer layer between the exchange coupling layer and the upper magnetic layer. The exchange coupling layer may be in contact with the bottom surface of the spacer layer, and the lower magnetic layer and the upper magnetic layer may be antiferromagnetically coupled to each other through the exchange coupling layer.

[0008] An exemplary magnetic storage device may include a conductive wire extending in a first direction, a magnetic track line provided on the top surface of the conductive wire and extending in the first direction, and a reference magnetic pattern on the magnetic track line. The magnetic track line may include a lower magnetic layer and an upper magnetic layer stacked on the conductive wire, an exchange coupling layer between the lower magnetic layer and the upper magnetic layer, and a spacer layer between the exchange coupling layer and the upper magnetic layer. The bottom surface of the spacer layer may be in contact with the exchange coupling layer, and the top surface of the spacer layer may be in contact with the upper magnetic layer. The lower magnetic layer and the upper magnetic layer may be antiferromagnetically coupled to each other through the exchange coupling layer. Brief Description of the Drawings

[0009] Figure 1is a perspective view schematically showing an exemplary magnetic storage device.

[0010] Figure 2 is a cross-sectional view taken along Figure 1 line I-I'.

[0011] Figure 3A , Figure 3B , Figure 4A and Figure 4B are cross-sectional views showing an exemplary method of manufacturing a magnetic storage device, Figure 3A and Figure 4A are cross-sectional views corresponding to Figure 1 line I-I', Figure 3B and Figure 4B are cross-sectional views corresponding to Figure 1 line II-II'.

[0012] Figure 5A and Figure 5B are cross-sectional views taken along Figure 1 line I-I' to show the magnetic storage device.

[0013] Figure 6A is a plan view showing an exemplary magnetic storage device, Figure 6B is a cross-sectional view taken along Figure 6A line III-III'.

[0014] Figure 7A is a plan view showing an exemplary magnetic storage device, Figure 7B is a cross-sectional view taken along Figure 7A line III-III'.

[0015] Figure 8A is a plan view showing an exemplary magnetic storage device, Figure 8B is a cross-sectional view taken along Figure 8A line III-III'.

[0016] Figure 9A is a plan view showing an exemplary magnetic storage device, Figure 9B is a cross-sectional view taken along Figure 9A line III-III'. Detailed Description

[0017] Exemplary implementations will now be described more fully with reference to the accompanying drawings, in which the exemplary implementations are shown.

[0018] Figure 1 is a perspective view schematically showing a magnetic storage device. Figure 2 is a cross-sectional view taken along Figure 1 line I-I'.

[0019] Referring toFigure 1 and Figure 2 , the magnetic storage device may include a conductive wire CL, a magnetic track line MTL on the conductive wire CL, a non-magnetic wire 150 on the magnetic track line MTL, and a reading device 200 on the non-magnetic wire 150. The conductive wire CL may extend in a first direction D1 parallel to a top surface CL_U of the conductive wire CL. The magnetic track line MTL and the non-magnetic wire 150 may be sequentially stacked on the top surface CL_U of the conductive wire CL in a second direction D2 perpendicular to the top surface CL_U of the conductive wire CL. The magnetic track line MTL may be interposed between the conductive wire CL and the non-magnetic wire 150. The magnetic track line MTL and the non-magnetic wire 150 may extend in the first direction D1. Each of the conductive wire CL, the magnetic track line MTL, and the non-magnetic wire 150 may have a width in a third direction D3 parallel to the top surface CL_U of the conductive wire CL and not parallel to the first direction D1, and each of the conductive wire CL, the magnetic track line MTL, and the non-magnetic wire 150 may be a linear pattern having a length in the first direction D1 greater than its width in the third direction D3. The third direction D3 may be perpendicular to the first direction D1. The reading device 200 may be disposed adjacent to a portion of the non-magnetic wire 150.

[0020] The conductive wire CL may be configured to generate a spin-orbit torque by a current Ic flowing therethrough. The current Ic may be an in-plane current that flows through the conductive wire CL in the first direction D1 or in a direction opposite to the first direction D1. The conductive wire CL may include a material that generates a spin Hall effect or a Rashba effect when there is a current Ic flowing through the conductive wire CL. The conductive wire CL may include a heavy metal having an atomic number of 30 or higher, and may include at least one of iridium (Ir), ruthenium (Ru), tantalum (Ta), platinum (Pt), palladium (Pd), bismuth (Bi), hafnium (Hf), titanium (Ti), tungsten (W), and alloys thereof. In one implementation, the conductive wire CL may include a topological insulator including Bi, Se, Te, and / or Sb.

[0021] The magnetic track line MTL may include a lower magnetic layer 110, an exchange coupling layer 120, a spacer layer 130, and an upper magnetic layer 140 that are sequentially stacked on a conductive line CL. The lower magnetic layer 110, the exchange coupling layer 120, the spacer layer 130, and the upper magnetic layer 140 may be sequentially stacked on the top surface CL_U of the conductive line CL in a second direction D2. The lower magnetic layer 110 may be interposed between the conductive line CL and the exchange coupling layer 120, and the exchange coupling layer 120 may be interposed between the lower magnetic layer 110 and the spacer layer 130. The spacer layer 130 may be interposed between the exchange coupling layer 120 and the upper magnetic layer 140. Each of the lower magnetic layer 110, the exchange coupling layer 120, the spacer layer 130, and the upper magnetic layer 140 may be a linear pattern extending in a first direction D1. Each of the conductive line CL and the magnetic track line MTL may be a linear pattern extending in the first direction D1, but the inventive concept is not limited to this example. For example, the conductive line CL and the magnetic track line MTL may be U-shaped line patterns.

