Resistive random access memory and preparation method thereof
By introducing a strain structure into the resistive switching memory (RSM), the migration and aggregation of oxygen vacancies are regulated, solving the durability and retention problems of the RSM. This enables a more stable formation and breakage process of conductive filaments, improving the reliability and lifespan of the device.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-04-07
AI Technical Summary
Existing resistive switching memories (RSMs) face hard breakdown caused by oxygen vacancy accumulation and high resistance drift caused by oxygen ion recombination during long-term cyclic operation, affecting device durability and retention.
Introducing a strain structure into a resistive switching memory (RSM) applies dynamic stress to the resistive switching layer through deformation of the strain structure, thereby regulating the migration and aggregation of oxygen vacancies, forming stable conductive filaments, reducing the risk of oxygen ions entering the resistive switching layer, and improving the durability and retention of the device.
By introducing strain structures, the position of the conductive filaments is stabilized, the oxygen vacancy concentration gradient is improved, the durability and retention of the resistive switching memory are enhanced, and the formation and reset voltages are reduced.
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Figure CN121815955A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of memory technology, and more specifically, to a resistive random access memory and its fabrication method. Background Technology
[0002] With the rapid development of information technology, emerging application scenarios such as big data, artificial intelligence, the Internet of Things, edge computing, and dedicated hardware acceleration have placed higher demands on storage systems. Especially in the field of non-volatile memory, there is an urgent need for new storage technologies that combine high storage density, high-speed read / write capabilities, low power consumption, and good reliability. Resistive Random Access Memory (RRAM), as a novel non-volatile memory technology based on the resistance switching effect, is considered a strong candidate for next-generation memory due to its advantages such as simple structure, high miniaturization, fast read / write speed, low power consumption, good compatibility with CMOS processes, and support for 3D integration and in-memory computing. The basic working mechanism of RRAM is that under the action of an external electric field, oxygen vacancies migrate, accumulate, or disperse within the resistive switching layer, thereby forming or breaking conductive filaments, achieving reversible switching between high-resistivity and low-resistivity states, corresponding to storing data "0" and "1" respectively.
[0003] In practical array applications, to avoid crosstalk and achieve random access, a 1T1R (One Transistor One RRAM) structure is often used, where each memory cell consists of a gating transistor connected in series with an RRAM device. This structure effectively isolates unselected cells through transistors, significantly improving the addressability and reliability of the array. However, RRAM still faces severe reliability challenges during long-term cyclic operation: on the one hand, during repeated Set / Reset operations, oxygen vacancies may accumulate excessively in local areas, leading to uncontrolled growth of conductive filaments and causing hard breakdown; on the other hand, during the Reset process, if oxygen ions and oxygen vacancies completely recombine, it may cause the high-resistivity resistance value to drift, resulting in a smaller read window or even failure, leading to insufficient durability and retention between devices. Summary of the Invention
[0004] The purpose of this application is to provide a resistive switching memory and a method for fabricating the same, which can improve the durability and retention of the resistive switching memory.
[0005] The embodiments of this application are implemented as follows: A first aspect of this application provides a resistive switching memory, including a top electrode, a bottom electrode, and a resistive switching layer and a strain structure disposed between the top electrode and the bottom electrode. When the resistive switching memory is written, the strain structure deforms and forms compressive stress on the resistive switching layer, causing oxygen vacancies in the resistive switching layer to accumulate towards the center of the resistive switching layer. When the resistive switching memory is reset, the strain structure deforms and forms tensile stress on the resistive switching layer, causing the lattice spacing of the resistive switching layer to increase, and the oxygen vacancies to move towards the outer periphery of the resistive switching layer, making it easier for oxygen ions to enter the resistive switching layer and combine with oxygen vacancies.
[0006] As one possible implementation, the strain structure includes a cover layer and a piezoelectric ring disposed on the outer periphery of the cover layer.
[0007] As one possible implementation, the strain structure is disposed on the side near the top electrode or the side near the bottom electrode.
[0008] As one possible implementation, when the strain structure is positioned on the side near the bottom electrode, the cover layer extends to the upper surface of the piezoelectric ring.
[0009] As one possible implementation, the height of the piezoelectric ring is greater than the height of the capping layer so that the center of the resistive switching layer protrudes downwards.
[0010] As one possible implementation, the resistive switching layer includes two layers, and the strain structure includes a piezoelectric layer disposed between the two resistive switching layers.
