MRAM-based chip identification with free random programming

Abstract

A magnetoresistive random access memory (MRAM) device is provided with chip identification at normal operating voltages. No dedicated programming is required. Instead, programming of the MRAM device is free and random, and is the result of providing a magnetic via structure close enough to a magnetic free layer of a magnetic tunnel junction (MTJ) structure so that the magnetic via structure projects a magnetic field that interacts with the magnetic free layer and aligns the magnetization of the magnetic free layer with that of the magnetic via structure. Thus, the magnetization orientations of both the magnetic via structure and the magnetic free layer are aligned in the same direction. In this way, the magnetization of the magnetic via structure can be used as a physical copy protection feature, and the MTJ structure can be used to read this information.

Description

[Technical Field]

[0001] This application relates to non-volatile memory, and more particularly to magnetoresistive random access memory (MRAM) devices having chip identification obtained without the need for dedicated programming.

[0002] Chip identification is essential to prevent counterfeiting and may also be used for device authentication. Traditional approaches to chip identification include the use of fuses, antifuses, or nonvolatile memory (NVM). After chip fabrication, a dedicated programming operation is required to embed unique identification information into each chip. Programming after chip fabrication has several drawbacks. First, such chip identification methods increase chip fabrication costs and may result in programming problems. Second, some chip identification approaches require high-voltage operation. For example, programming electrical fuses and antifuses requires high voltages. High-voltage supplies require complex circuitry (e.g., charge pumping), which increases chip size and manufacturing costs. Therefore, there is a need for improved chip identification. Summary of the Invention

[0003] A magnetoresistive random access memory (MRAM) device with chip identification is provided. Dedicated programming for chip identification is not required. Instead, programming of the MRAM device is free and random, relying on the magnetic properties of the magnetic tunnel junction (MTJ) structure. sex The magnetic free layer is adjacent to the sex This is the result of providing a via structure. sex The via structure is the magnetic sex located close enough to the free layer (i.e., sex The via structure is magnetic sexThis means that the distance separating the free layer from the magnetic sex The via structure is sex A magnetic field that interacts with the free layer, sex Free layer magnetization Vector direction The magnetic sex Magnetization of via structures Vector direction Therefore, the magnetic field in the disclosed MRAM device sex Via structure and magnetic sex The magnetization vectors of the free layers are aligned in the same direction. sex The magnetization of the via structure can be used as a physical unclonable function (PUF), and the MTJ structure can be used to read out this information.

[0004] In one aspect of the present application, there is provided an MRAM device. In one embodiment, the MRAM device comprises a magnetic memory device disposed above a substrate. sex In some embodiments, the magnetic layer includes a stack of a via structure and a first electrode. sex In another embodiment, a via structure is disposed under the first electrode. sex The via structure is disposed above the first electrode. sex The MTJ structure further includes a first interconnect dielectric material layer that embeds both the via structure and the first electrode, and the MTJ structure is disposed on the stack. sex The free layer is magnetic sex The MRAM device further includes a second electrode disposed on the MTJ structure. sex The via structure is sex a magnetic field that interacts with the free layer, sex Free layer magnetization Vector direction The magnetic sex Magnetization of via structures Vector directionThat is, the magnetic field aligns the sex Via structure and the magnetic sex The magnetization vectors of both free layers are oriented in the same direction.

[0005] In another aspect of the present application, a non-volatile memory (NVM) array is provided. In one embodiment, the NVM array includes a plurality of spaced apart MRAM devices disposed on a substrate, each MRAM device of the plurality of MRAM devices having a magnetic sex A stack of a via structure and a first electrode, and the magnetic sex a first interconnect dielectric material layer that embeds both the via structure and the first electrode; and an MTJ structure disposed on the stack, the MTJ structure having a magnetic sex The free layer is magnetic sex a MTJ structure including a tunnel barrier layer separating the reference layer from the reference layer, and a second electrode disposed on the MTJ structure; sex The via structure is sex a magnetic field that interacts with the free layer, sex Free layer magnetization Vector direction The magnetic sex Magnetization of via structures Vector direction It has a magnetic field that aligns with [Brief explanation of the drawings]

[0006] [Figure 1A] 1 is a cross-sectional view of an MRAM device including a magnetic via structure proximate to a magnetic free layer of an MTJ structure according to an embodiment of the present application, where the magnetic field generated by the magnetic via structure is not shown in this drawing. [Figure 1B] 1B is a cross-sectional view of the same MRAM device as FIG. 1A, illustrating the magnetic field generated by the magnetic via structure, according to an embodiment of the present application. [Figure 2] 1 is a cross-sectional view of an MRAM device including a magnetic via structure proximate to a magnetic free layer of an MTJ structure according to another embodiment of the present application, where the magnetic field generated by the magnetic via structure is shown. [Figure 3]10 is a cross-sectional view of an MRAM device including a magnetic via structure proximate to a magnetic free layer of an MTJ structure according to a further embodiment of the present application, where the magnetic field generated by the magnetic via structure is shown. [Figure 4A] 1C is a three-dimensional view of a portion of the MRAM device shown in FIGS. 1A and 1B, where the MRAM device has zero (0) as an output. [Figure 4B] FIG. 2 is a three-dimensional view of a portion of the MRAM device shown in FIGS. 1A and 1B, where the MRAM device has one (1) as an output. [Figure 5A] 3 is a three-dimensional view of a portion of the MRAM device shown in FIG. 2, where the MRAM device has zero (0) as an output. [Figure 5B] 3 is a three-dimensional view of a portion of the MRAM device shown in FIG. 2, where the MRAM device has one (1) as an output. [Figure 6A] 4 is a three-dimensional view of a portion of the MRAM device shown in FIG. 3, where the MRAM device has zero (0) as an output. [Figure 6B] FIG. 4 is a three-dimensional view of a portion of the MRAM device shown in FIG. 3, where the MRAM device has one (1) as an output. [Figure 7A] 1 shows an array of MTJ-containing MRAM devices magnetically coupled to magnetic via structures, where the direction of the magnetization vector of each magnetic free layer present in the MTJ structure follows the direction of the magnetization vector of the magnetic via structure. [Figure 7B] FIG. 7B is a circuit diagram of one of the MTJ-containing MRAM devices contained within the dotted circle shown in FIG. 7A. DETAILED DESCRIPTION OF THE INVENTION

[0007] The present application will now be described in more detail with reference to the following discussion and drawings attached hereto. It should be noted that the drawings herein are provided for illustrative purposes only, and as such, the drawings are not drawn to scale. It should also be noted that like and corresponding elements are referred to by like reference numerals.