[0022] The lower magnetic layer 110 may include a plurality of lower magnetic domains DM1 arranged in a first direction D1 and lower magnetic domain walls DW1 provided between the lower magnetic domains DM1. Each lower magnetic domain DM1 may be a region formed in the lower magnetic layer 110 and having magnetic moments with the same or aligned directions, and each lower magnetic domain wall DW1 may be a boundary formed between the lower magnetic domains DM1 where the direction of the magnetic moment changes. The lower magnetic domains DM1 and the lower magnetic domain walls DW1 may be alternately arranged in the first direction D1. The bottom surface of the lower magnetic layer 110 may be in contact with the conductive line CL, and the top surface of the lower magnetic layer 110 may be in contact with the exchange coupling layer 120.

[0023] In an example, the lower magnetic layer 110 may have perpendicular magnetic anisotropy (PMA). Each lower magnetic domain DM1 may have a magnetization direction MDf1 that is perpendicular to the interface between the lower magnetic layer 110 and the exchange coupling layer 120. The magnetization direction MDf1 of each lower magnetic domain DM1 may be perpendicular to the top surface CL_U of the conductive line CL. A pair of adjacent lower magnetic domains DM1 may have magnetization directions MDf1 that are opposite to each other. Each lower magnetic domain wall DW1 may define a boundary between a pair of lower magnetic domains DM1 having opposite magnetization directions MDf1.

[0024] The lower magnetic layer 110 may have a (111) texture of a face-centered cubic (FCC) structure or a (001) texture of a hexagonal close-packed (HCP) structure. In this case, the FCC (111) crystal plane or the HCP (001) crystal plane of the lower magnetic layer 110 may be parallel to the interface between the lower magnetic layer 110 and the exchange coupling layer 120. The lower magnetic layer 110 may have an FCC (111) crystal plane or an HCP (001) crystal plane at the interface between the lower magnetic layer 110 and the exchange coupling layer 120. The conductive line CL may accelerate the growth of the FCC (111) crystal plane or the HCP (001) crystal plane of the lower magnetic layer 110. The lower magnetic layer 110 may include at least one of cobalt (Co), iron (Fe), and nickel (Ni), and in one implementation, it may further include at least one of palladium (Pd), platinum (Pt), gadolinium (Gd), and terbium (Tb). In one implementation, the lower magnetic layer 110 may include cobalt or a cobalt alloy, where the cobalt alloy may include an alloy containing at least one of iron (Fe), nickel (Ni), palladium (Pd), platinum (Pt), gadolinium (Gd), and terbium (Tb) and cobalt.

[0025] The exchange coupling layer 120 may be configured to antiferromagnetically couple the lower magnetic layer 110 to the upper magnetic layer 140. The exchange coupling layer 120 may include a first non-magnetic metal (e.g., ruthenium (Ru), iridium (Ir), rhodium (Rh), tungsten (W), tantalum (Ta), or an alloy thereof). The bottom surface of the exchange coupling layer 120 may be in contact with the lower magnetic layer 110, and the top surface of the exchange coupling layer 120 may be in contact with the spacer layer 130.

[0026] The spacer layer 130 may include a second non-magnetic metal (e.g., tungsten (W), tantalum (Ta), molybdenum (Mo), niobium (Nb), rhenium (Re), or an alloy thereof). The spacer layer 130 may further include a magnetic element. In one implementation, the spacer layer 130 may include an alloy containing at least one of CoFeB, Co, Fe, and CoFe and the second non-magnetic metal. The spacer layer 130 may further include boron (B). In the case of performing a heat treatment process on the magnetic track line MTL, the spacer layer 130 may absorb boron (B) atoms diffused in the magnetic track line MTL.

[0027] The bottom surface of the spacer layer 130 may be in contact with the exchange coupling layer 120, and the top surface of the spacer layer 130 may be in contact with the upper magnetic layer 140. The spacer layer 130 may block the FCC (111) texture or HCP (001) texture of the underlying layers (e.g., the lower magnetic layer 110 and the exchange coupling layer 120), and may accelerate the growth of the BCC (001) crystal plane of the upper magnetic layer 140. The spacer layer 130 may be used to adjust the strength of the antiferromagnetic coupling between the lower magnetic layer 110 and the upper magnetic layer 140. As an example, when the thickness of the spacer layer 130 increases in the second direction D2, the strength of the antiferromagnetic coupling between the lower magnetic layer 110 and the upper magnetic layer 140 may decrease, and when the thickness of the spacer layer 130 decreases in the second direction D2, the strength of the antiferromagnetic coupling between the lower magnetic layer 110 and the upper magnetic layer 140 may increase.

[0028] The upper magnetic layer 140 may include a plurality of upper magnetic domains DM2 arranged in the first direction D1 and upper magnetic domain walls DW2 provided between the upper magnetic domains DM2. Each upper magnetic domain DM2 may be a region of magnetic moments formed in the upper magnetic layer 140 and having the same or aligned directions, and each upper magnetic domain wall DW2 may be a boundary formed between the upper magnetic domains DM2 where the direction of the magnetic moment changes. The upper magnetic domains DM2 and the upper magnetic domain walls DW2 may be alternately arranged in the first direction D1. The upper magnetic domains DM2 may vertically overlap the lower magnetic domains DM1 in the second direction D2, respectively. The bottom surface of the upper magnetic layer 140 may be in contact with the spacer layer 130, and the top surface of the upper magnetic layer 140 may be in contact with the non-magnetic line 150.

[0029] The upper magnetic layer 140 may have perpendicular magnetic anisotropy (PMA). Each upper magnetic domain DM2 may have a magnetization direction MDf2 that is perpendicular to the interface between the upper magnetic layer 140 and the non-magnetic line 150. The magnetization direction MDf2 of each upper magnetic domain DM2 may be perpendicular to the top surface CL_U of the conductive line CL. A pair of upper magnetic domains DM2 that are closest to each other may have opposite magnetization directions MDf2. Each upper magnetic domain wall DW2 may define the boundary between a pair of upper magnetic domains DM2 having opposite magnetization directions MDf2.

