Storage array and forming method thereof
By setting a storage layer in a three-dimensional structure between the first and second conductive layers in the memory, the problems of low storage density and leakage path are solved, thereby improving storage density and controlling leakage path.
Patent Information
- Application Number
- CN202511093070.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-05
- Publication Date
- 2025-11-04
AI Technical Summary
Existing memory has low storage density and leakage paths that can lead to erroneous reads.
By placing the storage layer between at least one first conductive layer and at least one second conductive layer along a second direction, and extending the storage layer along a first direction, a three-dimensional structure of the storage cell is achieved. The switching device is located on one side of the first conductive layer and the second conductive layer along the first direction to control the leakage path and save storage area.
It effectively increases storage density while controlling leakage paths and reducing the occupancy of storage areas by switching devices, thereby increasing storage density.
Smart Images
Figure CN120897463A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor manufacturing, and in particular to a memory array and a method for forming the same. Background Technology
[0002] In recent years, resistive random access memory (RRAM), phase-change memory (PCM), and ferroelectric memory have been widely studied due to their characteristics such as low latency, balanced read / write time, long lifespan, low power consumption, and good radiation resistance, as well as the fact that they currently have no physical limitations and are easy to implement in high-density memory applications.
[0003] Among all resistive random access memories, phase change memories, or ferroelectric memories, a memory cell consisting of one switching device and one storage element has advantages such as small unit area, easy integration, and ease of implementing high-performance computing.
[0004] However, the storage density of existing memory is relatively low. Summary of the Invention
[0005] The problem addressed by this invention is how to increase the storage density of a memory.
[0006] To address the above problems, the present invention provides a storage array, comprising:
[0007] At least one switching device; at least one first conductive layer, the at least one first conductive layer being located on one side of the at least one switching device along a first direction, the at least one first conductive layer being electrically connected to one end of the at least one switching device in a one-to-one correspondence; at least one second conductive layer, the at least one second conductive layer being located on one side of the at least one first conductive layer along a second direction, the at least one second conductive layer extending along the second direction, wherein the second direction intersects the first direction; a storage layer, the storage layer being located between the at least one second conductive layer and the at least one first conductive layer.
[0008] Accordingly, the present invention also provides a method for forming a storage array, comprising:
[0009] A substrate is provided, with a direction perpendicular to the surface of the substrate being a first direction; at least one switching device is formed on the substrate; a storage layer is formed on the at least one switching device; at least one first conductive layer and at least one second conductive layer are formed on the at least one switching device, the at least one first conductive layer is electrically connected to one end of the at least one switching device, the at least one first conductive layer and the at least one second conductive layer are disposed along a second direction, and the storage layer is located between the at least one first conductive layer and the at least one second conductive layer, wherein the second direction intersects the first direction.
[0010] Compared with the prior art, the technical solution of the present invention has the following advantages:
[0011] In this invention, at least one first conductive layer is located on one side of at least one switching device along a first direction; a storage layer electrically connected to at least one first conductive layer is located on one side of at least one first conductive layer along a second direction intersecting the first direction; at least one second conductive layer is located on the side of the storage layer away from at least one first conductive layer along the second direction, and the at least one second conductive layer is electrically connected to the storage layer. By placing the storage layer between at least one first conductive layer and at least one second conductive layer along the second direction, extending the storage layer along the first direction and extending the first conductive layer along the second direction, a three-dimensional structure of the storage cell is achieved, which can greatly improve the storage density; moreover, by placing at least one switching device on one side of at least one first conductive layer and at least one second conductive layer along the first direction, leakage paths are controlled while effectively saving the area occupied by the switching device in the storage area, which can effectively improve the storage density. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of a storage array in a memory.
[0013] Figures 2 to 29 These are schematic diagrams illustrating the various steps of some embodiments of the method for forming a storage array according to the present invention;
[0014] Figure 30 This is a three-dimensional structural schematic diagram of some other embodiments of the storage array of the present invention. Detailed Implementation
[0015] As is known from the background art, existing memory technologies suffer from relatively low storage density. This paper analyzes the reasons for this low storage density by referring to a schematic diagram of a memory array structure.
[0016] refer to Figure 1 The diagram shows a schematic of the structure of a storage array in a memory.
[0017] In the memory array, word lines (wl) and bit lines are arranged in a crossbar structure. Specifically, in the xy plane, bit lines (bl) extend along the y-direction, and multiple bit lines (bl) are arranged parallel to each other along the x-direction; in the xy plane, word lines (wl) extend along the x-direction, and multiple word lines (wl) are arranged parallel to each other along the y-direction. Multiple word lines (wl) are located above multiple bit lines (bl). The memory layer is located between the bit lines (bl) and word lines (wl), at their overlapping position.
[0018] like Figure 1 As shown, when memory cell 1 is in the off state, the adjacent memory cells 2, 3, and 4 are all in the on state. When reading memory cell 1, there will be a clear leakage path (such as...). Figure 1(As shown by the red solid arrow in the middle), which can lead to misreading operations; therefore, for each storage unit, a corresponding switching device needs to be set up to form a 1T1R structure.
[0019] The switching devices added to control leakage paths reduce the area of the storage region, resulting in a decrease in storage density.
[0020] To address the technical problem, this invention provides a storage array and a method for forming the same. By disposing a storage layer between at least one first conductive layer and at least one second conductive layer along a second direction, extending the storage layer along a first direction and the first conductive layer along the second direction, a three-dimensional structure of the storage cell is achieved, which can greatly improve storage density. Furthermore, at least one switching device is located on one side of at least one first conductive layer and at least one second conductive layer along the first direction, which effectively saves the area occupied by the switching device in the storage region while controlling leakage current paths, thus effectively improving storage density.
[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0022] refer to Figures 2 to 29 The diagram shows structural schematics of various steps in some embodiments of the method for forming a storage array according to the present invention.
[0023] First, a substrate is provided, with the direction perpendicular to the substrate surface being the first direction.
[0024] The substrate is used to provide mechanical support and a process platform.
[0025] Specifically, the substrate material can be selected from monocrystalline silicon, polycrystalline silicon, or amorphous silicon. In other embodiments, the substrate material can also be selected from silicon, germanium, gallium arsenide, or silicon-germanium compounds; the substrate can also be selected from materials having an epitaxial layer or a silicon-on-epitaxy layer structure; the substrate can also be other semiconductor materials. In some embodiments of the present invention, the substrate is a monocrystalline silicon substrate.
[0026] refer to Figure 2 and Figure 3 At least one switching device is formed on the substrate.