[0008] In the following description, numerous specific details are set forth, such as particular structures, components, materials, dimensions, processing steps, and techniques, to provide an understanding of various embodiments of the present application. However, those skilled in the art will understand that various embodiments of the present application may be practiced without these specific details. In other instances, well-known structures or processing steps have not been described in detail to avoid obscuring an understanding of the present application.

[0009] When an element, such as a layer, region, or substrate, is referred to as being "on" or "over" another element, it is understood that it may be directly on the other element, or that intervening elements may be present. In contrast, when an element is referred to as being "directly on" or "directly over" another element, there are no intervening elements present. Also, when an element is referred to as being "beneath" or "under" another element, it is understood that it is directly under the other element, or that intervening elements may be present. In contrast, when an element is referred to as being "directly beneath" or "directly under" another element, there are no intervening elements present.

[0010] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that as used herein, the terms "comprises," "comprising," or combinations thereof specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, groups thereof, or combinations thereof.

[0011] As described above, an MRAM device with chip identification is provided. No dedicated programming for chip identification is required. Instead, programming of the MRAM device is free and random, and the magnetic fields of the MTJ structure are automatically programmed. sex Magnetic fields close enough (i.e., in close proximity) to the free layer sex As a result of providing a via structure, sex Interacts with the free layer and magnetic sex Free layer magnetization Vector direction The magnetic sex Magnetization of via structures Vector direction The magnetic field that aligns with sex The via structure is projected. sex From the top of the via structure to the magnetic sex the distance (measured from the free layer to the bottom surface) is 30 nm or less, and the distance of 30 nm or less is the magnetic sex The via structure is magnetic sex Separation from the free layer. sex The presence of the magnetic via structure close to the free layer allows the magnetic via structure and the magnetic sex Both magnetizations of the free layer Vector The directions of the magnets are aligned in the same direction. sex The magnetization of the via structure can be used as a physical anti-copy feature, and the MTJ structure can be used to read this information. These and other aspects of the present application are now described in more detail.

[0012] Referring first to FIG. 1A, in accordance with an embodiment of the present application, the magnetic field of the MTJ structure (18 / 20 / 22) is sex The magnetic sex An MRAM device is shown including a via structure 12. As previously defined, the term "proximate to" refers to a magnetic sex Via structure 12 is the magnetic sex To demonstrate that the magnetic via structure 12 is placed close enough to the free layer 22 (i.e., the magnetic via structure 12 is separated from the magnetic free layer 22 by a distance of 30 nm or less), it is necessary to interact with the magnetic free layer 22 and change the magnetization of the magnetic free layer 22. Vector direction The magnetization of the magnetic via structure 12 Vector directionThe magnetic via structure 12 projects a magnetic field (see not only FIG. 1B but also FIGS. 2 and 3) that aligns the magnetic field. sex Via structure 12 and magnetic sex The magnetization vectors of the free layer 22 are oriented in the same direction.

[0013] In Figure 1A, the magnetic sex Although the magnetic field generated by the via structure 12 is not shown, FIG. 1B illustrates the magnetic field generated by the MRAM device of FIG. 1A. sex 1A-1B (and FIGS. 2-3) illustrate the magnetic field M generated by via structure 12, and also illustrate the magnetic field M for alternative MRAM devices of the present application. Note that FIGS. 1A-1B (and FIGS. 2-3) illustrate memory device areas of a back-end-of-the-line (BEOL) structure in which the present MRAM devices reside. Non-memory device areas of the BEOL structure may be located adjacent to and at the periphery of the memory device areas shown in FIGS. 1A, 1B, 2, and 3. The non-memory device areas may include other BEOL devices / structures, including, for example, BEOL resistors and / or BEOL interconnect structures.

[0014] In particular, the MRAM device of FIGS. 1A-1B includes a magnetic sex The via structure 12 is provided with a first electrode 14. sex A first interconnect dielectric material layer 16 is disposed over the via structure 12 and includes a magnetic sex Both the via structure 12 and the first electrode 14 are embedded, and the MTJ structure (18 / 20 / 22) is disposed on the first electrode 14. The MTJ structure (18 / 20 / 22) is a magnetic sex The free layer 22 is sex 1A-1B includes a tunnel barrier layer 20 separating it from the reference layer 18. The MRAM device of Figures 1A-1B further includes a second electrode 24 disposed on the MTJ structure (18 / 20 / 22). In this application, the first electrode 12 may be referred to as a bottom electrode, and the second electrode 24 may be referred to as a top electrode 24.

[0015] The MRAM device of FIGS. 1A-1B may further include a contact structure 30 disposed on the second electrode 24 and contacting a surface of the second electrode 24. As shown in FIGS. 1A-1B, the contact structure 30 and the MTJ structures (18 / 20 / 22) are both embedded in a second interconnect dielectric material layer 28. In some embodiments, as shown in FIGS. 1A-1B, a dielectric material liner 26 may be present entirely along the sidewalls of both the second electrode 24 and the MTJ structures (18 / 20 / 22) and on the surface of the first interconnect dielectric material layer 16. In some embodiments, the dielectric material liner 26 may be present entirely along the sidewalls of the MTJ structures (18 / 20 / 22) and partially along the bottom of the sidewalls of the second electrode 24. In such embodiments, a portion of the contact structure 30 may contact the top of the sidewalls of the second electrode 24. In some embodiments, the dielectric material liner 26 may be omitted.

[0016] The MRAM device shown in Figures 1A and 1B (and Figures 2-3) can be fabricated using techniques well known in the art, including various deposition processes, lithographic patterning, etching, and planarization. Details regarding the processing techniques used to fabricate the MRAM device will not be provided herein to avoid obscuring the scope of the present application. Each component of the MRAM device shown in Figures 1A and 1B will now be described in more detail.