[0030] The upper magnetic domains DM2 may vertically overlap the lower magnetic domains DM1 in the second direction D2, respectively, and the upper magnetic domains DM2 and the lower magnetic domains DM1 may be antiferromagnetically coupled to each other through the exchange coupling layer 120. The magnetization direction MDf2 of each upper magnetic domain DM2 may be antiparallel to the magnetization direction MDf1 of the corresponding one in the lower magnetic domain DM1.

[0031] The upper magnetic layer 140 may have a (001) texture of a body-centered cubic (BCC) structure. The upper magnetic layer 140 may have a BCC lattice structure and may have a BCC (001) texture. In this case, the BCC (001) crystal plane of the upper magnetic layer 140 may be parallel to the interface between the upper magnetic layer 140 and the non-magnetic line 150. The upper magnetic layer 140 may have a BCC (001) crystal plane at the interface between the upper magnetic layer 140 and the non-magnetic line 150. The spacer layer 130 may accelerate the growth of the BCC (001) crystal plane of the upper magnetic layer 140. The upper magnetic layer 140 may include at least one of cobalt (Co), iron (Fe), and nickel (Ni) and may also include boron (B). In one implementation, the upper magnetic layer 140 may include CoFeB or FeB.

[0032] The non-magnetic line 150 may include a metal oxide material. In one implementation, the non-magnetic line 150 may include at least one of magnesium oxide, titanium oxide, aluminum oxide, magnesium aluminum oxide, magnesium gallium oxide, magnesium zinc oxide, and magnesium boron oxide.

[0033] The non-magnetic line 150 may have a (001) texture of an NaCl structure. The non-magnetic line 150 may have an NaCl lattice structure, and the (001) crystal plane of the non-magnetic line 150 may be parallel to the interface between the upper magnetic layer 140 and the non-magnetic line 150. The non-magnetic line 150 may have a (001) crystal plane at the interface between the upper magnetic layer 140 and the non-magnetic line 150. The (001) crystal plane of the upper magnetic layer 140 and the (001) crystal plane of the non-magnetic line 150 may be in contact with each other and may form an interface therebetween. The non-magnetic line 150 may be referred to as a tunnel barrier line.

[0034] The read device 200 may include a reference magnetic pattern 210 on the non-magnetic line 150 and an electrode pattern 220 on the reference magnetic pattern 210. The reference magnetic pattern 210 may be disposed between the non-magnetic line 150 and the electrode pattern 220. The read device 200 may overlap perpendicularly (e.g., in the second direction D2) with a corresponding one in the upper magnetic domain DM2 and a corresponding one in the lower magnetic domain DM1.

[0035] In one example, the reference magnetic pattern 210 may have perpendicular magnetic anisotropy (PMA). The reference magnetic pattern 210 may have a magnetization direction MDp that is perpendicular to the interface between the reference magnetic pattern 210 and the non-magnetic line 150, and the magnetization direction MDp of the reference magnetic pattern 210 may be fixed to a specific direction. The reference magnetic pattern 210 may include at least one of cobalt (Co), iron (Fe), and nickel (Ni), and may also include at least one of non-magnetic materials (e.g., boron (B), zinc (Zn), aluminum (Al), titanium (Ti), ruthenium (Ru), tantalum (Ta), silicon (Si), silver (Ag), gold (Au), copper (Cu), carbon (C), and nitrogen (N)). The reference magnetic pattern 210 may include at least one of the following: i) perpendicular magnetic materials (e.g., CoFeTb, CoFeGd, and CoFeDy), ii) perpendicular magnetic materials having an L10 structure, iii) CoPt-based materials having a hexagonal close-packed structure, or iv) perpendicular magnetic structures. The perpendicular magnetic materials having an L10 structure may include at least one of L10 FePt, L10 FePd, L10 CoPd, and L10 CoPt. The perpendicular magnetic structure may include alternately and repeatedly stacked magnetic layers and non-magnetic layers. For example, the perpendicular magnetic structure may include at least one of (Co / Pt)n, (CoFe / Pt)n, (CoFe / Pd)n, (Co / Pd)n, (Co / Ni)n, (CoNi / Pt)n, (CoCr / Pt)n, and (CoCr / Pd)n, where n is the number of pairs of stacked layers. The reference magnetic pattern 210 may be formed of at least one of CoFeB and Co-based Heusler alloys, or may include at least one of CoFeB and Co-based Heusler alloys.

[0036] The reference magnetic pattern 210 may overlap perpendicularly (e.g., in the second direction D2) with a corresponding one in the upper magnetic domain DM2 and a corresponding one in the lower magnetic domain DM1. The reference magnetic pattern 210, the corresponding upper magnetic domain DM2, and the corresponding lower magnetic domain DM1 that overlap perpendicularly with each other may form a magnetic tunnel junction.

[0037] The electrode pattern 220 may include a conductive material and may include at least one of a metal material (e.g., copper, tungsten, or aluminum) and / or a metal nitride material (e.g., tantalum nitride, titanium nitride, or tungsten nitride).

[0038] In the case where a current Ic flows through the conductive wire CL in a first direction D1 or in a direction opposite to the first direction D1, the lower magnetic domain wall DW1 in the lower magnetic layer 110 can move in the first direction D1. The movement of the lower magnetic domain wall DW1 can be caused by a spin-orbit torque and a Dzyaloshinskii-Moriya interaction (DMI) that occurs at the interface between the conductive wire CL and the lower magnetic layer 110. The moving direction of the lower magnetic domain wall DW1 can depend on the chirality of the lower magnetic domain wall DW1. Since the lower magnetic domain wall DW1 in the lower magnetic layer 110 moves in the first direction D1, the upper magnetic domain wall DW2 in the upper magnetic layer 140 can also move in the first direction D1. The movement of the upper magnetic domain wall DW2 can be caused by an antiferromagnetic coupling between the lower magnetic layer 110 and the upper magnetic layer 140.