[0027] in, Figure 2 This is a top view of the intermediate structure in some embodiments of the method for forming the present invention. Figure 3 yes Figure 2 A schematic diagram of the cross-sectional structure along line A1A1.
[0028] Switching devices are used to control leakage paths in the memory array to prevent erroneous read operations.
[0029] In some embodiments of the present invention, the step of forming at least one switching device on a substrate includes: forming at least one vertical channel switching device on the substrate, i.e., the switching device is a vertical channel switching device, and the channel of the switching device extends along a first direction. The channel of the switching device is perpendicular to the substrate surface. By configuring the switching device as a channel switching device, the area occupied by the switching device on the substrate can be effectively reduced, and the wafer area can be effectively accommodated.
[0030] In some embodiments, the step of forming at least one switching device on a substrate includes: forming a channel pillar extending along a first direction; and forming a fully enclosed gate structure circumferentially surrounding the channel pillar along the first direction. That is, the switching device includes: a channel pillar extending along the first direction; and a fully enclosed gate structure circumferentially surrounding the channel pillar along the first direction.
[0031] like Figure 2 and Figure 3 In some embodiments shown, the switching device 110 includes a channel post 111 and a fully enclosed gate structure 112. The channel post 111 extends along a first direction x. The fully enclosed gate structure circumferentially surrounds the channel post 111 in a plane perpendicular to the first direction x (yz plane).
[0032] It should be noted that, as Figure 2 and Figure 3 Some of the embodiments shown do not show a substrate.
[0033] In some embodiments of the present invention, the step of forming at least one switching device on a substrate includes: forming a plurality of switching devices arranged along a third direction on the substrate, wherein the third direction intersects with a first direction.
[0034] like Figure 2 and Figure 3 In some embodiments shown, a plurality of switching devices 110 are arranged along a third direction z, wherein the third direction z is perpendicular to the first direction x. The arrangement direction of the plurality of switching devices 110 is perpendicular to the channel direction of the switching devices 110.
[0035] Continue to refer to Figure 2 and Figure 3 In some embodiments of the present invention, the forming method further includes: forming a peripheral circuit on a substrate on one side of at least one switching device along a second direction.
[0036] Specifically, the peripheral circuitry includes one or more of a word line driver (WLD) and an input / output (I / O) structure. The peripheral circuitry is located on one side of at least one switching device along the second direction, which allows for full utilization of the material on one side of the at least one switching device along the second direction, effectively improving integration density. The second direction intersects with the first direction and also with a third direction.
[0037] like Figure 2 and Figure 3 In some embodiments shown, the peripheral circuit Peri and at least one switching device 110 are arranged along a second direction y, wherein the second direction y is perpendicular to the first direction x and perpendicular to the third direction z.
[0038] refer to Figure 4 In some embodiments of the present invention, the forming method further includes: after forming at least one switching device on the substrate, forming a third barrier layer on the at least one switching device.
[0039] in, Figure 4 The intermediate structure and the method of forming the present invention are shown in some embodiments. Figure 3 A cross-sectional structural diagram of the corresponding location.
[0040] The third barrier layer is used to achieve electrical isolation between the subsequent structure and the peripheral circuitry.
[0041] Specifically, the material of the third barrier layer includes, but is not limited to, silicon nitride insulating material. The step of forming the third barrier layer on the peripheral circuit and at least one switching device includes: determining the thickness of the third barrier layer based on the parasitic capacitance between the subsequent structure and the peripheral circuit. The thickness of the third barrier layer is in the range of 10 nm to 100 nm.
[0042] In some embodiments of the present invention, at least one switching device has a peripheral circuit formed on a substrate along one side of a second direction; the step of forming a third barrier layer on the at least one switching device includes forming a third barrier layer on the peripheral circuit and the at least one switching device. For example, the third barrier layer can be formed on the peripheral circuit and the at least one switching device by chemical vapor deposition, physical vapor deposition, and atomic layer deposition.
[0043] like Figure 4 In some embodiments shown, a third barrier layer 101 is located on the peripheral circuit Peri and at least one switching device 110. The third barrier layer 101 is located on the side of the peripheral circuit Peri and at least one switching device 110 away from the substrate along a first direction x.
[0044] refer to Figure 5 and Figure 6In some embodiments of the present invention, the forming method further includes: forming at least one switching device between at least one switching device, forming a sacrificial material on at least one switching device; forming a pre-formed trench in the sacrificial material, the pre-formed trench penetrating the sacrificial material along a first direction.
[0045] in, Figure 5 This is a top view of the intermediate structure in some embodiments of the method for forming the present invention. Figure 6 yes Figure 5 A schematic diagram of the cross-sectional structure along line A2A2.
[0046] The sacrificial material provides a good technological basis for the formation of subsequent structures.
[0047] Specifically, the step of forming a sacrificial material on at least one switching device includes: depositing a sacrificial material on at least one switching device; for example, the sacrificial material can be deposited on at least one switching device by means of chemical vapor deposition, physical vapor deposition and atomic layer deposition.
[0048] In some embodiments of this disclosure, the sacrificial material is made of a different material than the third barrier layer. Using different materials for the sacrificial material and the third barrier layer effectively reduces the impact of subsequent processes on the third barrier layer, effectively ensures the quality and thickness of the third barrier layer, and effectively guarantees its function of suppressing parasitic capacitance. Specifically, the sacrificial material is silicon oxide.
[0049] In some embodiments, the step of forming a sacrificial material on at least one switching device includes determining the thickness of the sacrificial material based on design requirements for subsequently forming a storage layer and at least one first conductive layer and at least one second conductive layer.
[0050] Precast trenches are used to define the location and size of the storage layer to be formed subsequently.
[0051] Specifically, the steps of forming a prefabricated trench within the sacrificial material include: forming a first pattern layer on the sacrificial material, with the first pattern layer exposing a portion of the sacrificial material; using the first pattern layer as a mask, etching the sacrificial material to form the prefabricated trench.
[0052] In some embodiments of this disclosure, a third barrier layer is further formed on the peripheral circuit and at least one switching device; the step of forming a prefabricated trench in the sacrificial material includes: forming a prefabricated trench in the sacrificial material with the bottom exposed to expose the third barrier layer.
[0053] like Figure 5 and Figure 6In some embodiments shown, the formation method further includes: after forming the third barrier layer 101, forming a sacrificial material 102 on the third barrier layer 101; etching a portion of the sacrificial material 102 on the peripheral circuit Peri, near at least one switching device 110, to expose the third barrier layer 101; forming a pre-made trench 121 in the sacrificial material 102, the pre-made trench 121 penetrating the sacrificial material 102 along a first direction x to expose the third barrier layer 101.