[0011] As one possible implementation, the strain structure includes a piezoelectric ring disposed on the outer periphery of the resistive switching layer and a capping layer located on the upper surface of the resistive switching layer and the piezoelectric ring.
[0012] As one possible implementation, the resistive switching layer is flush with the surface of the piezoelectric ring.
[0013] As one possible implementation, an oxygen ion storage layer is also provided on the side of the top electrode near the bottom electrode.
[0014] A second aspect of this application provides a method for fabricating a resistive switching memory (RSM), comprising: providing a substrate, the substrate including a bottom electrode; forming a resistive switching layer and a strained structure intermediate on the bottom electrode; forming a top electrode on the intermediate to form the RSM; wherein during writing to the RSM, the strained structure deforms to form compressive stress on the resistive switching layer, causing oxygen vacancies in the resistive switching layer to accumulate towards the center of the resistive switching layer; during resetting of the RSM, the strained structure deforms to form tensile stress on the resistive switching layer, causing the lattice spacing of the resistive switching layer to increase, and oxygen vacancies to move towards the outer periphery of the resistive switching layer, making it easier for oxygen ions to enter the resistive switching layer and combine with oxygen vacancies.
[0015] The beneficial effects of the embodiments of this application include: The resistive switching memory (RSM) provided in this application includes a top electrode, a bottom electrode, and a resistive switching layer and a strain structure disposed between the top and bottom electrodes. During writing to the RSM, the strain structure deforms, creating compressive stress on the resistive switching layer, causing oxygen vacancies in the layer to accumulate towards the center. During reset, the strain structure deforms, creating tensile stress on the resistive switching layer, increasing the lattice spacing and causing oxygen vacancies to move towards the periphery, making it easier for oxygen ions to enter the layer and combine with the vacancies. This embodiment of the RSM introduces a strain structure between the top and bottom electrodes. The deformation of the strain structure applies dynamic stress to the resistive switching layer, which guides the directional migration and accumulation of oxygen vacancies along a specific path, effectively controlling the formation and breakage process of the conductive filaments and reducing the formation voltage and reset / set voltage. Specifically, the strain structure stabilizes the position of the conductive filaments, repeatedly improving the oxygen vacancy concentration gradient to cause oxygen vacancies to continuously accumulate towards the center, thus improving the durability of the RSM. Furthermore, the strain structure of this application reduces the lattice spacing of the resistive switching layer, making it more difficult for oxygen ions to enter the resistive switching layer. This reduces the risk of free oxygen and oxygen vacancy binding when the resistive switching memory is maintained in a low-resistivity state for a long time, thus improving the retention of the resistive switching memory. Therefore, the resistive switching memory of the embodiments of this application can improve the durability and retention of the resistive switching memory. Attached Figure Description
[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is one of the structural schematic diagrams of the resistive random access memory provided in the embodiments of this application; Figure 2 This is a second schematic diagram of the resistive random access memory provided in the embodiments of this application; Figure 3 This is the third schematic diagram of the resistive random access memory provided in the embodiments of this application; Figure 4 This is the fourth schematic diagram of the resistive random access memory provided in the embodiments of this application; Figure 5 Fifth schematic diagram of the resistive random access memory provided in the embodiments of this application; Figure 6 This is the sixth schematic diagram of the resistive random access memory provided in the embodiments of this application; Figure 7 This is one of the operating state diagrams of the resistive random access memory provided in the embodiments of this application; Figure 8 for Figure 7 Atomic arrangement diagram at point A; Figure 9 This is the second working state diagram of the resistive random access memory provided in the embodiments of this application; Figure 10 for Figure 9 Atomic arrangement diagram at point B; Figure 11 This is a flowchart of the resistive random access memory fabrication method provided in the embodiments of this application; Figure 12 This is one of the state diagrams of the resistive switching memory fabrication method provided in the embodiments of this application; Figure 13 This is the second state diagram of the resistive switching memory fabrication method provided in the embodiments of this application; Figure 14 This is the third state diagram of the resistive random access memory fabrication method provided in the embodiments of this application; Figure 15 This is the fourth state diagram of the resistive random access memory fabrication method provided in the embodiments of this application; Figure 16 This is the fifth state diagram of the resistive switching memory fabrication method provided in the embodiments of this application.