[0039] Since the lower magnetic layer 110 has an FCC (111) texture or an HCP (001) texture, the strength of the antiferromagnetic coupling between the lower magnetic layer 110 and the upper magnetic layer 140 can be increased. Accordingly, the lower magnetic domain wall DW1 and the upper magnetic domain wall DW2 in the magnetic track line MTL can move with improved efficiency. This means that the current Ic required to move the lower magnetic domain wall DW1 and the upper magnetic domain wall DW2 in the magnetic track line MTL can be reduced.

[0040] During a read operation, a read current Iread can flow through a magnetic tunnel junction including a reference magnetic pattern 210, a corresponding upper magnetic domain DM2, and a corresponding lower magnetic domain DM1 that overlap perpendicularly to each other. The resistance state of the magnetic tunnel junction can be detected by the read current Iread. For example, by measuring the read current Iread, it can be determined whether the magnetic tunnel junction is in a high-resistance state or a low-resistance state. The resistance state of the magnetic tunnel junction can be used to determine whether the data stored in the magnetic track line MTL is 0 or 1.

[0041] Since the upper magnetic layer 140 has a BCC (001) texture, the magnetic anisotropy of the upper magnetic layer 140 caused by the coupling between the upper magnetic layer 140 and the non-magnetic wire 150 can be improved. Accordingly, the tunneling magnetoresistance ratio (TMR) of the magnetic tunnel junction can be increased, which enables the read device 200 to stably perform a read operation.

[0042] In one example, the lower magnetic layer 110 and the upper magnetic layer 140 can be antiferromagnetically coupled to each other through the exchange coupling layer 120. Since the lower magnetic layer 110 has an FCC (111) texture or an HCP (001) texture, the strength of the antiferromagnetic coupling between the lower magnetic layer 110 and the upper magnetic layer 140 can be increased, which enables the lower magnetic domain wall DW1 and the upper magnetic domain wall DW2 in the magnetic track line MTL to be moved more effectively. The spacer layer 130 can be interposed between the exchange coupling layer 120 and the upper magnetic layer 140. The spacer layer 130 can block the FCC (111) texture or the HCP (001) texture of the lower magnetic layer 110 and can accelerate the crystal growth of the upper magnetic layer 140 having a BCC (001) texture. Since the upper magnetic layer 140 has a BCC (001) texture, the tunneling magnetoresistance ratio of the magnetic tunnel junction can be increased, and thus, the reading operation of the reading device 200 can be performed in a more stable manner.

[0043] Figure 3A , Figure 3B , Figure 4A and Figure 4B are cross-sectional views showing a method of manufacturing an exemplary magnetic storage device. Figure 3A and Figure 4A are cross-sectional views corresponding to the line I-I' of Figure 1 , Figure 3B and Figure 4B are cross-sectional views corresponding to the line II-II' of Figure 1 . For the sake of brevity, elements identical to those in the magnetic storage device described with reference to Figure 1 and Figure 2 can be identified by the same reference numerals without repeated overlapping description.

[0044] Referring to Figure 3A and Figure 3B , an initial lower magnetic layer 110L, an initial exchange coupling layer 120L, an initial spacer layer 130L, an initial upper magnetic layer 140L, and a non-magnetic thin film 150L can be sequentially stacked on the conductive thin film CLa. The conductive thin film CLa, the initial lower magnetic layer 110L, the initial exchange coupling layer 120L, the initial spacer layer 130L, the initial upper magnetic layer 140L, and the non-magnetic thin film 150L can be formed by a chemical vapor deposition process or a physical vapor deposition process (such as a sputtering deposition process).

[0045] The reference magnetic pattern 210 and the electrode pattern 220 may be formed on the non-magnetic thin film 150L. In one implementation, the formation of the reference magnetic pattern 210 and the electrode pattern 220 may include: sequentially depositing a reference magnetic layer and an electrode layer on the non-magnetic thin film 150L; forming a first mask pattern M1 on the electrode layer to define the planar shape of the reference magnetic pattern 210; and performing a first etching process IB1 using the first mask pattern M1 as an etching mask to etch the reference magnetic layer and the electrode layer. The reference magnetic layer and the electrode layer may be formed by a chemical vapor deposition process or a physical vapor deposition method (e.g., a sputter deposition process). In one implementation, the first mask pattern M1 may be a photoresist pattern or a hard mask pattern. The first etching process IB1 may be, for example, an ion beam etching process using inert ions (e.g., argon (Ar)). In one implementation, a metal element in the non-magnetic thin film 150L may be used as an element for generating an endpoint detection (EPD) signal in the first etching process IB1. The first etching process IB1 may be performed to expose the non-magnetic thin film 150L, and the initial upper magnetic layer 140L may not be exposed during the first etching process IB1.

[0046] In the case of performing the first etching process IB1 using the EPD signal generated when a metal element in the non-magnetic thin film 150L is detected, the reference magnetic layer and the electrode layer can be sufficiently etched and the non-magnetic thin film 150L can be easily exposed. Accordingly, unetched portions or residues of the reference magnetic layer and the electrode layer can be prevented from remaining on the non-magnetic thin film 150L. In addition, the initial upper magnetic layer 140L may not be exposed to the outside during the first etching process IB1, and thus, the initial upper magnetic layer 140L can be prevented from being damaged by the first etching process IB1.

[0047] Referring to Figure 4A and Figure 4B , after the reference magnetic pattern 210 and the electrode pattern 220 are formed, the first mask pattern M1 may be removed. In one implementation, the first mask pattern M1 may be removed using an ashing and / or stripping process.