[0054] refer to Figure 7 and Figure 8 In some embodiments of the present invention, the forming method further includes: forming a first filling layer in a prefabricated trench, wherein the first filling layer penetrates the sacrificial material along a first direction.
[0055] in, Figure 7 This is a top view of the intermediate structure in some embodiments of the method for forming the present invention. Figure 8 yes Figure 7 A schematic diagram of the cross-sectional structure along line A3A3.
[0056] The first filler layer is used to occupy space for the subsequent formation of the memory layer. By using the first filler layer to occupy space for the formation of the memory layer, the memory layer can be formed after the patterning of at least one second conductive layer, which can effectively avoid damage to the memory layer and ensure the performance and quality of the memory layer.
[0057] In some embodiments of the present invention, the material of the first filling layer is different from the material of the third barrier layer, and the material of the first filling layer is different from the sacrificial material. Setting the first filling layer, the third barrier layer, and the sacrificial material to different materials can effectively prevent damage to the first filling layer during subsequent processes and effectively ensure the space required for the subsequent formation of the memory layer. Specifically, the material of the first filling layer includes, but is not limited to, silicon oxynitride.
[0058] like Figure 7 and Figure 8 In some embodiments shown, in the prefabricated trench 121 (e.g. Figure 5 and Figure 6 The step of forming a first filling layer 122 in the prefabricated trench 121 includes: filling a barrier material into the prefabricated trench 121, the barrier material extending onto the sacrificial material 102; and removing the barrier material from the sacrificial material 102 to form a first filling layer 122 located in the prefabricated trench 121.
[0059] refer to Figure 9 and Figure 10 In some embodiments of the present invention, the forming method further includes: after forming the first filling layer, removing the sacrificial material on one side of the first filling layer along the second direction.
[0060] in, Figure 9This is a top view of the intermediate structure in some embodiments of the method for forming the present invention. Figure 10 yes Figure 9 A schematic diagram of the cross-sectional structure along line A4A4.
[0061] The sacrificial material on one side of the first filler layer along the second direction is removed to provide space for the formation of the subsequent second conductive layer.
[0062] In some embodiments of the invention, the peripheral circuit is disposed on one side of at least one conductive layer along a first direction; the step of removing the sacrificial material on one side of the first filling layer along a second direction includes: removing the sacrificial material located on the side of the first filling layer along the second direction and on the side of the peripheral circuit along the first direction.
[0063] In some embodiments of the present invention, a third barrier layer is further formed on the peripheral circuit and at least one switching device; the step of removing the sacrificial material on one side of the first filling layer along the second direction includes: removing the sacrificial material on one side of the first filling layer along the second direction to expose the third barrier layer on the peripheral circuit. Specifically, the sacrificial material located on the side of the first filling layer near the peripheral circuit along the second direction is etched.
[0064] like Figure 9 and Figure 10 In some embodiments shown, a third barrier layer 101 is formed on the peripheral circuit Peri and at least one switching device 110; the step of removing the sacrificial material 102 on the side of the first filling layer 122 along the second direction y includes: removing the sacrificial material 102 located on the side of the first filling layer 122 along the second direction y on the peripheral circuit Peri, exposing the third barrier layer 101 above the peripheral circuit Peri.
[0065] refer to Figure 11 and Figure 14 In some embodiments of the present invention, the forming method further includes: forming at least one second filling layer on at least one switching device, on one side of the storage layer along the second direction.
[0066] in, Figure 11 This is a top view of the intermediate structure in some embodiments of the method for forming the present invention. Figure 12 yes Figure 11 A schematic diagram of the cross-sectional structure along line A5A5 in the middle; Figure 13 This is a top view of the intermediate structure in some embodiments of the method for forming the present invention. Figure 14 yes Figure 13 A schematic diagram of the cross-sectional structure along line A6A6.
[0067] The second filler layer is suitable for occupying space and providing preparation for the formation of the second conductive layer.
[0068] In some embodiments of the present invention, at least one switching device has a sacrificial material formed thereon; at least one second conductive layer is located on one side of the peripheral circuit along a first direction; before forming at least one second filling layer, the sacrificial material on one side of the first filling layer along a second direction is removed; the step of forming at least one second filling layer includes: forming at least one second filling layer in the area exposed by removing the sacrificial material.
[0069] In some embodiments, a third barrier layer is also formed on the peripheral circuit and at least one switching device; after the sacrificial material on one side of the first fill layer along the second direction is removed, the third barrier layer on the peripheral circuit is exposed; the step of forming at least one second fill layer includes: forming at least one second fill layer on the exposed third barrier layer.
[0070] Specifically, after removing the sacrificial material on one side of the first filler layer along the second direction, a third barrier layer on the peripheral circuit is exposed; the step of forming at least one second filler layer on the exposed third barrier layer includes: forming at least one second filler layer on the exposed third barrier layer on the peripheral circuit.
[0071] It should be noted that the side of the storage layer along the second direction refers to the side of the storage layer closer to the peripheral circuitry along the second direction.
[0072] In some embodiments of the present invention, at least one second filling layer is stacked along a first direction so that at least one second conductive layer is stacked along the first direction. The formation of the second filling layer stacked along the first direction, and the resulting second conductive layer stacked along the first direction, thereby realizing a three-dimensional structure of the memory cell, significantly improving storage density.
[0073] In some embodiments of the present invention, the intermediate structure further includes: at least one filling stack, the filling stack including: a second filling layer and a second barrier layer, the second barrier layer being located between the second filling layer and the switching device, thereby making the memory array further include: at least one conductive stack, the conductive stack including: a second conductive layer and a second barrier layer, the second barrier layer being located between the second conductive layer and the switching device.
[0074] The second barrier layer is used to separate adjacent second filler layers, thereby achieving electrical insulation between the subsequently formed second conductive layers.
[0075] Specifically, the second barrier layer is located between adjacent second fill layers and between adjacent second conductive layers subsequently formed; the second barrier layer is also located between the second fill layer closest to at least one switching device and the switching device, so as to achieve the connection between the second conductive layer closest to at least one switching device and the switching device subsequently formed.
[0076] In some embodiments of the example, a third barrier layer is also formed on the peripheral circuit and at least one switching device, and at least one second fill layer is formed on the exposed third barrier layer; the second fill layer is also located between the second fill layer and the third barrier layer closest to the at least one switching device.