[0018] Icons: 100-Resistive switching memory; 110-Top electrode; 120-Bottom electrode; 130-Resistive switching layer; 140-Strained structure; 141-Capping layer; 142-Piezoelectric ring; 143-Piezoelectric layer; 150-Oxygen ion storage layer; 160-Substrate; 161-Wiring layer; 162-Via; 163-Dielectric layer. Detailed Implementation
[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are only some embodiments of this application, not all embodiments. Similar reference numerals and letters in the following drawings indicate similar items. Once an item is defined in one drawing, it does not need to be further defined in other drawings.
[0020] The terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and should not be construed as limiting this application. The terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0021] Unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to connections within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0022] In existing RRAM technologies, oxygen vacancies migrate to form conductive filaments driven by an electric field. However, this process is highly random, especially at the nanoscale. Local defects, grain boundaries, or interface inhomogeneities can cause excessive concentration of oxygen vacancies in certain regions, leading to excessively thick filaments or even short circuits. Furthermore, during the reset process, if oxygen ions completely fill the vacancies, the resistive switching layer may recover to a state close to its intrinsic high resistance. However, due to material aging or interface degradation, the high resistance state (HRS) will gradually decrease after multiple cycles, while the low resistance state (LRS) may increase. This results in a shrinking readout window (LRS / HRS ratio), affecting device stability and durability.
[0023] Please refer to the reference. Figures 1 to 6 This application provides a resistive switching memory 100, including a top electrode 110, a bottom electrode 120, and a resistive switching layer 130 and a strain structure 140 disposed between the top electrode 110 and the bottom electrode 120. When the resistive switching memory 100 is written, the strain structure 140 deforms and forms compressive stress on the resistive switching layer 130, causing oxygen vacancies in the resistive switching layer 130 to accumulate towards the center of the resistive switching layer 130. When the resistive switching memory 100 is reset, the strain structure 140 deforms and forms tensile stress on the resistive switching layer 130, causing the lattice of the resistive switching layer 130 to become larger, oxygen vacancies to move towards the top electrode 110, and oxygen ions to more easily enter the resistive switching layer 130 and combine with oxygen vacancies.
[0024] In this embodiment of the application, to control the position of the conductive wire, a resistive switching layer 130 and a strain structure 140 are provided between the top electrode 110 and the bottom electrode 120, wherein the top electrode 110 and the bottom electrode 120 are arranged opposite to each other. Specifically, as shown in the example... Figure 1 As shown, the resistive switching memory 100 of this application embodiment consists of a bottom electrode 120, a strain structure 140, a resistive switching layer 130, and a top electrode 110, arranged from bottom to top.
[0025] The strain structure 140 deforms after the strain condition is met, thereby generating pressure or tension on the periphery, that is, compressing or stretching the resistive switching layer 130, causing the lattice of the resistive switching layer 130 to be compressed or expanded, changing the migration barrier and diffusion path of oxygen vacancies in the resistive switching layer 130, thereby controlling the formation or breakage of conductive filaments.
[0026] Specifically, with Figure 1 For example, the strain structure 140 uses a piezoelectric material. When the top electrode 110 is connected to the positive terminal and the bottom electrode 120 is connected to the negative terminal, i.e., when a positive voltage is applied, i.e. when the resistive switching memory 100 is written to (set), such as... Figure 7 and Figure 8 As shown, the strain structure 140 and the resistive switching layer 130 located between the top electrode 110 and the bottom electrode 120 are both in the electric field formed by the top electrode 110 and the bottom electrode 120. At this time, under the action of the electric field, the resistive switching layer 130 drives oxygen vacancies to migrate to the low barrier region, realizing the writing process. At the same time, under the action of the electric field, the piezoelectric material triggers the inverse piezoelectric effect, causing the piezoelectric material to expand along the thickness direction, thereby squeezing the resistive switching layer 130, making the lattice spacing of the outer periphery of the resistive switching layer 130 smaller, increasing the oxygen vacancy migration barrier at the outer periphery, and making the oxygen vacancy migration barrier at the center lower. The stress gradient guides the oxygen vacancy to directionally accumulate along the high stress region, forming a single conductive filament with a fixed position and uniform size, avoiding the growth of multiple filaments or dendrites.