[0048] A second mask pattern M2 may be formed on the non-magnetic thin film 150L to cover the reference magnetic pattern 210 and the electrode pattern 220. The second mask pattern M2 may have a linear shape extending in a first direction D1. In one implementation, the second mask pattern M2 may be a photoresist pattern or a hard mask pattern.

[0049] The non-magnetic thin film 150L, the initial upper magnetic layer 140L, the initial spacer layer 130L, the initial exchange coupling layer 120L, the initial lower magnetic layer 110L, and the conductive thin film CLa can be sequentially etched by a second etching process IB2 using the second mask pattern M2 as an etching mask. Thus, the conductive line CL, the lower magnetic layer 110, the exchange coupling layer 120, the spacer layer 130, the upper magnetic layer 140, and the non-magnetic line 150 can be formed. The second etching process IB2 can be an ion beam etching process, and in one implementation, it can be an ion beam etching process using inert ions (e.g., argon (Ar)).

[0050] Each of the conductive line CL, the lower magnetic layer 110, the exchange coupling layer 120, the spacer layer 130, the upper magnetic layer 140, and the non-magnetic line 150 can be a linear structure extending in the first direction D1. The lower magnetic layer 110, the exchange coupling layer 120, the spacer layer 130, and the upper magnetic layer 140 can form a magnetic track line MTL. The second mask pattern M2 can be removed after forming the conductive line CL, the magnetic track line MTL, and the non-magnetic line 150. In one implementation, the second mask pattern M2 can be removed by an ashing and / or stripping process.

[0051] Figure 5A and Figure 5B is a cross-sectional view taken along the line I-I' to show a cross-section of an exemplary magnetic storage device. For simplicity, the elements different from those in the magnetic storage device described with reference to Figure 1 will be mainly described below. Figure 1 and Figure 2

[0052] Referring to Figure 5A and Figure 5B , the read device 200 can include a reference magnetic pattern 210 on the non-magnetic line 150 and an electrode pattern 220 on the reference magnetic pattern 210. The reference magnetic pattern 210 can be disposed between the non-magnetic line 150 and the electrode pattern 220.

[0053] Referring to Figure 5A , the reference magnetic pattern 210 can include a first pinned pattern 211 between the non-magnetic line 150 and the electrode pattern 220, a second pinned pattern 215 between the non-magnetic line 150 and the first pinned pattern 211, and a first non-magnetic pattern 213 between the first pinned pattern 211 and the second pinned pattern 215.

[0054] ​Each of the first pinned pattern 211 and the second pinned pattern 215 may have perpendicular magnetic anisotropy (PMA). The first pinned pattern 211 may have a magnetization direction MDp1 perpendicular to the interface between the non-magnetic line 150 and the second pinned pattern 215, and the magnetization direction MDp1 of the first pinned pattern 211 may be fixed to a specific direction. The second pinned pattern 215 may have a magnetization direction MDp2 perpendicular to the interface between the non-magnetic line 150 and the second pinned pattern 215, and the magnetization direction MDp2 of the second pinned pattern 215 may be fixed to be antiparallel to the magnetization direction MDp1 of the first pinned pattern 211. The second pinned pattern 215 may be antiferromagnetically coupled to the first pinned pattern 211 through the first non-magnetic pattern 213. That is, the first non-magnetic pattern 213 may be configured to antiferromagnetically couple the first pinned pattern 211 and the second pinned pattern 215 to each other.

[0055] Each of the first pinned pattern 211 and the second pinned pattern 215 may include at least one of cobalt (Co), iron (Fe), and nickel (Ni), and may also include at least one of non-magnetic materials (e.g., boron (B), zinc (Zn), aluminum (Al), titanium (Ti), ruthenium (Ru), tantalum (Ta), silicon (Si), silver (Ag), gold (Au), copper (Cu), carbon (C), and nitrogen (N)). Each of the first pinned pattern 211 and the second pinned pattern 215 may include at least one of the following: i) perpendicular magnetic materials (e.g., CoFeTb, CoFeGd, and CoFeDy), ii) perpendicular magnetic materials having an L10 structure, iii) CoPt-based materials having a hexagonal close-packed structure, or iv) perpendicular magnetic structures. The perpendicular magnetic material having an L10 structure may include at least one of L10 FePt, L10FePd, L10 CoPd, and L10 CoPt. The perpendicular magnetic structure may include alternately and repeatedly stacked magnetic layers and non-magnetic layers. For example, the perpendicular magnetic structure may include at least one of (Co / Pt)n, (CoFe / Pt)n, (CoFe / Pd)n, (Co / Pd)n, (Co / Ni)n, (CoNi / Pt)n, (CoCr / Pt)n, and (CoCr / Pd)n, where n is the number of pairs of stacked layers. Each of the first pinned pattern 211 and the second pinned pattern 215 may be formed of at least one of CoFeB and Co-based Heusler alloys, or may include at least one of CoFeB and Co-based Heusler alloys.

[0056] The first non-magnetic pattern 213 may include a non-magnetic metal material (e.g., ruthenium (Ru), iridium (Ir), rhodium (Rh), tungsten (W), tantalum (Ta), or an alloy thereof).

[0057] Refer toFigure 5B In addition, the reference magnetic pattern 210 may further include a third pinned pattern 219 between the non-magnetic line 150 and the second pinned pattern 215, and a second non-magnetic pattern 217 between the second pinned pattern 215 and the third pinned pattern 219.