[0017] A first interconnect dielectric material layer 16 and a magnetic sexThe substrate 10 disposed below the via structure 12 and the stack of first electrodes 14 may be a front-end-of-the-line (FEOL) level, a metal level, or any combination thereof, with FEOL representing the lowest level of the substrate 10. The FEOL level may include one or more complementary metal-oxide-semiconductor (CMOS) devices disposed on or within a semiconductor substrate. For example, a field-effect transistor (FET) may be disposed on the semiconductor substrate. The metal level may be a middle-of-the-line (MOL) level and / or one or more lower interconnect levels. The metal level may include one or more conductive structures (e.g., copper (Cu) structures, aluminum (Al) structures, tungsten (W) structures, or combinations thereof) embedded within one or more layers of dielectric material. The one or more dielectric material layers of the metal level can be composed of any suitable dielectric material, such as, for example, a low-k dielectric (i.e., a dielectric material having a dielectric constant less than that of silicon dioxide, i.e., less than about 3.9), an ultra low-k dielectric material (i.e., a dielectric material having a dielectric constant less than 3.0), or a combination thereof. Dielectric constants referred to herein are measured in a vacuum unless otherwise specified. In some embodiments, the one or more dielectric material layers of the metal level can include silicon dioxide. In one embodiment of the present invention, the substrate 10 includes, from bottom to top, a FEOL level, a MOL level, and one or more interconnect levels.

[0018] A magnetic layer disposed above the substrate 10 and embedded in a first layer of interconnect dielectric material 16. sex The via structure 12 is made of a magnetic material. sex Examples of magnetic materials that can provide the via structure 12 include, but are not limited to, cobalt (Co), tungsten (W), nickel (Ni), or alloys thereof. sex One example of a magnetic alloy that can be used as the magnetic material of the via structure 12 is a Co-Ni alloy.

[0019] The Magnet of the Original Desire sexThe via structure 12 has a high aspect ratio (i.e., ratio of height to diameter) of greater than 2:1. sex The via structure 12 has an aspect ratio of 5:1 to 100:1. sex The via structure 12 is typically cylindrical, although other asymmetric shapes are possible, and may be magnetic. sex Any shape of via structure 12 can be used in the present application.

[0020] In accordance with this application, sex The via structure 12 generates a magnetic field MF, as shown in FIG. 1B, which interacts with the magnetic free layer 22 and increases the magnetization of the magnetic free layer 22. Vector direction The magnetic sex Magnetization of via structure 12 Vector direction Therefore, the magnetic field in the MRAM device of this application is sex Via structure 12 and magnetic sex The magnetization vectors of the free layer 22 are oriented in the same direction.

[0021] Applicant believes that after processing the MRAM device of the present application, the magnetic sex It is observed that the via structure 12 has magnetization (i.e., magnetic vector) pointing in a single direction. sex Magnetization of via structure 12 Vector In another embodiment of the present invention, the magnetic sex Magnetization of via structure 12 Vector The applicant has sex Immediately after the formation of the via structure 12, sex Magnetization of via structure 12 Vector Note that the magnetic field may not be pointing up or down. However, during processing of the MRAM device of the present application, sex The magnetization of the via structure 12 typically relaxes either up or down toward its minimum energy state, and the magnetization of the magnetic free layer 22 Vector follows and becomes magnetic sex The magnetization of the via structure 12 is oriented in the same direction as the magnetization of the via structure 12. sex Magnetization of via structure 12 Vector direction is random and magnetic sex It should be noted that this depends on the aspect ratio of the via structure 12. sex The via structure 12 can be used as a PUF and the MTJ structures (18 / 20 / 22) can read this information.

[0022] In the embodiment shown in FIGS. sex The via structure 12 has a first surface that forms a first interface with the surface of the substrate 10 and a second surface opposite the first surface that forms a second interface with the surface of the first electrode 14. In the embodiment shown in FIGS. sex The via structure 12 is disposed below the first electrode 14 .

[0023] In the embodiment shown in FIGS. 1A-1B, the first electrode 14 is a magnetic sex The first electrode 14 may be made of a magnetic material that can further add to the magnetic field strength of the via structure 12. Examples of magnetic materials that can provide the first electrode 14 include cobalt (Co), nickel (Ni), tungsten (W), iron (Fe), and magnetic rare earth metals, including, but not limited to, gadolinium (Gd), neodymium (Nd), or alloys thereof. The magnetic material that provides the first electrode 14 can be compositionally the same as or compositionally different from the magnetic material that provides the magnetic via structure 12. In one embodiment, the first electrode 14 and the magnetic sex Both via structures 12 are comprised of Co. In another embodiment, first electrode 14 is comprised of W and magnetic sex The via structure 12 is made of Co. In FIGS. 1A and 1B, the first electrode 14 and the magnetic sex Dotted lines are shown as possible locations of material interfaces that may exist between via structures 12 .

[0024] The first electrode 14 is typically cylindrical, although other asymmetric shapes are possible and may be used herein as the shape of the first electrode 14. Typically, but not always, the shape of the first electrode 14 is determined by the magnetic field. sex The first electrode 14 may have a critical dimension (CD) (i.e., diameter) that matches the shape of the via structure 12. The critical dimension (CD) may be a magnetic sex 1A-1B show that the CD of the first electrode 14 is smaller than or equal to the CD, i.e., diameter, of the via structure 12. sex An embodiment is shown that is smaller than the CD of the via structure 12. The first electrode 14 can have an aspect ratio that is between 1:1 and 1:5.

[0025] In the embodiment of FIGS. 1A-1B, the first electrode 14 is a magnetic sex 1A-1B, the second surface of first electrode 14 that forms the second interface with the surface of MTJ structure (18 / 20 / 22) is coplanar with a non-recessed surface NS of first interconnect dielectric material layer 16.