[0077] In some embodiments of the present invention, the material of the second barrier layer is different from the material of the first filler layer, and the material of the second barrier layer is different from the material of the second filler layer. Using different materials for the second barrier layer, the first filler layer, and the second filler layer effectively prevents damage to the second barrier layer during subsequent processes and effectively ensures the electrical insulation performance between adjacent second conductive layers. Specifically, the material of the second barrier layer is, but is not limited to, silicon nitride.
[0078] In some embodiments of the present invention, along a first direction, the length of the fill stack away from the switching device is less than the length of the fill stack near the switching device, wherein the length is a dimension along a second direction, so that along the first direction, the length of the conductive stack away from the switching device is less than the length of the conductive stack near the switching device, wherein the length is a dimension along the second direction. Specifically, along the first direction, the length of at least one fill stack gradually decreases, so that all upper fill stacks expose lower fill stacks, and all second conductive layers on the side away from at least one switching device expose second conductive layers near at least one switching device. In a plane parallel to the surface of the substrate, each second conductive layer has an exposed area, thereby reducing the difficulty of leading out the second conductive layers.
[0079] In some embodiments of the present invention, all filler layers are flush with the side closest to the first filler layer, thereby making all conductive layers flush with the side closest to the storage layer. Specifically, all filler layers are flush with the side closest to the first filler layer, and a portion of the surface of any filler layer away from the first filler layer is exposed, thereby exposing the side of any second conductive layer away from the storage layer, so that the side of at least one second conductive layer away from the storage layer is stepped.
[0080] In some embodiments, the second filler layer is in contact with the surface of the first filler layer so that the second conductive layer is in contact with the surface of the storage layer. The second filler layer is in contact with the surface of the first filler layer so that the subsequently formed second conductive layer is in direct contact with the storage layer, thereby achieving electrical contact between them.
[0081] In some embodiments of the present invention, the step of forming at least one second filling layer includes: performing at least one stack forming operation on at least one switching device to form at least one prefabricated stack, wherein the stack forming operation includes: forming a second barrier material layer; forming a second filling material layer on the second barrier material layer; etching at least one prefabricated stack to form at least one filling stack, the filling stack including: a second barrier layer; a second filling layer, the second filling layer being located on the second barrier layer.
[0082] By performing at least one stacking operation, each stacking operation forms one prefabricated stack.
[0083] For example, the stacking operations include: forming a second barrier material layer by means of chemical vapor deposition, physical vapor deposition, and atomic layer deposition; and forming a second filler material layer on the second barrier material layer by means of chemical vapor deposition, physical vapor deposition, and atomic layer deposition.
[0084] At least one prefabricated stack is etched to expose all the upper fill stacks to the lower fill stacks, thereby providing a basis for the subsequent formation of a second conductive layer of suitable shape.
[0085] Specifically, the step of etching at least one prefabricated stack to form at least one fill stack includes: forming a patterned second patterned layer on at least one prefabricated stack, the second patterned layer exposing a portion of at least one fill stack away from the first fill layer; using the second patterned layer as a mask, etching the exposed portion of the fill stack to expose a second fill layer of the corresponding fill stack.
[0086] like Figure 11 and Figure 14 In some embodiments shown, at least one second filler layer 131 is formed on at least one switching device 110 (e.g., Figure 13 and Figure 14 The steps (as shown) include: Figure 11 and Figure 12 As shown, five prefabricated stacks 133a are formed on the third barrier layer 101 exposed on the first filler layer 122 along the second direction y. Each prefabricated stack 133a includes a second barrier material layer 132a and a second filler material layer 131a located on the second barrier material layer 132a. Figure 13 and Figure 14 As shown, four prefabricated stacks 133a are etched to form five filling stacks 133. The filling stacks 133 include a second barrier layer 132 and a second filling layer 131 located on the second barrier layer 132.
[0087] Moreover, as Figure 13 and Figure 14As shown, any two adjacent first filler layers among the five filler layers 133 are designated as first filler layer 133i and second filler layer 133j. First filler layer 133i and second filler layer 133j are arranged adjacent to each other along the first direction x, with first filler layer 133i located between second filler layer 133j and the third barrier layer 101. Both first filler layer 133i and second filler layer 133j are in contact with the side of first filler layer 122, and the length of first filler layer 133i is greater than the length of second filler layer 133j. A portion of the surface of first filler layer 133i on the side away from first filler layer 122 is not covered by second filler layer 133j and is exposed by second filler layer 133j. The five filler layers 133 on the side away from first filler layer 122 along the second direction y form a stepped shape along the second direction y.
[0088] refer to Figure 15 and Figure 16 In some embodiments of the present invention, the forming method further includes forming a cover layer on at least one switching device.
[0089] in, Figure 15 This is a top view of the intermediate structure in some embodiments of the method for forming the present invention. Figure 16 yes Figure 15 A schematic diagram of the cross-sectional structure along line A7A7.
[0090] In some embodiments, at least one second filler layer is further formed on at least one switching device; the step of forming a cover layer on at least one switching device includes: forming a cover layer on at least one second filler layer.
[0091] The capping layer covers at least one second filling layer to cover at least one subsequently formed second conductive layer, serving as an interlayer medium for achieving electrical isolation.
[0092] Specifically, the material of the capping layer is, but is not limited to, silicon oxide. For example, the step of forming a capping layer on at least one second filler layer includes forming the capping layer on at least one second filler layer by means of chemical vapor deposition, physical vapor deposition, and atomic layer deposition.
[0093] In some embodiments of the present invention, during the removal of the sacrificial material, only the sacrificial material on one side of the first filler layer along the second direction is removed, while the sacrificial material on the other side of the first filler layer along the second direction remains; in the step of forming a cover layer on at least one second filler layer, the cover layer also extends onto the remaining sacrificial material. Specifically, the cover layer is located on at least one second filler layer, the first filler layer, and the remaining sacrificial material.
[0094] like Figure 15 and Figure 16In some embodiments shown, the step of forming a cover layer 103 on at least one switching device 110 includes forming a cover layer 103 on at least one filler stack 133. The cover layer 103 covers all filler stacks 133 and extends to the first filler layer 122 and the remaining sacrificial material 102.
[0095] refer to Figure 17 and Figure 18 In some embodiments of the present invention, the forming method further includes: removing the first filling layer to expose the prefabricated trench before forming the storage layer.
[0096] in, Figure 17 This is a top view of the intermediate structure in some embodiments of the method for forming the present invention. Figure 18 yes Figure 17 A schematic diagram of the cross-sectional structure along line A8A8.