[0027] Conversely, such as Figure 9 and Figure 10 As shown, when the top electrode 110 is connected to the negative electrode and the bottom electrode 120 is connected to the positive electrode, i.e., when the reverse voltage is applied, i.e. when the resistive switching memory 100 is reset, the strain structure 140 and the resistive switching layer 130 located between the top electrode 110 and the bottom electrode 120 are both in the electric field formed by the top electrode 110 and the bottom electrode 120, driving oxygen ions to migrate back to the bottom electrode 120. The bottom electrode 120 acts as the positive electrode to realize the reset process. At the same time, under the action of the electric field, the piezoelectric material triggers the inverse piezoelectric effect, causing the piezoelectric material to shrink along the thickness direction, thereby pulling the resistive switching layer 130, making the lattice spacing of the resistive switching layer 130 larger, and the oxygen vacancies move to the outer periphery of the resistive switching layer. Oxygen ions can easily enter the resistive switching layer 130 and combine with the oxygen vacancies, realizing the breakage of the conductive filament.
[0028] In summary, the resistive switching memory 100 of this application introduces a strain structure 140 between the top electrode 110 and the bottom electrode 120. The strain structure 140 deforms, thereby applying dynamic stress to the resistive switching layer 130. This stress guides oxygen vacancies to migrate and accumulate along a specific path, effectively controlling the formation and breakage process of the conductive filaments. Specifically, the strain structure 140 stabilizes the position of the conductive filaments, repeatedly improving the oxygen vacancy concentration gradient to cause oxygen vacancies to continuously accumulate towards the center, thus enhancing the durability of the resistive switching memory 100. Furthermore, the strain structure 140 of this application reduces the lattice spacing of the resistive switching layer 130, making it more difficult for oxygen ions to enter the resistive switching layer 130. This reduces the risk of free oxygen and oxygen vacancies combining when the resistive switching memory 100 remains in a low-resistivity state for a long time, improving the retention of the resistive switching memory 100. Therefore, the resistive switching memory 100 of this application can improve the durability and retention of the resistive switching memory 100.
[0029] In addition, the introduction of the strain structure 140 in this embodiment can promote the generation and movement of oxygen vacancies, thereby reducing the formation voltage and reset voltage of the resistive switching memory 100.
[0030] The resistive switching layer 130 is an oxide containing oxygen vacancies, such as HfO2, ZrO2, Ta2O5, or TiO2. The top electrode 110 and bottom electrode 120 are made of any of the following materials: inert metal materials, inert metal alloys, metallic materials, and metallic compound materials. Inert metal materials include Pt, Pd, and Ir; inert metal alloys are alloys of Pt, Pd, and Ir; metallic materials include Ta, Hf, Ti, Zr, W, Ru, and Al; and metallic compound materials include any of the following: TiN, TaN, and Poly-Si. Those skilled in the art can select the appropriate materials based on the specific circumstances.
[0031] It should be noted that the resistive random access memory 100 in this embodiment is a storage unit in a memory. In practical applications, a resistive random access memory 100 includes multiple such... Figure 1 The memory cells shown typically have a dielectric layer 163 and a substrate 160 disposed on the outer periphery of each cell to isolate adjacent memory cells, such as... Figure 2 As shown, a wiring layer 161 is formed in the substrate 160, and the wiring layer 161 contacts the bottom electrode 120 through the via 162 to supply power to the bottom electrode 120.
[0032] Optional, such as Figure 1 , Figure 2 , Figure 4 and Figure 6 As shown, the strain structure 140 includes a cover layer 141 and a piezoelectric ring 142 disposed on the outer periphery of the cover layer 141.
[0033] The strain structure 140 consists of a capping layer 141 and a piezoelectric ring 142 surrounding the outer periphery of the capping layer 141. The capping layer 141 is an oxide layer with conductive properties, located in the central region of the resistive switching layer 130, used to define the effective switching area and transmit stress; the piezoelectric ring 142 is made of a material with inverse piezoelectric effect and is located around the capping layer 141. When a voltage is applied between the top electrode 110 and the bottom electrode 120, the piezoelectric ring 142 undergoes controllable deformation due to the electric field, compressing the outer periphery of the resistive switching layer 130, while the capping layer 141 remains unchanged. This allows for the regulation of the migration and accumulation behavior of oxygen vacancies within the resistive switching layer 130 corresponding to the capping layer 141.