[0058] The third pinned pattern 219 may have perpendicular magnetic anisotropy (PMA). The third pinned pattern 219 may have a magnetization direction MDp3 perpendicular to the interface between the non-magnetic line 150 and the third pinned pattern 219, and the magnetization direction MDp3 of the third pinned pattern 219 may be fixed to be parallel to the magnetization direction MDp2 of the second pinned pattern 215. The third pinned pattern 219 may be ferromagnetically coupled to the second pinned pattern 215 through the second non-magnetic pattern 217. The second non-magnetic pattern 217 may be configured to ferromagnetically couple the second pinned pattern 215 to the third pinned pattern 219.

[0059] The third pinned pattern 219 may include at least one of cobalt (Co), iron (Fe), and nickel (Ni), and may further include at least one of non-magnetic materials (e.g., boron (B), zinc (Zn), aluminum (Al), titanium (Ti), ruthenium (Ru), tantalum (Ta), silicon (Si), silver (Ag), gold (Au), copper (Cu), carbon (C), and nitrogen (N)). In one implementation, the third pinned pattern 219 may include CoFeB. The second non-magnetic pattern 217 may include a non-magnetic metal material (e.g., ruthenium (Ru), iridium (Ir), rhodium (Rh), tungsten (W), tantalum (Ta), or an alloy thereof).

[0060] Except for the aforementioned differences, the magnetic storage device according to this implementation may be substantially the same as the magnetic storage device described with reference to Figure 1 and Figure 2 Description of the magnetic storage device.

[0061] Figure 6A is a plan view showing an exemplary magnetic storage device, Figure 6B is a cross-sectional view taken along the line III-III' of Figure 6A For simplicity, the elements different from those in the magnetic storage device described with reference to Figure 1 and Figure 2 will be mainly described below.

[0062] Refer to Figure 6A and Figure 6B, the magnetic track line MTL may include a line portion LP extending in a first direction D1 and two end portions EP respectively connected to opposite ends of the line portion LP. The two end portions EP may be spaced apart from each other in the first direction D1, with the line portion LP interposed therebetween. The line portion LP may have a first width W1 in a third direction D3, and each end portion EP may have a second width W2 in the third direction D3. The second width W2 may be greater than the first width W1. The second width W2 of each end portion EP may increase as the distance from the line portion LP (e.g., in the first direction D1 or its opposite direction) increases.

[0063] The lower magnetic layer 110 of the line portion LP may include a pair of lower magnetic domains DM1 arranged in the first direction D1 and a lower magnetic domain wall DW1 formed between the pair of lower magnetic domains DM1. The pair of lower magnetic domains DM1 may have magnetization directions MDf1 opposite to each other. The upper magnetic layer 140 of the line portion LP may include a pair of upper magnetic domains DM2 arranged in the first direction D1 and an upper magnetic domain wall DW2 formed between the pair of upper magnetic domains DM2. The pair of upper magnetic domains DM2 may have magnetization directions MDf2 opposite to each other. The pair of upper magnetic domains DM2 may vertically overlap the pair of lower magnetic domains DM1 in a second direction D2, and the pair of upper magnetic domains DM2 and the pair of lower magnetic domains DM1 may be antiferromagnetically coupled to each other through an exchange coupling layer 120. The magnetization direction MDf2 of each upper magnetic domain DM2 may be antiparallel to the magnetization direction MDf1 of the corresponding one of the lower magnetic domains DM1.

[0064] The reading device 200 may be disposed on the line portion LP of the magnetic track line MTL. The reading device 200 may vertically overlap (e.g., in the second direction D2) a corresponding one of the upper magnetic domains DM2 and a corresponding one of the lower magnetic domains DM1 to form a magnetic tunnel junction. The reading device 200 may detect the resistance state of the magnetic tunnel junction, or may determine whether the magnetic tunnel junction is in a high-resistance state or a low-resistance state. The magnetic storage device according to the present implementation may be used as a single-bit storage device.

[0065] Figure 7A is a plan view showing an exemplary magnetic storage device, Figure 7B is along Figure 7A The cross-sectional view taken along the line III-III'. For simplicity, the elements different from those in the magnetic storage device described with reference to Figure 1 and Figure 2 will be mainly described below.

[0066] Referring to Figure 7A and Figure 7B, the magnetic track line MTL may include a line portion LP extending in a first direction D1 and two end portions EP respectively connected to opposite ends of the line portion LP. The two end portions EP may be spaced apart from each other in the first direction D1, and the line portion LP is interposed therebetween. The line portion LP may have a first width W1 in a third direction D3, and each end portion EP may have a second width W2 in the third direction D3. The second width W2 may be greater than the first width W1. The second width W2 of each end portion EP may increase as the distance from the line portion LP (e.g., in the first direction D1 or its opposite direction) increases.

[0067] The lower magnetic layer 110 of the line portion LP may include lower magnetic domains DM1 arranged in the first direction D1 and lower magnetic domain walls DW1 formed between the lower magnetic domains DM1. In one implementation, the number of the lower magnetic domains DM1 may be at least three. The lower magnetic domains DM1 and the lower magnetic domain walls DW1 may be alternately arranged in the first direction D1. A pair of the lower magnetic domains DM1 closest to each other may have opposite magnetization directions MDf1. Each lower magnetic domain wall DW1 may define a boundary between a pair of lower magnetic domains DM1 having opposite magnetization directions MDf1.

[0068] The upper magnetic layer 140 of the line portion LP may include upper magnetic domains DM2 arranged in the first direction D1 and upper magnetic domain walls DW2 located between the upper magnetic domains DM2. The number of the upper magnetic domains DM2 may be at least three. The upper magnetic domains DM2 and the upper magnetic domain walls DW2 may be alternately arranged in the first direction D1. A pair of the upper magnetic domains DM2 closest to each other may have opposite magnetization directions MDf2 with respect to each other. Each upper magnetic domain wall DW2 may define a boundary between a pair of upper magnetic domains DM2 having opposite magnetization directions MDf2. The upper magnetic domains DM2 may respectively overlap the lower magnetic domains DM1 perpendicularly in a second direction D2, and the upper magnetic domains DM2 and the lower magnetic domains DM1 may be antiferromagnetically coupled to each other through an exchange coupling layer 120. The magnetization direction MDf2 of each upper magnetic domain DM2 may be antiparallel to the magnetization direction MDf1 of a corresponding one of the lower magnetic domains DM1.