[0097] Precast trenches are used to form storage layers.
[0098] In some embodiments of the present invention, at least one switching device is further provided with a third barrier layer, and a first filling layer is located on the third barrier layer; the step of forming a prefabricated trench includes: forming a prefabricated trench with the bottom exposed to the third barrier layer.
[0099] In some embodiments of the present invention, before forming the storage layer, a cover layer is formed on at least one filler layer, and the cover layer extends to the first filler layer; before removing the first filler layer to expose the prefabricated trench, an extended trench is formed in the cover layer on the first filler layer, and the bottom of the extended trench exposes the first filler layer; the step of removing the first filler layer to expose the prefabricated trench includes: removing the first filler layer to expose the prefabricated trench and forming a storage trench, the storage trench including the extended trench and the prefabricated trench.
[0100] An extended groove is formed within the cover layer on the first filler layer to expose the first filler layer beneath the cover layer.
[0101] Specifically, the step of forming an extended trench within the capping layer on the first filler layer includes: forming a third patterned layer on the capping layer, the third patterned layer exposing the capping layer at a position corresponding to the first filler layer; using the third patterned layer as a mask, etching the capping layer until the first filler layer is exposed to form the extended trench.
[0102] After forming the extended trench and exposing the first filler layer, the exposed first filler layer is removed to form the storage trench, providing a basis for the formation of the storage layer.
[0103] Specifically, the step of removing the first filler layer to expose the prefabricated trench includes: removing the first filler layer by at least one etching method, either wet etching or dry etching, to form the storage trench.
[0104] In some embodiments, the material of the first filler layer is different from the material of the third barrier layer, the material of the first filler layer is different from the sacrificial material, the material of the first filler layer is different from the material of the second barrier layer, and the step of removing the first filler layer to expose the prefabricated trench includes: removing the first filler layer by wet etching.
[0105] like Figure 17 and Figure 18 In some embodiments shown, the first filler layer 122 is removed (e.g., Figure 15 and Figure 16 As shown, the step of exposing the prefabricated trench 141 includes: forming an extended trench 123 within a cover layer 103 on the first filling layer 122, with the bottom of the extended trench 123 exposing the first filling layer 122; removing the first filling layer 122 to expose the prefabricated trench 121, forming a storage trench 122, which includes the extended trench 123 and the prefabricated trench 121. The top of the prefabricated trench 121 and the bottom of the extended trench 123 are connected. The prefabricated trench 121 is located on the side of the extended trench 123 near at least one switching device 110.
[0106] refer to Figure 19 and Figure 20 The method of forming also includes forming a storage layer on at least one switching device.
[0107] in, Figure 19 This is a top view of the intermediate structure in some embodiments of the method for forming the present invention. Figure 20 yes Figure 19 A schematic diagram of the cross-sectional structure along line A9A9.
[0108] The storage layer is used to store data.
[0109] In some embodiments of the present invention, the step of forming a storage layer on at least one switching device includes: determining the storage layer material based on the type of storage array. In some embodiments, the storage array is a resistive switching storage array, and the storage layer material is a resistive switching material; in some embodiments, the storage array is a phase change storage array, and the storage layer material is a phase change material; in some embodiments, the storage array is a magnetic storage array, and the storage layer material is a ferromagnetic material; in some embodiments, the storage array is a ferroelectric storage array, and the storage layer material is a ferroelectric material.
[0110] In some embodiments of the present invention, before forming the storage layer, a first filler layer on at least one switching device is removed to expose a pre-made trench; the step of forming the storage layer includes: filling the pre-made trench with storage material to form a storage layer located within the pre-made trench.
[0111] In some embodiments, after removing the first filler layer, a storage trench including an extended trench and a prefabricated trench is formed; the step of forming the storage layer includes filling the storage trench with storage material to form a storage layer located within the storage trench.
[0112] like Figure 19 and Figure 20 In some embodiments shown, the step of forming a storage layer 120 on at least one switching device 110 includes: filling a storage trench 122 (e.g., ...) Figure 17 and Figure 18 The storage material is filled into the storage trench 122 (as shown), and the storage material extends onto the cover layer 103; the storage material on the cover layer 103 is removed to form a storage layer 120 located within the storage trench 122.
[0113] refer to Figure 21 and Figure 22 In some embodiments of the present invention, the forming method further includes: forming at least one first electrode opening on at least one switching device and on the other side of the storage layer along the second direction, wherein the at least one first electrode opening corresponds one-to-one with at least one switching device, and the bottom of the first electrode opening exposes one end of the corresponding switching device.
[0114] in, Figure 21 This is a top view of the intermediate structure in some embodiments of the method for forming the present invention. Figure 22 yes Figure 21 A schematic diagram of the cross-sectional structure along line A10A10.
[0115] It should be noted that, along the second direction, the side of the storage layer closer to the peripheral circuit is the side of the storage layer along the second direction; the other side of the storage layer along the second direction refers to the side of the storage layer away from the peripheral circuit along the second direction, that is, the side of the storage layer closer to at least one switching device along the second direction.
[0116] The opening of the first electrode is used to provide space and a process basis for the subsequent first conductive layer.
[0117] In some embodiments of the present invention, at least one switching device is further provided with a sacrificial material, and a cover layer is further provided on the remaining sacrificial material on at least one switching device; the step of forming at least one first electrode opening on the other side of the storage layer along the second direction includes: forming at least one first electrode opening in the cover layer and the sacrificial material on the other side of the storage layer along the second direction.
[0118] In some embodiments of the present invention, at least one switching device is further provided with a third barrier layer; the step of forming at least one first electrode opening in the cover layer and sacrificial material on the other side of the storage layer along the second direction includes: forming at least one first electrode opening in the cover layer, sacrificial material and third barrier layer on the other side of the storage layer along the second direction.
[0119] The first electrode opening extends along a first direction through the capping layer, the remaining sacrificial material, and the third barrier layer. The bottom of the first electrode opening exposes the corresponding switching device, allowing the first conductive layer formed in the first electrode opening to contact the switching device. For example, the bottom of the first electrode opening exposes the end face of one end of the channel post of the corresponding switching device along the first direction.
[0120] Specifically, the step of forming at least one first electrode opening on the other side of the storage layer along the second direction includes: forming a patterned fourth patterned layer on the cover layer; using the patterned fourth patterned layer as a mask, sequentially etching the cover layer, the remaining sacrificial layer and the third barrier layer to form at least one first electrode opening.