[0034] During the Set operation, a positive voltage is applied. This positive voltage drives oxygen vacancies to migrate towards the bottom electrode 120 and simultaneously generates compressive stress in the piezoelectric ring 142. This stress is then focused onto the outer periphery of the resistive switching layer 130 through the capping layer 141. This compressive stress lowers the migration barrier of oxygen vacancies within the resistive switching layer 130 and guides them to form a single, stable conductive filament directly above or below the capping layer 141, preventing edge nucleation or competition among multiple filaments.
[0035] The Reset operation applies a reverse voltage, introducing tensile stress into the resistive transformer. This stress promotes lattice expansion, which facilitates oxygen ion migration and drives more residual oxygen vacancies to move towards the top electrode 110, assisting in the controlled fracture of the conductive filament. Because the capping layer 141 limits the stress range, it avoids the retention of random vacancies in the edge region, making the recovery from the high-resistivity state more stable.
[0036] The piezoelectric ring 142 and the capping layer 141 achieve stress spatial focusing, suppressing the random growth of conductive filaments, significantly reducing hard breakdown, significantly extending cycle life, and improving durability. Controllable residual stress stabilizes the high-resistivity state, effectively suppressing resistance drift under high temperatures or long-term storage.
[0037] Among them, the piezoelectric ring 142 can be made of piezoelectric materials, such as barium titanate, lead zirconate titanate, zinc oxide, aluminum nitride, etc.
[0038] As one possible implementation, the strain structure 140 is disposed on the side near the top electrode 110 or on the side near the bottom electrode 120.
[0039] Specifically, such as Figure 1 As shown, the strain structure 140 is disposed on the side near the bottom electrode 120; as Figure 6 As shown, the strain structure 140 is disposed on the side near the top electrode 110. Those skilled in the art can configure it according to actual conditions.
[0040] The strain structure 140 is close to a certain electrode, which can concentrate the stress on the interface, guide the filament to nucleate and break in a preset area, avoid random distribution, and improve the repeatability of switching behavior.
[0041] The adjustable position of the strain structure 140 makes the resistive switching memory 100 of this application more adaptable.
[0042] Optional, such as Figure 4 As shown, when the strain structure 140 is disposed on the side near the bottom electrode 120, the cover layer 141 extends to the upper surface of the piezoelectric ring 142.
[0043] The capping layer 141 serves as a rigid stress transmission medium, which homogenizes the local deformation of the piezoelectric ring 142 and focuses the transmission to the center of the resistive switching layer 130; and defines the area where the conductive filaments are formed, preventing edge leakage or asymmetric growth.
[0044] When the piezoelectric ring 142 is excited by an electric field, it undergoes axial compressive deformation (bulging upwards), pushing the capping layer 141 above it upwards to compress the bottom of the resistive switching layer 130, forming local compressive stress in the resistive switching layer 130 near the bottom electrode 120. This compressive stress increases the oxygen vacancy migration barrier and establishes a stress gradient upwards from the bottom electrode 120, guiding oxygen vacancies to accumulate in the region directly above the capping layer 141, forming a stable conductive filament that starts from the bottom electrode 120 and grows vertically upwards.
[0045] The cover layer 141 extends to the upper surface of the piezoelectric ring 142 to ensure seamless deformation transmission, avoid stress leakage or edge concentration, and achieve high-fidelity stress loading in the central area.
[0046] As an feasible approach, such as Figure 4 As shown, the height of the piezoelectric ring 142 is greater than the height of the capping layer 141 so that the center of the resistive switching layer 130 protrudes downward.
[0047] The height of the piezoelectric ring 142 is greater than the height of the capping layer 141, thus forming a stepped support profile in the device stack structure. Since the capping layer 141 is located in the central region and has a lower height, while the piezoelectric ring 142 surrounding it is higher, when a continuous resistive switching layer 130 and a top electrode 110 are deposited on top of it, the resistive switching layer 130 will naturally be recessed downward in the central region due to the difference in support height below (i.e., "protruding downward"), forming a predetermined curved surface or a local stress concentration area.
[0048] When a forward voltage is applied, the piezoelectric ring 142 exerts a certain compressive stress on the resistive switching layer 130 located at the center due to the inverse piezoelectric effect. This further tightens or compresses the central region of the resistive switching layer 130, enhancing the local electric field. Under the combined action of the electric field and the pre-existing stress gradient, oxygen vacancies preferentially migrate and accumulate towards the thinnest and most stressed central region, forming a single, vertical conductive filament. Conversely, when a reverse voltage is applied, oxygen ions migrate back and preferentially break the filament at the weakest point in the center. The concave morphology helps limit the vacancy diffusion range and improves the consistency of resetting.