[0026] magnetic sex The first interconnect dielectric material layer 16, which laterally surrounds the stack including the via structure 12 and the first electrode 14, can comprise one or more interconnect dielectric materials. When more than one interconnect dielectric material is used to provide the first interconnect dielectric material layer 16, each dielectric material providing the first interconnect dielectric material layer 16 is stacked on top of each other. In some embodiments where more than one interconnect dielectric material is used to provide the first interconnect dielectric material layer 16, each dielectric material providing the first interconnect dielectric material layer 16 can be composed of a compositionally identical interconnect dielectric material. In other embodiments where more than one interconnect dielectric material is used to provide the first interconnect dielectric material layer 16, compositionally different interconnect dielectric materials can be used to provide the first interconnect dielectric material. In such embodiments, magnetic sexThe via structure 12 may be embedded in a lower portion of a first interconnect dielectric material layer 16 comprised of a first interconnect dielectric material, while the first electrode 14 may be embedded in an upper portion of the first interconnect dielectric material layer 16 comprised of a second interconnect dielectric material that is compositionally different from the first interconnect dielectric material. In such an embodiment, a material interface (not shown) exists between the first and second dielectric materials used to provide the first interconnect dielectric material layer 16.

[0027] Examples of interconnect dielectric materials that can be used as first interconnect dielectric material layer 16 include, but are not limited to, silicon dioxide, a low-k dielectric material as defined above, an ultra low-k dielectric material as defined above, or combinations thereof. First interconnect dielectric material layer 16 can be porous or non-porous, or can include at least one porous region and at least one non-porous region.

[0028] 1A and 1B, the first interconnect dielectric material layer 16 has a recessed surface RS disposed adjacent to a non-recessed surface NS. In such embodiments, the non-recessed surface NS (i.e., the top surface) of the first interconnect dielectric material layer 16 can be coplanar with the top surface of the first electrode 14. The recessed surface RS can be formed during the patterning process used to form the MTJ structure (18 / 20 / 22) and the second electrode 24. In some embodiments, the recessed surface RS is not present in the first interconnect dielectric material layer 16. In such embodiments, the first interconnect dielectric material layer 16 has a top surface that is entirely non-recessed.

[0029] The MTJ structure (18 / 20 / 22) that can be used in this application is sex The reference layer 18 is sex It includes at least a tunnel barrier layer 20 separating it from a free layer 22. The present MTJ structure (18 / 20 / 22) is designed to have a low coercive field, so that the magnetic sexThe magnetization of the free layer 22 is sex It naturally aligns with the magnetization of the via structure 12. In one example, the "low coercive field" is 500 Oe or less.

[0030] In this application, the magnetic sex The arrangement of the free layer 22 is the same as that of the magnetic sex The reference layer 18 may vary relative to the reference layer 18. For example, in some embodiments illustrated in various figures herein, the MTJ structure (18 / 20 / 22) is configured from bottom to top with a magnetic sex The reference layer 18, the tunnel barrier layer 20, and the magnetic sex 1A-1B, the free layer 22 is a bottom-pinned MTJ structure. sex The reference layer 18 can form an interface with the underlying first electrode 14 .

[0031] In another embodiment of the present application (which can be easily seen from the various figures of the present application by flipping the MTJ structure (18 / 20 / 22) by 180 degrees), the MTJ structure (18 / 20 / 22) is magnetically sex The free layer 22, the tunnel barrier layer 20, and the magnetic sex The reference layer 18 is a top-pinned MTJ structure. sex In the case where the via structure 12 is disposed above the sex The free layer 22 can form an interface with the underlying first electrode 14 .

[0032] Magnetic materials that can be used in this application as elements of MTJ structures (18 / 20 / 22) sex The reference layer 18 has a fixed magnetization. sex The magnetization of the reference layer 18 points in one direction, e.g., up or down, regardless of the magnetization of other neighboring magnetic layers. sex The reference layer 18 can be called a magnetic pinned layer. sexThe reference layer 18 can be composed of a metal or metal alloy that includes one or more metals that exhibit high spin polarization. sex Examples of metals for the reference layer 18 include iron (Fe), nickel (Ni), cobalt (Co), chromium (Cr), boron (B), and manganese (Mn). sex An example metal alloy for reference layer 18 can include two or more of the above-listed metals. sex The reference layer 18 may be a multilayer arrangement having (1) high spin polarization regions formed from metals and / or metal alloys using the metals listed above, and (2) regions composed of one or more materials exhibiting strong perpendicular magnetic anisotropy (strong PMA). Examples of materials exhibiting strong PMA that can be used include metals such as cobalt (Co), nickel (Ni), platinum (Pt), palladium (Pd), iridium (Ir), or ruthenium (Ru), which may be arranged as alternating layers. The strong PMA regions may also include alloys exhibiting strong PMA, such as cobalt-iron-terbium, cobalt-iron-gadolinium, cobalt-chromium-platinum, cobalt-platinum, cobalt-palladium, iron-platinum, iron-palladium, or combinations thereof. The alloys may be arranged as alternating layers. In one embodiment, combinations of these materials and regions may also be employed.

[0033] The tunnel barrier layer 20 that can be used herein as a component of the MTJ structure (18 / 20 / 22) is made of an insulating material and formed to a thickness that provides an appropriate tunneling resistance. Examples of materials for the tunnel barrier layer 20 include magnesium oxide, aluminum oxide, and titanium oxide, or materials with higher electrical tunneling conductance, such as semiconductors or low bandgap insulators.

[0034] Magnetic materials that can be used in this application as elements of MTJ structures (18 / 20 / 22) sex The free layer 22 is composed of at least one magnetic material whose magnetization can be changed. sexExamples of materials for the free layer 22 include alloys and / or multilayers of cobalt, iron, cobalt-iron alloys, nickel, nickel-iron alloys, and cobalt-iron-boron alloys. sex The orientation of the magnetization of the free layer 22 is affected by the magnetic field generated by the magnetic via structure 12. sex Magnetization of the free layer 22 Vector direction The magnetization of the magnetic via structure 12 Vector direction Align it with:

[0035] In some embodiments, the non-magnetic metal spacer layer is sex In such an embodiment, a non-magnetic metal spacer layer may be present in the free layer 22. sex The free layer 22 is a first magnetic sex Free layer and second magnetic sex The non-magnetic metal spacer layer, when present, is composed of a non-magnetic metal or non-magnetic metal alloy that allows magnetic information to be transmitted therethrough and separates the two magnetic sex To allow the free layer portions to be magnetically coupled, the first and second magnetic sex The free layer portion is always parallel. The non-magnetic metal spacer layer sex The first and second magnetic layers of the free layer 22 sex It allows spin torque switching between the free layer portions.