[0121] In some embodiments of the present invention, the step of forming at least one first electrode opening on at least one switching device and on the other side of the storage layer along the second direction includes: forming at least one first electrode opening parallel to a third direction on at least one switching device, wherein the third direction intersects with the first direction and intersects with the second direction, thereby causing the at least one first conductive layer subsequently formed to be arranged parallel to the third direction.
[0122] For example, the step of forming at least one first electrode opening on at least one switching device, on the other side of the storage layer along the second direction, includes: forming at least one first electrode opening on at least one switching device, on the other side of the storage layer along the second direction, by means of dry etching.
[0123] like Figure 21 and Figure 22 In some embodiments shown, the step of forming at least one first electrode opening on the storage layer on the other side of the second direction of at least one switching device includes: sequentially etching the cover layer 103, the remaining sacrificial layer (not shown) and the third barrier layer 101 to form at least one first electrode opening 142.
[0124] Specifically, the first electrode opening 142 is surrounded by a first barrier layer 143, a storage layer 120 and a corresponding switching device 110, wherein the first barrier layer 143 includes a cover layer, a sacrificial layer and a third barrier layer remaining after the formation of the first electrode opening 142; the bottom of the first electrode opening 142 exposes the end face of one end of the channel post 111 of the corresponding switching device 110 along the first direction x.
[0125] refer to Figure 23 and Figure 24 In some embodiments of the present invention, the forming method further includes: removing at least one second filling layer to form at least one second electrode opening.
[0126] in, Figure 23This is a top view of the intermediate structure in some embodiments of the method for forming the present invention. Figure 24 yes Figure 23 A schematic diagram of the cross-sectional structure along line A11A11.
[0127] The opening in the second electrode provides space for the formation of the second conductive layer.
[0128] Specifically, the step of removing the first filling layer to expose the pre-fabricated trench includes: removing at least one first filling layer by at least one etching method, either wet etching or dry etching, to form at least one second electrode opening.
[0129] In some embodiments, the material of the second filling layer is different from the material of the third barrier layer, and the material of the second filling layer is different from the sacrificial material; the material of the second filling layer is different from the material of the second barrier layer; the step of removing at least one second filling layer to form at least one second electrode opening includes: removing at least one second filling layer by wet etching.
[0130] In some embodiments of the present invention, the second filling layer extends along a second direction; in the step of forming at least one second electrode opening in addition to at least one second filling layer, the second electrode opening extends along a second direction.
[0131] In some embodiments of the present invention, at least one second filling layer is stacked along a first direction; the step of removing at least one second filling layer to form at least one second electrode opening includes: removing at least one second filling layer to form at least one second electrode opening stacked along the first direction.
[0132] In some embodiments of the present invention, along the first direction, the length of the filler stack away from the switching device is less than the length of the filler stack near the switching device; in the step of removing at least one second filler layer to form at least one second electrode opening, along the first direction, the length of the second electrode opening away from the switching device is less than the length of the second electrode opening near the switching device.
[0133] like Figure 23 and Figure 24 In some embodiments shown, at least one second filler layer 131 is removed (e.g. Figure 21 and Figure 22 As shown), at least one second electrode opening 134 is formed; the second electrode opening 134 is surrounded by a second barrier layer 132 and a cover layer 103.
[0134] refer to Figure 25 and Figure 26The forming method further includes: forming at least one first conductive layer and at least one second conductive layer on at least one switching device, wherein at least one first conductive layer is electrically connected to one end of at least one switching device in a one-to-one correspondence, wherein at least one first conductive layer and at least one second conductive layer are disposed along a second direction, and a storage layer is located between at least one first conductive layer and at least one second conductive layer, wherein the second direction intersects with the first direction.
[0135] in, Figure 25 This is a top view of the intermediate structure in some embodiments of the method for forming the present invention. Figure 26 yes Figure 25 A schematic diagram of the cross-sectional structure along line A12A12.
[0136] The first and second conductive layers serve as the two electrode plates of the capacitor, located on both sides of the storage layer along the second direction, and apply voltage to the storage layer for data control.
[0137] In some embodiments of the present invention, the first electrode opening penetrates the cover layer, the remaining sacrificial material and the third barrier layer along the first direction, and the first electrode opening of the first conductive layer penetrates the cover layer, the remaining sacrificial material and the third barrier layer along the first direction.
[0138] In some embodiments of the present invention, the bottom of the opening of the first electrode exposes the corresponding switching device; the end of the first conductive layer near the switching device is in contact with the switching device to achieve electrical connection.
[0139] In some embodiments of the present invention, at least one first electrode opening is arranged parallel to a third direction; in the step of forming at least one first conductive layer and at least one second conductive layer on at least one switching device, at least one first conductive layer is arranged parallel to a third direction.
[0140] In some embodiments of the present invention, the second electrode opening extends along a second direction; the second conductive layer extends along a second direction.
[0141] In some embodiments of the present invention, at least one second electrode opening is stacked along a first direction; at least one second conductive layer is stacked along the first direction.
[0142] In some embodiments, along the first direction, the length of the second electrode opening away from the switching device is less than the length of the second electrode opening near the switching device; and along the first direction, the length of the second conductive layer away from the switching device is less than the length of the second conductive layer near the switching device.
[0143] In some embodiments of the example, in the step of forming at least one first conductive layer and at least one second conductive layer on at least one switching device, at least one conductive stack is formed, the conductive stack comprising: a second conductive layer and a second barrier layer, the second barrier layer being located between the second conductive layer and the switching device.
[0144] In some embodiments of the present invention, the step of forming at least one first conductive layer and at least one second conductive layer on at least one switching device includes: filling at least one first electrode opening and at least one second electrode opening with conductive material to form a first conductive layer located in the first electrode opening and a second conductive layer located in the second electrode opening.
[0145] Specifically, the conductive material can be a metallic material. The steps of forming a first conductive layer in a first electrode opening and a second conductive layer in a second electrode opening include: filling at least one first electrode opening and at least one second electrode opening with conductive material, the conductive material extending onto a capping layer and a storage layer; and removing the conductive material from the capping layer and the storage layer to form at least one first conductive layer and at least one second conductive layer.
[0146] like Figure 25 and Figure 26 In some embodiments shown, the step of forming at least one first conductive layer 140 and at least one second conductive layer 130 on at least one switching device 110 includes: forming at least one first electrode opening 142 (e.g., ... Figure 23 and Figure 24 As shown, at least one first conductive layer 140 and at least one second conductive layer 130 are filled with conductive material within at least one second electrode opening 134 to form at least one first conductive layer 140 and at least one second conductive layer 130. The at least one second conductive layer 130 and at least one second barrier layer 132 are adapted to form at least one conductive stack 135.