[0049] Optional, such as Figure 3 As shown, the resistive switching layer 130 includes two layers, and the strain structure 140 includes a piezoelectric layer 143 disposed between the two resistive switching layers 130.
[0050] When a positive field is applied, the electric field drives oxygen vacancies to migrate downwards from the upper resistive switching layer 130. At the same time, the piezoelectric layer 143 is compressed in the thickness direction due to the electric field, applying compressive stress to the upper and lower resistive switching layers 130. This compressive stress causes lattice distortion in the two layers of resistive switching materials, increases the oxygen vacancy migration barrier, and forms a stress concentration region near the piezoelectric layer 143. Oxygen vacancies are guided to accumulate near the interface of the piezoelectric layer 143 / resistive switching layer 130, which may form continuous conductive filaments that penetrate the two layers, or form coupled conductive channels in the two layers respectively, achieving low-resistance conduction.
[0051] When a reverse voltage is applied, the deformation direction of the piezoelectric layer 143 is reversed; the tensile stress causes the lattice expansion of the resistive switching layer 130, enhances the driving force for oxygen ion migration, and pushes oxygen vacancies away from the interface of the piezoelectric layer 143 and towards their respective neighboring electrodes; since the piezoelectric layer 143 is located in the middle as a stress source, it can simultaneously cut off the conductive paths in the upper and lower resistive switching layers 130, achieving a more thorough reset; the double-layer structure also provides a redundant blocking mechanism, so that even if one layer is not completely disconnected, the other layer can still maintain a high-resistivity state, improving reliability.
[0052] The materials and oxygen vacancy concentrations of the two resistive switching layers 130 are not limited. Those skilled in the art can set them according to the actual situation. The materials can be the same or different; the concentrations can be the same or different.
[0053] As an feasible approach, such as Figure 5 As shown, the strain structure 140 includes a piezoelectric ring 142 disposed on the outer periphery of the resistive switching layer 130 and a capping layer 141 located on the upper surface of the resistive switching layer 130 and the piezoelectric ring 142.
[0054] By placing the piezoelectric ring 142 on the outer periphery of the resistive switching layer 130, when the piezoelectric ring 142 deforms, it can act on the entire outer periphery of the resistive switching layer 130, which can better enable oxygen vacancies to accumulate towards the center of the resistive switching layer 130.
[0055] Optional, such as Figure 5 As shown, the resistive switching layer 130 is flush with the surface of the piezoelectric ring 142.
[0056] In the fabrication process of resistive switching memory 100, the capping layer 141 is usually deposited. The flat surface avoids poor coverage of the capping layer 141 due to height difference, and avoids the risk of stress concentration or film breakage caused by stacking.
[0057] As one possible approach, an oxygen ion storage layer 150 is also provided on the side of the top electrode 110 near the bottom electrode 120.
[0058] The oxygen ion storage layer 150 is typically made of a dense, chemically inert material with an extremely low oxygen diffusion coefficient, such as TiN, TaN, Ru, Ir, Pt, or nitrides / carbides. Its core function is to suppress the reverse diffusion of oxygen ions from the top electrode 110 to the resistive switching layer 130 during device operation, or to prevent the infiltration of ambient oxygen, thereby stabilizing the oxygen vacancy concentration distribution of the resistive switching layer 130.
[0059] This application embodiment also provides a method for fabricating a resistive switching memory 100, used to fabricate the aforementioned resistive switching memory 100, such as... Figure 11 As shown, it includes: S100: As Figure 12 As shown, a substrate is provided, the substrate including a bottom electrode 120; Among them, such as Figure 12 As shown, the substrate includes a substrate 160 and a wiring layer 161 disposed within the substrate 160. A via 162 is also formed on the wiring layer 161. A cover layer is used to isolate the bottom electrode 120 from the substrate 160 around the via 162 to prevent electrical leakage.
[0060] S200: such as Figure 12 , Figure 13 , Figure 14 and Figure 15 As shown, a resistive switching layer 130 and a strain structure 140 are formed on the bottom electrode 120 to form an intermediate. like Figure 12 As shown, a dielectric material is disposed on the bottom electrode 120, and as shown in 13, the dielectric material is etched to form a capping layer 141; further as shown... Figure 14 As shown, a piezoelectric material is deposited on the capping layer 141 and ground flat to form a piezoelectric ring 142. A resistive switching layer 130 and an oxygen ion storage layer 150 are sequentially formed on the upper surfaces of the piezoelectric ring 142 and the capping layer 141, thus forming an intermediate.