[0036] In some embodiments (not shown) where the magnetic free layer 22 is located at the bottom of the MTJ structure, a metallic seed layer can be located between the first electrode 14 and the magnetic free layer 22. This optional metallic seed layer can be composed of platinum (Pt), palladium (Pd), nickel (Ni), iridium (Ir), rhenium (Re), or alloys and multilayers thereof.

[0037] In some embodiments (not shown), an MTJ cap layer is present as the top layer of the MTJ structure (18 / 20 / 22), and the MTJ cap layer forms an interface with the second electrode 24. The MTJ cap layer, if present, can be composed of niobium (Nb), niobium nitride (NbN), tungsten (W), tungsten nitride (WN), tantalum (Ta), tantalum nitride (TaN), titanium (Ti), titanium nitride (TiW), ruthenium (Ru), molybdenum (Mo), chromium (Cr), vanadium (V), palladium (Pd), rhodium (Ru), scandium (Sc), aluminum (Al), or other refractory conductive metals or conductive metal nitrides.

[0038] Although the MTJ structures (18 / 20 / 22) are typically cylindrical, other asymmetric shapes are also possible and can be used herein as the shape of the MTJ structures (18 / 20 / 22). The CD of the MTJ structures (18 / 20 / 22) can be equal to, smaller than, or larger than the CD of the underlying first electrode 14. A critical dimension of the MTJ structures (18 / 20 / 22) that is larger than the CD of the underlying first electrode 14 is preferred because this prevents metal residue from the underlying first electrode 14 from depositing on the sidewalls of the MTJ structures (18 / 20 / 22) during the formation of the MTJ structures (18 / 20 / 22), which typically involves depositing the various layers of the MTJ structures (18 / 20 / 22) and patterning the deposited layers using an ion beam etching process. The presence of metal residue on the sidewalls of the MTJ structures (18 / 20 / 22) could cause a short circuit in the MRAM device.

[0039] The second electrode 24 disposed on top of the MTJ structure (18 / 20 / 22) can be composed of a conductive material such as tantalum (Ta), tantalum nitride (TaN), titanium (Ti), titanium nitride (TiN), ruthenium (Ru), ruthenium nitride (RuN), ruthenium-tantalum (RuTa), ruthenium-tantalum nitride (RuTaN), cobalt (Co), cobalt-tungsten-phosphorus (CoWP) alloy, cobalt nitride (CoN), tungsten (W), tungsten nitride (WN), or any multilayer combination thereof. In one example of a multilayer combination, the second electrode 24 is composed of Ti / TiN.

[0040] The second electrode 24 is typically cylindrical, although other asymmetric shapes are possible and may be used herein as the shape of the second electrode 24. The shape of the second electrode 24 is typically the same as the shape of the MTJ structure (18 / 20 / 22). In one example, both the MTJ structure (18 / 20 / 22) and the second electrode 24 are cylindrical. The CD of the second electrode 24 is typically the same as the CD of the underlying MTJ structure (18 / 20 / 22).

[0041] The dielectric material liner 26, which may also be referred to as an encapsulation liner, is comprised of a dielectric material capable of providing passivation to the MTJ structure (18 / 20 / 22) and the second electrode 24. In one embodiment, the dielectric material liner 26 is comprised of silicon nitride. In another embodiment, the dielectric material liner 26 can be comprised of a dielectric material including atoms of silicon, carbon, and hydrogen. In some embodiments, in addition to atoms of carbon and hydrogen, the dielectric material providing the dielectric material liner 26 can include atoms of at least one of nitrogen and oxygen. In other embodiments, in addition to atoms of silicon, nitrogen, carbon, and hydrogen, the dielectric material providing the dielectric material liner 26 can include atoms of boron. In one example, the dielectric material liner 26 can be comprised of an nBLOK dielectric material including atoms of silicon, carbon, hydrogen, nitrogen, and oxygen. In an alternative example, the dielectric material liner 26 can be comprised of a SiBCN dielectric material including atoms of silicon, boron, carbon, hydrogen, and nitrogen. The dielectric material liner 26 typically has a top surface that is coplanar with the top surface of the top electrode 24 .

[0042] The second interconnect dielectric material layer 28 can include one of the interconnect dielectric materials described above for the first interconnect dielectric material layer 16. The interconnect dielectric material providing the second interconnect dielectric material layer 28 can be compositionally the same as or compositionally different from the interconnect dielectric material providing the first interconnect dielectric material layer 16.

[0043] The contact structure 30 embedded in the second interconnect dielectric material layer 28 comprises a conductive metal or conductive metal alloy. Examples of conductive materials that can be used to provide the contact structure 30 include, but are not limited to, copper (Cu), aluminum (Al), tungsten (W), or a Cu-Al alloy. The contact structure 30 may also include a diffusion barrier liner disposed along the sidewalls and bottom wall of the conductive material. If present, the diffusion barrier is comprised of a diffusion barrier material such as tantalum (Ta), tantalum nitride (TaN), titanium (Ti), titanium nitride (TiN), ruthenium (Ru), ruthenium nitride (RuN), a RuTa alloy, a RuTaN alloy, tungsten (W), tungsten nitride (WN), or a multilayer combination thereof. As shown, the contact structure 30 has a top surface that is coplanar with the top surface of the second interconnect dielectric material layer 28.

[0044] Referring now to FIG. 2, in accordance with another embodiment of the present application, the magnetic field of the MTJ structure (18 / 20 / 22) is sex The magnetic sex An MRAM device is shown including a via structure 12, which is shown in the drawing as a magnetic sex The magnetic field MF generated by the via structure 12 is shown. The MRAM device shown in Figure 2 is similar to the MRAM device shown in Figures 1A-1B, except that the first electrode 14 in this embodiment of the present application is composed of a non-magnetic conductive material rather than a magnetic material as in Figures 1A-1B. All other components / elements of the MRAM device in Figure 2 are the same as those described above for the MRAM device shown in Figures 1A-1B. Although Figures 2 and 3 show a bottom-pinned MTJ structure, the embodiment shown in Figures 2 and 3 will function equally well with a top-pinned MTJ structure.