[0069] The reading device 200 may be disposed on the line portion LP of the magnetic track line MTL. The reading device 200 may overlap perpendicularly (e.g., in the second direction D2) with a corresponding one of the upper magnetic domains DM2 and a corresponding one of the lower magnetic domains DM1 to form a magnetic tunnel junction. The reading device 200 may detect the resistance state of the magnetic tunnel junction, or may determine whether the magnetic tunnel junction is in a high-resistance state or a low-resistance state. The magnetic storage device according to the present implementation may be used as a multi-bit storage device.

[0070] Figure 8A is a plan view showing an exemplary magnetic storage device, Figure 8B is along Figure 8ACross-sectional view taken along line III-III'. For simplicity, the following will mainly describe components different from those in the magnetic storage device described with reference to Figure 6A , Figure 6B , Figure 7A and Figure 7B .

[0071] With reference to Figure 8A and Figure 8B , the line portion LP of the magnetic track line MTL may have a first length L1 in a first direction D1, and the reading device 200 may have a second length L2 in the first direction D1. In this implementation, the second length L2 of the reading device 200 may be substantially equal to the first length L1 of the line portion LP. The reading device 200 may be a linear structure extending in the first direction D1. The reading device 200 may overlap the line portion LP of the magnetic track line MTL perpendicularly (e.g., in a second direction D2), and may not overlap the end portion EP of the magnetic track line MTL perpendicularly (e.g., in the second direction D2).

[0072] In one implementation, the magnetic track line MTL may be configured to have substantially the same characteristics as the magnetic track line MTL described with reference to Figure 6A and Figure 6B . In this case, the magnetic storage device according to this implementation may be used as a single-bit storage device.

[0073] In one implementation, the magnetic track line MTL may be configured to have substantially the same characteristics as the magnetic track line MTL described with reference to Figure 7A and Figure 7B . In this case, the magnetic storage device according to this implementation may be used as a multi-bit storage device.

[0074] Figure 9A is a plan view showing the magnetic storage device, Figure 9B is a cross-sectional view taken along line III-III' of Figure 9A . For simplicity, the following will mainly describe components different from those in the magnetic storage device described with reference to Figure 6A , Figure 6B , Figure 7A and Figure 7B .

[0075] With reference to Figure 9A and Figure 9B, a plurality of read devices 200 can be provided on the line portion LP of the magnetic track line MTL. Each read device 200 can overlap the line portion LP perpendicularly (e.g., in the second direction D2). In one implementation, the plurality of read devices 200 can be electrically separated from each other and can be configured to independently perform their own read operations. In one implementation, the plurality of read devices 200 can be connected in parallel with each other and can be configured to perform read operations in parallel.

[0076] In one implementation, the magnetic track line MTL can be configured to have substantially the same characteristics as the magnetic track line MTL described with reference to Figure 6A and Figure 6B . In this case, the magnetic storage device according to this implementation can be used as a single-bit storage device.

[0077] In one implementation, the magnetic track line MTL can be configured to have substantially the same characteristics as the magnetic track line MTL described with reference to Figure 7A and Figure 7B . In this case, the magnetic storage device according to this implementation can be used as a multi-bit storage device.

[0078] The magnetic track line can have a synthetic antiferromagnetic structure in which a lower magnetic layer and an upper magnetic layer are antiferromagnetically coupled to each other through an exchange coupling layer therebetween, and can include a spacer layer interposed between the exchange coupling layer and the upper magnetic layer. The lower magnetic layer can have an FCC (111) texture or an HCP (001) texture, and in this case, the strength of the antiferromagnetic coupling between the lower magnetic layer and the upper magnetic layer can be increased. This enables effective movement of magnetic domains in the magnetic track line (e.g., lower magnetic domains in the lower magnetic layer and upper magnetic domains in the upper magnetic layer). The spacer layer can block the FCC (111) texture or the HCP (001) texture of the lower magnetic layer and can accelerate the crystal growth of the upper magnetic layer. In this case, the upper magnetic layer can have a BCC (001) texture. Since the upper magnetic layer has a BCC (001) texture, a magnetic tunnel junction provided as a read device can have improved tunneling magnetoresistance characteristics.

[0079] In the magnetic storage device, high efficiency of magnetic domain movement in the magnetic track line can be achieved and improved tunneling magnetoresistance characteristics of the magnetic tunnel junction used as a read device can be achieved.

[0080] Although this disclosure contains many specific implementation details, these should not be construed as limitations on the scope of the claimed subject matter. Certain features described in the context of separate implementations in this disclosure can also be implemented in combination in a single implementation. Conversely, the various features described in the context of a single implementation can also be implemented separately in multiple implementations or in any suitable sub-combination. Additionally, although the features may be described above as acting in certain combinations, in some cases one or more features from a combination can be removed from the combination, and the combination can be directed to a sub-combination or a variation of the sub-combination. In this application, "plurality" means two or more than two.

[0081] Although example implementations have been specifically shown and described, those of ordinary skill in the art will understand that changes in form and detail can be made therein without departing from the spirit and scope of the appended claims.

[0082] This application claims the priority of Korean Patent Application No. 10-2023-0187944, filed with the Korean Intellectual Property Office on December 21, 2023, the entire content of which is incorporated herein by reference.