[0147] It should be noted that the reference Figures 27 to 29 In some embodiments of the present invention, the forming method further includes: forming at least one contact plug, wherein the at least one contact plug is connected to at least one second conductive layer in a one-to-one correspondence, and the contact plug penetrates the cover layer of the corresponding second conductive layer on one side along the first direction.
[0148] in, Figure 27 This is a three-dimensional structural diagram of the intermediate structure in some embodiments of the method for forming the present invention. Figure 28 This is a top view of the intermediate structure in some embodiments of the method for forming the present invention. Figure 29 yes Figure 28 A schematic diagram of the cross-sectional structure along line A13A13.
[0149] Contact plugs are suitable for achieving electrical connection between the corresponding second conductive layer and the external circuit.
[0150] In some embodiments of the present invention, a second conductive layer is partially not covered by the upper conductive stack at one end away from the storage layer 120 along the second direction; the position of the corresponding contact plug corresponds to the position of the portion of the second conductive layer not covered by the upper conductive stack, that is, the projection of the contact plug on the surface of the corresponding second conductive layer is located within the range of the portion of the second conductive layer not covered by the upper conductive stack; the contact plug penetrates the cover layer and contacts the portion of the second conductive layer not covered by the upper conductive stack.
[0151] Specifically, the step of forming at least one contact plug includes: etching a cover layer to form a contact hole within the cover layer, exposing a corresponding second conductive layer at the bottom of the contact hole; and depositing a conductive material in the contact hole to form a contact plug.
[0152] like Figures 27 to 29 In some embodiments shown, the step of forming at least one contact plug 150 includes: forming a contact hole in the cover layer 103, the bottom of the contact hole exposing a portion of the second conductive layer 130 not covered by the upper conductive stack 135; and forming the contact plug 150 in the contact hole.
[0153] Accordingly, the present invention also provides a storage array.
[0154] refer to Figures 27 to 29 The diagram shows a schematic representation of the structure of some embodiments of the storage array of the present invention.
[0155] in, Figure 27 This is a three-dimensional structural diagram of some embodiments of the storage array of the present invention. Figure 28 This is a top view schematic diagram of some embodiments of the storage array of the present invention. Figure 29 yes Figure 28 A schematic diagram of the cross-sectional structure along line A13A13.
[0156] The storage array includes:
[0157] At least one switching device 110; at least one first conductive layer 140, the at least one first conductive layer 140 being located on one side of the at least one switching device 110 along a first direction x, the at least one first conductive layer 140 being electrically connected to one end of the at least one switching device 110 in a one-to-one correspondence; at least one second conductive layer 130, the at least one second conductive layer 130 being located on one side of the at least one first conductive layer 140 along a second direction y, the at least one second conductive layer 130 extending along the second direction y, wherein the second direction y intersects the first direction x; a storage layer 120, the storage layer 120 being located between the at least one second conductive layer 130 and the at least one first conductive layer 140.
[0158] In some embodiments of the present invention, the storage array is formed by the storage array formation method of the present invention. Specific technical solutions for the storage array can be found in the foregoing. Figures 2 to 29 The example shown.
[0159] It should be noted that, in the foregoing embodiments, along the first direction, the length of the conductive stack away from at least one switching device is less than the length of the conductive stack near the switching device, wherein the length is the dimension along the second direction. In other embodiments of the present invention, along the first direction, at least one of the length and width of the conductive stack away from the switching device is less than that of the conductive stack near the switching device.
[0160] refer to Figure 30 The diagram shows a three-dimensional structural schematic of some other embodiments of the storage array of the present invention.
[0161] Unlike the aforementioned embodiments, in some embodiments of the present invention, the width of the conductive stack away from at least one switching device along the first direction is smaller than the width of the conductive stack close to the switching device, wherein the width is the dimension along a third direction, the third direction intersects the first direction, and the third direction intersects the second direction.
[0162] Specifically, along the first direction away from at least one switching device, the width of the conductive stack decreases layer by layer, so that the multiple conductive stacks are in a stepped shape along the third direction on one side.
[0163] like Figure 30 In some embodiments shown, along the first direction x away from at least one switching device 210, the width and length of the plurality of conductive stacks 235 decrease layer by layer, such that two portions of the second conductive layer 230 of any conductive stack 235 are not covered by the upper conductive stack 235; two contact plugs 250 are respectively located on the two portions of the second conductive layer 230 not covered by the upper conductive stack 235, and the density of the contact plugs 250 is greater to improve the storage density.
[0164] In summary, by placing the storage layer between at least one first conductive layer and at least one second conductive layer along the second direction, extending the storage layer along the first direction and extending the first conductive layer along the second direction, a three-dimensional structure of the storage cell can be achieved, which can greatly improve the storage density. Moreover, at least one switching device is located on one side of at least one first conductive layer and at least one second conductive layer along the first direction, which can effectively save the area occupied by the switching device in the storage area while controlling the leakage path, thus effectively improving the storage density.
[0165] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.
Claims
1. A storage array, characterized in that, include: At least one switching device; At least one first conductive layer is located on one side of the at least one switching device along a first direction, and the at least one first conductive layer is electrically connected to one end of the at least one switching device in a one-to-one correspondence. At least one second conductive layer is located on one side of the at least one first conductive layer along a second direction, and the at least one second conductive layer extends along the second direction, wherein the second direction intersects the first direction; A storage layer located between the at least one second conductive layer and the at least one first conductive layer.
2. The storage array as described in claim 1, characterized in that, The at least one first conductive layer is arranged parallel to a third direction, which intersects the first direction and the second direction.
3. The storage array as described in claim 2, characterized in that, Also includes: A first barrier layer is located between adjacent first conductive layers.
4. The storage array as described in claim 1, characterized in that, The at least one second conductive layer is stacked along the first direction.
5. The storage array as described in claim 4, characterized in that, Also includes: At least one conductive stack, the conductive stack comprising: a second conductive layer and a second barrier layer, the second barrier layer being located between the second conductive layer and the switching device.
6. The storage array as described in claim 5, characterized in that, Along the first direction, the length of the conductive stack away from the at least one switching device is less than the length of the conductive stack near the at least one switching device, wherein the length is a dimension along the second direction.
7. The storage array as described in claim 5, characterized in that, Along the first direction, the width of the conductive stack away from the at least one switching device is smaller than the width of the conductive stack near the at least one switching device, wherein the width is a dimension along a third direction that intersects the first direction and the second direction.