[0045] In this embodiment, the non-magnetic conductive material providing the first electrode 14 may include, but is not limited to, tantalum (Ta), tantalum nitride (TaN), titanium (Ti), titanium nitride (TiN), ruthenium (Ru), ruthenium nitride (RuN), ruthenium-tantalum (RuTa), ruthenium-tantalum nitride (RuTaN), or any multilayer combination thereof. In one example of a multilayer combination, the first electrode 14 may be composed of Ti / TiN.

[0046] Referring to FIG. 3, according to a further embodiment of the present application, the magnetic sex The magnetic sex An MRAM device is shown including a via structure 12, which in this drawing is sex The magnetic field MF generated by the via structure is shown. The MRAM device shown in FIG. 3 is a device in which the first electrode 14 of this embodiment of the present application sex 1A-1B, except that it is located under via structure 12. All other components / elements of the MRAM device of FIG. 3 are the same as those described above for the MRAM device shown in FIGS. 1A-1B.

[0047] In the embodiment shown in FIG. 3, the first electrode 14 has a first surface that forms an interface with the surface of the substrate 10 and a magnetic sex and a second surface opposite the first surface that forms an interface with the first surface of the via structure 12. sex A magnetic sex The second surface of the via structure 12 forms an interface with the MTJ structure (18 / 20 / 22). In this embodiment, the magnetic sex The second surface of the via structure 12 is coplanar with the non-recessed surface NS of the first layer of interconnect dielectric material 26 .

[0048] In this embodiment of the present application, sex The via structure 12 can have a CD that is the same as or smaller than the CD of the underlying first electrode 14. In this embodiment, the magnetic sexThe via structure 12 still has a high aspect ratio.

[0049] In this embodiment, first electrode 14 is typically constructed of a non-magnetic, electrically conductive material, such as described above for first electrode 14 in the embodiment shown in Figure 2. In some examples, first electrode 14 can be constructed of a magnetic material, such as described above for first electrode 14 shown in Figures 1A-1B.

[0050] The present MRAM devices (as shown in Figures 1A, 1B, 2 and 3) have chip identification using normal operating voltages and without the need for dedicated programming. sex The spatial distribution of the fringing magnetic field MF generated by the via structure 12 is similar to that of the magnetic field of the MTJ structure (18 / 20 / 22). sex It extends to the free layer 22. sex The fringing magnetic field generated by the via structure 12 is sex It interacts with the magnetization of the free layer 22 and affects its orientation. sex Via structure 12 and magnetic sex Both magnetization vectors of the free layer 22 are randomly aligned in the same direction, either up or down. sex The magnetization of the reference layer 18 is fixed and always points in the same direction. In Figures 1B, 2, 3, 4A, 4B, 5A, 5B, 6A and 6B, single-headed arrows indicate the direction of magnetization of the various layers / components of the MRAM device. Programming of the MRAM devices herein is random, with the magnetization sex It is free because it is generated as a by-product of the via structure 12. sex The magnetization of the via structure 12 can be used as a physical anti-copy feature and the MTJ structure (18 / 20 / 22) can be used to read this information.

[0051] In this application, magnetic sex Via structure 12, magnetic sex The reference layer 18 and the magnetic sex Each of the free layers 22 has magnetization oriented in the same direction. Vector When the MTJ structure (18 / 20 / 22) has the magnetic sexVia structure 12 and magnetic sex The free layer 22 has magnetizations oriented in the same first direction. Vector It has a magnetic sex The reference layer 18 has a magnetization oriented in a second direction opposite to the first direction. Vector , the MTJ structure (18 / 20 / 22) can read one (1). This aspect of the present application is illustrated in Figures 4A, 4B, 5A, 5B, 6A, and 6C. The "0" and "1" are logical readouts that can be used as a means of chip identification.

[0052] Notably, in FIG. 4A, the magnetic sex Via structure 12, magnetic sex The reference layer 18 and the magnetic sex The free layer 22 has an all-up magnetization Vector Such an MRAM device has a zero (0) as an output. sex Via structure 12 and magnetic sex Both of the free layers 22 have downward magnetization Vector It has a magnetic sex Magnetization of the reference layer 18 Vector is pointing up. Such an MRAM device has zero (0) as its output.

[0053] In FIG. 5A, sex Via structure 12, magnetic sex The reference layer 18 and the magnetic sex The free layer 22 has an all-up magnetization Vector Such an MRAM device has a zero (0) as an output. sex Via structure 12 and magnetic sex Both of the free layers 22 have downward magnetization Vector It has a magnetic sex Magnetization of the reference layer 18 Vector is pointing up. Such an MRAM device has zero (0) as its output.

[0054] In Figure 6A, the magnetic sex Via structure 12, magnetic sex The reference layer 18 and the magnetic sex The free layer 22 has an all-up magnetization Vector Such an MRAM device has a zero (0) as an output. sex Via structure 12 and magnetic sex Both of the free layers 22 have downward magnetization Vector It has a magnetic sex Magnetization of the reference layer 18 Vector is pointing up. Such an MRAM device has zero (0) as its output.

[0055] Reference is now made to FIG. 7A, which illustrates an array of MTJ-containing MRAM devices 56, according to an embodiment of the present application. FIG. 7B illustrates a circuit diagram of one of the MTJ-containing MRAM devices 56 included within the dotted circle shown in FIG. 7A. The array shown in FIG. 7A includes a plurality of source lines SL1, SL2...SLm and a plurality of bit lines BL1, BL2...BLm, which are spaced apart from one another and arranged in columns. "m" is an integer greater than 2 in the example shown in FIG. 7A.