Claims

1. A magnetic storage device, comprising: A conductive line extending in a first direction; A magnetic track line provided on the conductive line and extending in the first direction; as well as A non-magnetic line is provided on the magnetic track line and extends in the first direction, The magnetic track lines include: A lower magnetic layer and an upper magnetic layer stacked on the conductive line; an exchange coupling layer between the lower magnetic layer and the upper magnetic layer; and a spacer layer between the exchange coupling layer and the upper magnetic layer, wherein the exchange coupling layer contacts the bottom surface of the spacer layer, and The lower magnetic layer and the upper magnetic layer are antiferromagnetically coupled to each other through the exchange coupling layer.

2. The magnetic memory device according to claim 1, wherein a face-centered cubic structure (111) crystal plane or a hexagonal closest-packed structure (001) crystal plane of the lower magnetic layer is parallel to an interface between the lower magnetic layer and the exchange coupling layer. 3 . The magnetic memory device according to claim 1 , wherein a body-centered cubic structure (001) crystal plane of the upper magnetic layer is parallel to an interface between the upper magnetic layer and the nonmagnetic wire.

4. The magnetic memory device according to claim 1, wherein the lower magnetic layer comprises: a plurality of lower magnetic domains arranged in the first direction, and a lower magnetic domain wall located between adjacent lower magnetic domains in the plurality of lower magnetic domains, The upper magnetic layer comprises: a plurality of upper magnetic domains arranged in the first direction, and an upper magnetic domain wall located between adjacent upper magnetic domains among the plurality of upper magnetic domains, and The plurality of upper magnetic domains are respectively overlapped vertically with the plurality of lower magnetic domains. 5 . The magnetic memory device according to claim 1 , wherein the spacer layer comprises a non-magnetic metal element. The magnetic memory device according to claim 1 , wherein the nonmagnetic wire comprises a metal oxide.

7. The magnetic memory device according to claim 1, further comprising a reference magnetic pattern on the nonmagnetic line, The reference magnetic pattern has a magnetization direction fixed to a specific direction.

8. The magnetic memory device according to claim 7, wherein the reference magnetic pattern comprises: The first is pinned pattern; a second pinned pattern between the first pinned pattern and the nonmagnetic wire; as well as a first non-magnetic pattern between the first pinned pattern and the second pinned pattern, The first pinned pattern and the second pinned pattern are antiferromagnetically coupled to each other through the first non-magnetic pattern.

9. The magnetic memory device according to claim 7, wherein the lower magnetic layer includes a plurality of lower magnetic domains arranged in the first direction, The upper magnetic layer includes a plurality of upper magnetic domains arranged in the first direction, and The reference magnetic pattern vertically overlaps a corresponding one of the plurality of lower magnetic domains and a corresponding one of the plurality of upper magnetic domains, thereby forming a magnetic tunnel junction. 10 . The magnetic memory device of claim 9 , wherein the lower magnetic layer, the upper magnetic layer, and the reference magnetic pattern have perpendicular magnetic anisotropy. 11 . The magnetic memory device according to claim 1 , wherein the conductive line is configured to generate a spin-orbit torque by a current flowing through the conductive line.

12. A magnetic storage device comprising: A conductive line extending in a first direction; a magnetic track line provided on a top surface of the conductive line and extending in the first direction; as well as With reference to the magnetic pattern, on the magnetic track line, The magnetic track lines include: A lower magnetic layer and an upper magnetic layer stacked on the conductive line; an exchange coupling layer between the lower magnetic layer and the upper magnetic layer; and a spacer layer between the exchange coupling layer and the upper magnetic layer, wherein the bottom surface of the spacer layer is in contact with the exchange coupling layer, A top surface of the spacer layer contacts the upper magnetic layer, and The lower magnetic layer and the upper magnetic layer are antiferromagnetically coupled to each other through the exchange coupling layer. 13 . The magnetic memory device according to claim 12 , wherein the spacer layer contains a nonmagnetic metal element.

14. The magnetic memory device according to claim 12, wherein a face-centered cubic structure (111) crystal plane or a hexagonal closest-packed structure (001) crystal plane of the lower magnetic layer is parallel to an interface between the lower magnetic layer and the exchange coupling layer.

15. The magnetic memory device according to claim 14, further comprising a non-magnetic line between the magnetic track line and the reference magnetic pattern, wherein the upper magnetic layer is interposed between the spacer layer and the nonmagnetic wire, and A (001) crystal plane of a body-centered cubic structure of the upper magnetic layer is parallel to an interface between the upper magnetic layer and the nonmagnetic wire. 16 . The magnetic memory device according to claim 15 , wherein a face-centered cubic structure (001) crystal plane of the nonmagnetic wire is parallel to the interface between the upper magnetic layer and the nonmagnetic wire. 17 . The magnetic memory device of claim 15 , wherein the non-magnetic line extends in the first direction to cover portions of the magnetic track line at both sides of the reference magnetic pattern.

18. The magnetic memory device according to claim 12, wherein the lower magnetic layer comprises: a plurality of lower magnetic domains arranged in the first direction, and a lower magnetic domain wall located between adjacent lower magnetic domains in the plurality of lower magnetic domains, The upper magnetic layer comprises: a plurality of upper magnetic domains arranged in the first direction, and an upper magnetic domain wall located between adjacent upper magnetic domains among the plurality of upper magnetic domains, and The plurality of upper magnetic domains are respectively overlapped vertically with the plurality of lower magnetic domains.

19. The magnetic memory device according to claim 18, wherein the reference magnetic pattern has a fixed magnetization direction, and The reference magnetic pattern vertically overlaps a corresponding one of the plurality of lower magnetic domains and a corresponding one of the plurality of upper magnetic domains, thereby forming a magnetic tunnel junction. 20 . The magnetic memory device of claim 12 , wherein the conductive line is configured to generate a spin-orbit torque by a current flowing through the conductive line.

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