8. The storage array as described in claim 5, 6, or 7, characterized in that, All of the conductive layers are flush with the side closest to the storage layer.
9. The storage array as described in claim 8, characterized in that, The second conductive layer is in contact with the surface of the storage layer.
10. The storage array as claimed in claim 1, characterized in that, The switching device is a vertical channel switching device, and the channel of the switching device extends along the first direction.
11. The storage array as claimed in claim 1 or 10, characterized in that, The switching device includes: A channel post, the channel post extending along the first direction; A fully enclosed gate structure, wherein the fully enclosed gate structure circumferentially surrounds the channel pillar along the first direction.
12. The storage array as claimed in claim 11, characterized in that, One end of the channel post along the first direction is in contact with the first conductive layer.
13. The storage array as claimed in claim 1, characterized in that, Also includes: A cover layer, the cover layer being located on the side of the at least one second conductive layer away from the at least one switching device along a first direction; At least one contact plug, the at least one contact plug being connected to the at least one second conductive layer in a one-to-one correspondence, the contact plug penetrating the cover layer of the corresponding second conductive layer on one side along the first direction.
14. The storage array as claimed in claim 1, characterized in that, Also includes: The peripheral circuit is located on the side of the second conductive layer closest to the switching device along the first direction, and the peripheral circuit is located on the side of the at least one switching device along the second direction. A third barrier layer is located between the storage layer and the second conductive layer closest to the switching device and the peripheral circuit.
15. The storage array as claimed in claim 1, characterized in that, The material of the storage layer is one of resistive switching materials, phase change materials, ferromagnetic materials, and ferroelectric materials.
16. A method for forming a memory array, characterized in that, include: A substrate is provided, wherein a direction perpendicular to the surface of the substrate is a first direction; At least one switching device is formed on the substrate; A storage layer is formed on the at least one switching device; At least one first conductive layer and at least one second conductive layer are formed on the at least one switching device, the at least one first conductive layer is electrically connected to one end of the at least one switching device, the at least one first conductive layer and the at least one second conductive layer are disposed along a second direction, and the storage layer is located between the at least one first conductive layer and the at least one second conductive layer, wherein the second direction intersects with the first direction.
17. The forming method as described in claim 16, characterized in that, Also includes: A sacrificial material is formed on the at least one switching device; A prefabricated trench is formed within the sacrificial material, the prefabricated trench penetrating the sacrificial material along the first direction; A first filling layer is formed within the prefabricated trench; Before forming the storage layer, the first filler layer is removed to expose the prefabricated trench; The step of forming the storage layer includes filling the prefabricated trench with storage material to form a storage layer located within the prefabricated trench.
18. The forming method as described in claim 17, characterized in that, Also includes: A cover layer is formed on the at least one switching device; An extended groove is formed within a cover layer on a first filler layer, the bottom of which is exposed above the first filler layer. The step of removing the first filler layer to expose the prefabricated trench includes: removing the first filler layer to expose the prefabricated trench, forming a storage trench, wherein the storage trench includes the extended trench and the prefabricated trench; The step of forming the storage layer includes: filling the storage trench with storage material to form a storage layer located within the storage trench.
19. The forming method as described in claim 16, characterized in that, Also includes: At least one second filling layer is formed on one side of the storage layer along the second direction on the at least one switching device; At least one first electrode opening is formed on the storage layer along the second direction on the at least one switching device, and the at least one first electrode opening corresponds to the at least one switching device, with the bottom of the first electrode opening exposing one end of the corresponding switching device. Remove the at least one second filler layer to form at least one second electrode opening; The step of forming at least one first conductive layer and at least one second conductive layer on the at least one switching device includes: filling the at least one first electrode opening and the at least one second electrode opening with conductive material to form a first conductive layer located in the first electrode opening and a second conductive layer located in the second electrode opening.
20. The forming method as described in claim 19, characterized in that, Also includes: Before forming at least one second filler layer, the sacrificial material of the first filler layer along one side of the second direction is removed; The step of forming at least one second filler layer includes: forming at least one second filler layer in the area exposed by removing the sacrificial layer; The step of forming a cover layer on the at least one switching device includes: forming a cover layer on the at least one second filler layer, the cover layer further extending onto the remaining sacrificial material; The step of forming at least one first electrode opening on the other side of the storage layer along the second direction includes: forming at least one first electrode opening within the cover layer and sacrificial material on the other side of the storage layer along the second direction.
21. The forming method as described in claim 20, characterized in that, The steps of forming at least one second filler layer include: At least one stacking operation is performed on the at least one switching device to form at least one prefabricated stack, wherein the stacking operation includes: forming a second barrier material layer; forming a second filler material layer on the second barrier material layer; The at least one prefabricated stack is etched to form at least one filled stack, the filled stack comprising: a second barrier layer; and a second filled layer, the second filled layer being located on the second barrier layer.
22. The forming method as described in claim 16, characterized in that, Also includes: After forming at least one switching device on the substrate, a third barrier layer is formed on the at least one switching device; The step of forming a prefabricated trench within the sacrificial material includes: forming a prefabricated trench within the sacrificial material with the bottom exposed to the third barrier layer; Before forming at least one second filler layer, the step of removing the sacrificial material of the first filler layer along the second direction includes: removing the sacrificial material of the first filler layer along the second direction to expose the third barrier layer; The step of forming at least one first electrode opening within the cover layer and sacrificial material on the other side of the storage layer along the second direction includes: forming at least one first electrode opening within the cover layer, sacrificial material, and third barrier layer on the other side of the storage layer along the second direction.
23. The forming method as described in claim 16, characterized in that, Also includes: On the substrate, a peripheral circuit is formed on one side of the at least one switching device along the second direction; A third barrier layer is formed on the peripheral circuit and the at least one switching device; The step of removing the sacrificial material on one side of the first filler layer along the second direction to expose the third barrier layer includes: removing the sacrificial material on one side of the first filler layer along the second direction to expose the third barrier layer on the peripheral circuit.
24. The forming method as described in claim 16, characterized in that, Also includes: At least one contact plug is formed, and the at least one contact plug is connected to the at least one second conductive layer in a one-to-one correspondence. The contact plug penetrates the cover layer of the corresponding second conductive layer on one side along the first direction.
25. The forming method as described in claim 16, characterized in that, Also includes: In the step of forming a storage layer on the at least one switching device, the material of the storage layer is one of resistive switching material, phase change material, ferromagnetic material and ferroelectric material.