[0061] S300: such as Figure 15 As shown, a top electrode 110 is formed on the intermediate body to form a resistive switching memory 100. When the resistive switching memory 100 is written, the strain structure 140 deforms and forms compressive stress on the resistive switching layer 130, causing oxygen vacancies in the resistive switching layer 130 to accumulate towards the center of the resistive switching layer 130. When the resistive switching memory 100 is reset, the strain structure 140 deforms and forms tensile stress on the resistive switching layer 130, causing oxygen vacancies in the resistive switching layer 130 to move towards the outer periphery of the resistive switching layer 130.
[0062] After forming the top electrode 110, it can be as follows: Figure 16 As shown, etching is performed from top to bottom until the substrate is exposed, and then a dielectric layer 163 is applied to encapsulate the structure.
[0063] It should be noted that the embodiments of this application are based on... Figure 1The fabrication method of the resistive switching memory 100 shown is illustrated as an example. Those skilled in the art can set up the fabrication method of the resistive switching memory 100 according to the specific structure of the resistive switching layer 130 and the strain structure 140.
[0064] The above description is merely an optional embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
[0065] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.
Claims
1. A resistive random access memory, characterized in that, The resistive switching memory includes a top electrode, a bottom electrode, and a resistive switching layer and a strain structure disposed between the top electrode and the bottom electrode. When the resistive switching memory is written, the strain structure deforms and forms compressive stress on the resistive switching layer, causing oxygen vacancies in the resistive switching layer to accumulate towards the center of the resistive switching layer. When the resistive switching memory is reset, the strain structure deforms and forms tensile stress on the resistive switching layer, causing the lattice of the resistive switching layer to become larger, oxygen vacancies to move towards the outer periphery of the resistive switching layer, and oxygen ions to more easily enter the resistive switching layer and combine with oxygen vacancies.
2. The resistive random access memory according to claim 1, characterized in that, The strain structure includes a cover layer and a piezoelectric ring disposed on the outer periphery of the cover layer.
3. The resistive random access memory according to claim 2, characterized in that, The strain structure is disposed on the side near the top electrode or on the side near the bottom electrode.
4. The resistive random access memory according to claim 3, characterized in that, When the strain structure is disposed on the side close to the bottom electrode, the cover layer extends to the upper surface of the piezoelectric ring.
5. The resistive random access memory according to claim 4, characterized in that, The height of the piezoelectric ring is greater than the height of the capping layer so that the center of the resistive switching layer protrudes downwards.
6. The resistive random access memory according to claim 1, characterized in that, The resistive switching layer comprises two layers, and the strain structure includes a piezoelectric layer disposed between the two resistive switching layers.
7. The resistive random access memory according to claim 1, characterized in that, The strain structure includes a piezoelectric ring disposed on the outer periphery of the resistive switching layer and a capping layer located on the upper surface of the resistive switching layer and the piezoelectric ring.
8. The resistive random access memory according to claim 7, characterized in that, The resistive switching layer is flush with the surface of the piezoelectric ring.
9. The resistive random access memory according to claim 1, characterized in that, An oxygen ion storage layer is also provided on the side of the top electrode near the bottom electrode.
10. A method for fabricating a resistive random access memory (RANM), characterized in that, For fabricating a resistive switching memory as described in any one of claims 1 to 9, comprising: A substrate is provided, the substrate including a bottom electrode; A resistive switching layer and a strained structure are formed on the bottom electrode to form an intermediate. A top electrode is formed on the intermediate body. The top electrode, bottom electrode, and intermediate body constitute a resistive switching memory. When the resistive switching memory is written, the strain structure deforms and forms compressive stress on the resistive switching layer, causing oxygen vacancies in the resistive switching layer to accumulate towards the center of the resistive switching layer. When the resistive switching memory is reset, the strain structure deforms and forms tensile stress on the resistive switching layer, causing the lattice spacing of the resistive switching layer to increase, and oxygen vacancies to move towards the outer periphery of the resistive switching layer, making it easier for oxygen ions to enter the resistive switching layer and combine with oxygen vacancies.