[0056] A first end of each of the source lines SL1, SL2...SLm and each of the bit lines BL1, BL2...BLm is electrically connected to a column decoder 52, and a second end of each of the source lines SL1, SL2...SLm and each of the bit lines BL1, BL2...BLm is electrically connected to a sense amplifier / analog-to-digital converter 50. An output "0" or "1" can be read from the array. The array further includes a plurality of word lines WL1, WL2...WLm arranged in rows. One end of each word line WL1, WL2...WLm is electrically connected to a row decoder 50. The word lines, bit lines, and source lines are conductive structures used in combination with the MRAM device of the present application to provide an integrated circuit. The array further includes a plurality of MTJ-containing MRAM devices 56. Each MTJ-containing MRAM device 56 includes a switching controller, such as a FET, and a magnetic field generating circuit, such as a FET, for generating an MRAM device according to the present application, i.e., a magnetic field generating circuit ... sexAdjacent to the free layer is a magnetic sex and MRAM devices including via structures. In the exemplary embodiment shown in Figure 7A, the gates of the FETs are connected to a word line WL, one of the source / drain regions of the FETs is connected to a source line SL, and the other of the source / drain regions of the FETs is connected to an MTJ structure, which is connected to a bit line BL. In the exemplary embodiment of Figure 7A, (reading from left to right) each MTJ-containing MRAM device 56 in a first column has a "1" as an output, each MTJ-containing MRAM device 56 in a second column has a "0" as an output, and each MTJ-containing MRAM device 56 in a third column has a "1".

[0057] While the present application has been particularly shown and described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and detail may be made therein without departing from the scope of the present application. It is therefore intended that the present application not be limited to the exact forms and details described and illustrated, but fall within the scope of the appended claims. One embodiment of the present invention is as follows. [Section 1] a stack of a magnetic via structure and a first electrode disposed above a substrate; a first interconnect dielectric material layer embedding both the magnetic via structure and the first electrode; a magnetic tunnel junction (MTJ) structure disposed on the stack, the MTJ structure including a tunnel barrier layer separating a magnetic free layer from a magnetic reference layer; a second electrode disposed on the MTJ structure; A magnetoresistive random access memory (MRAM) device, wherein the magnetic via structure has a magnetic field that interacts with the magnetic free layer of the MTJ structure, aligning the direction of the magnetization vector of the magnetic free layer with the direction of the magnetization vector of the magnetic via structure. [Section 2] Item 1. The MRAM device of item 1, further comprising a contact structure disposed on the second electrode and contacting a surface of the second electrode. [Section 3] Item 3. The MRAM device of item 2, wherein the contact structure and the MTJ structure are both embedded in a second interconnect dielectric material layer. [Section 4] Item 1. The MRAM device according to item 1, wherein the MTJ structure is a bottom-pinned MTJ structure. [Section 5] Item 1. The MRAM device according to item 1, wherein the MTJ structure is a top-pin MTJ structure. [Section 6] Item 1. The MRAM device according to item 1, wherein the magnetic via structure is disposed directly below the first electrode. [Section 7] Item 7. The MRAM device of item 6, wherein the magnetic via structure and the first electrode are both made of magnetic material. [Section 8] Item 8. The MRAM device of item 7, wherein the magnetic material of the magnetic via structure is compositionally the same as the magnetic material of the first electrode. [Section 9] Item 8. The MRAM device of item 7, wherein the magnetic material of the magnetic via structure is compositionally different from the magnetic material of the first electrode. [Section 10] Item 1. The MRAM device of item 1, wherein the magnetic via structure is made of a magnetic material and the first electrode is made of a non-magnetic but conductive material. [Section 11] Item 1. The MRAM device of item 1, wherein the magnetic via structure is disposed above the first electrode. [Section 12] Item 12. The MRAM device of item 11, wherein the magnetic via structure is made of a magnetic material and the first electrode is made of a non-magnetic but conductive material. [Section 13] Item 12. The MRAM device of item 11, wherein the magnetic via structure and the first electrode are both made of magnetic material. [Section 14] Item 1. The MRAM device of item 1, wherein the magnetic via structure has an aspect ratio greater than 2:1. [Section 15] Item 10. The MRAM device of item 1, wherein the magnetic reference layer has a magnetization vector direction that is the same as the magnetization vector direction of both the magnetic via structure and the magnetic free layer. [Section 16] Item 10. The MRAM device of item 1, wherein the magnetic reference layer has a magnetization vector direction that is different from the magnetization vector directions of both the magnetic via structure and the magnetic free layer. [Section 17] A non-volatile memory (NVM) array including a plurality of spaced apart magnetoresistive random access memory (MRAM) devices disposed on a substrate, each MRAM device of the plurality of MRAM devices includes a stack of a magnetic via structure and a first electrode, a first interconnect dielectric material layer embedding both the magnetic via structure and the first electrode, a magnetic tunnel junction (MTJ) structure disposed on the stack, the MTJ structure including a tunnel barrier layer separating a magnetic free layer from a magnetic reference layer, and a second electrode disposed on the MTJ structure; A non-volatile memory (NVM) array, wherein the magnetic via structure has a magnetic field that interacts with the magnetic free layer of the MTJ structure, aligning the direction of the magnetization vector of the magnetic free layer with the direction of the magnetization vector of the magnetic via structure. [Section 18] Item 18. The NVM array of item 17, wherein the magnetic reference layer of a first set of MRAM devices has a magnetization that is the same as the magnetization of both the magnetic via structure and the magnetic free layer in the first set of MRAM devices, and the magnetic reference layer of a second set of MRAM devices has a magnetization that is different from the magnetization of both the magnetic via structure and the magnetic free layer in the second set of MRAM devices. [Section 19] Item 18. The NVM array of item 17, wherein the magnetic via structure is disposed directly below the first electrode. [Section 20] Item 18. The NVM array of item 17, wherein the magnetic via structure is disposed directly above the first electrode.

Claims

1. 1. A magnetoresistive random access memory (MRAM) device, comprising: a stack of a magnetic via structure disposed above a substrate and a first electrode on the magnetic via structure; a first interconnect dielectric material layer embedding both the magnetic via structure and the first electrode; a magnetic tunnel junction (MTJ) structure disposed on the first electrode of the stack, the MTJ structure comprising a magnetic reference layer, a magnetic free layer, and a tunnel barrier layer separating the magnetic reference layer from the magnetic free layer; a second electrode disposed on the MTJ structure; It is equipped with the magnetic via structure has a magnetic field that interacts with the magnetic free layer of the MTJ structure, aligning a direction of a magnetization vector of the magnetic free layer with a direction of a magnetization vector of the magnetic via structure, the direction of the magnetization vector of the magnetic via structure is random and dependent on an aspect ratio of the magnetic via structure, and reading the magnetization vector provides chip identification for a chip including the MRAM device. The MRAM device.

2. 1. A magnetoresistive random access memory (MRAM) device, comprising: a stack of a first electrode disposed above a substrate and a magnetic via structure on the first electrode; a first interconnect dielectric material layer embedding both the first electrode and the magnetic via structure; a magnetic tunnel junction (MTJ) structure disposed on the magnetic via structure of the stack, the MTJ structure comprising a magnetic reference layer, a magnetic free layer, and a tunnel barrier layer separating the magnetic reference layer from the magnetic free layer; a second electrode disposed on the MTJ structure; It is equipped with the magnetic via structure has a magnetic field that interacts with the magnetic free layer of the MTJ structure, aligning a direction of a magnetization vector of the magnetic free layer with a direction of a magnetization vector of the magnetic via structure, the direction of the magnetization vector of the magnetic via structure is random and dependent on an aspect ratio of the magnetic via structure, and reading the magnetization vector provides chip identification for a chip including the MRAM device. The MRAM device.

3. 10. The MRAM device of claim 1, further comprising a contact structure disposed on the second electrode and contacting a surface of the second electrode.

4. 4. The MRAM device of claim 3, wherein the contact structure and the MTJ structure are both embedded in a second interconnect dielectric material layer.

5. 3. The MRAM device of claim 2, further comprising a contact structure disposed on the second electrode and contacting a surface of the second electrode.

6. 6. The MRAM device of claim 5, wherein the contact structure and the MTJ structure are both embedded in a second interconnect dielectric material layer.

7. 3. The MRAM device of claim 1, wherein the MTJ structure is a bottom-pinned MTJ structure.

8. The MRAM device of claim 1 or 2, wherein the MTJ structure is a top-pin MTJ structure.

9. The MRAM device of claim 1 or 2, wherein the magnetic via structure and the first electrode are both made of a magnetic material.

10. 3. The MRAM device of claim 1, wherein the magnetic via structure and the first electrode are both composed of a magnetic material, and the magnetic material of the magnetic via structure is compositionally the same as the magnetic material of the first electrode.

11. 3. The MRAM device of claim 1, wherein the magnetic via structure and the first electrode are both composed of a magnetic material, the magnetic material of the magnetic via structure being compositionally different from the magnetic material of the first electrode.

12. 3. The MRAM device of claim 1, wherein the magnetic via structure is made of a magnetic material and the first electrode is made of a non-magnetic but conductive material.

13. The MRAM device of claim 1 or 2, wherein the magnetic via structure has an aspect ratio greater than 2:

1.

14. The MRAM device of claim 1 or 2, wherein the magnetic reference layer has a magnetization vector direction that is the same as the magnetization vector direction of both the magnetic via structure and the magnetic free layer.

15. The MRAM device of claim 1 or 2, wherein the magnetic reference layer has a magnetization vector direction that is different from the magnetization vector directions of both the magnetic via structure and the magnetic free layer.

16. A non-volatile memory (NVM) array comprising a plurality of spaced apart magnetoresistive random access memory (MRAM) devices disposed on a substrate, the NVM array comprising: each MRAM device of the plurality of MRAM devices: a stack of a magnetic via structure disposed above a substrate and a first electrode on the magnetic via structure; a first interconnect dielectric material layer embedding both the magnetic via structure and the first electrode; a magnetic tunnel junction (MTJ) structure disposed on the first electrode of the stack, the MTJ structure comprising a magnetic reference layer, a magnetic free layer, and a tunnel barrier layer separating the magnetic reference layer from the magnetic free layer; a second electrode disposed on the MTJ structure; It is equipped with the magnetic via structure has a magnetic field that interacts with the magnetic free layer of the MTJ structure, aligning a direction of a magnetization vector of the magnetic free layer with a direction of a magnetization vector of the magnetic via structure, the direction of the magnetization vector of the magnetic via structure is random and dependent on an aspect ratio of the magnetic via structure, and reading the magnetization vector provides chip identification for a chip including the MRAM device. The NVM array.

17. A non-volatile memory (NVM) array comprising a plurality of spaced apart magnetoresistive random access memory (MRAM) devices disposed on a substrate, the NVM array comprising: each MRAM device of the plurality of MRAM devices: a stack of a first electrode disposed above a substrate and a magnetic via structure on the first electrode; a first interconnect dielectric material layer embedding both the first electrode and the magnetic via structure; a magnetic tunnel junction (MTJ) structure disposed on the magnetic via structure of the stack, the MTJ structure comprising a magnetic reference layer, a magnetic free layer, and a tunnel barrier layer separating the magnetic reference layer from the magnetic free layer; a second electrode disposed on the MTJ structure; It is equipped with the magnetic via structure has a magnetic field that interacts with the magnetic free layer of the MTJ structure, aligning a direction of a magnetization vector of the magnetic free layer with a direction of a magnetization vector of the magnetic via structure, the direction of the magnetization vector of the magnetic via structure is random and dependent on an aspect ratio of the magnetic via structure, and reading the magnetization vector provides chip identification for a chip including the MRAM device. The NVM array.

18. 18. The NVM array of claim 16 or 17, wherein the magnetic reference layer of a first set of MRAM devices has a magnetization vector direction that is the same as the magnetization of both the magnetic via structure and the magnetic free layer in the first set of MRAM devices, and the magnetic reference layer of a second set of MRAM devices has a magnetization vector direction that is different from the magnetization vector direction of both the magnetic via structure and the magnetic free layer in the second set of MRAM devices.

19. The NVM array of claim 16 or 17, wherein the magnetic reference layer has a magnetization vector direction that is the same as a magnetization vector direction of both the magnetic via structure and the magnetic free layer.

20. The NVM array of claim 16 or 17, wherein the magnetic reference layer has a magnetization vector direction that is different from the magnetization vector directions of both the magnetic via structure and the magnetic free layer.

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