Mechanical memristor and preparation method thereof

Abstract

The invention discloses a mechanical memristor and a preparation method thereof. The mechanical memristor comprises a gold film layer, a single crystal graphite layer and a substrate layer which are sequentially stacked from top to bottom, the two same single crystal graphite layers are symmetrically arranged at the upper end of the substrate layer, and a lower channel is formed in the middle area of the two single crystal graphite layers; and the gold film layers respectively stride the upper ends of the single crystal graphite layers on the two sides. According to the mechanical memristor disclosed by the invention, after a loop is electrified, the gold film layer can move along the extension direction of the lower channel under the action of a magnetic field and finally reaches a balance state and then is static under the action of friction force, and the contact area between the gold film layer and the single crystal graphite layer is changed after the gold film layer is displaced, so that the mechanical memristor has the advantages that the mechanical memristor is stable in performance; the resistance value of the mechanical memristor is correspondingly changed, so that the signal is recorded, and controllable resistance change and historical electric signal memory functions can be realized through the reversible process.

Description

Technical Field

[0001] This invention relates to the field of storage device technology, and in particular to a mechanical memristor and its fabrication method. Background Technology

[0002] Van der Waals layered materials have rapidly become a cutting-edge field internationally due to their excellent mechanical, thermal, and electrical properties, and have shown great application potential in areas such as nanocomposites, flexible electronic devices, and microelectromechanical systems (MEMS). In particular, self-superlubricating interfaces composed of van der Waals materials possess extremely low friction and zero wear characteristics at the micro- and nano-scale, and are expected to achieve in-plane sliding at the micro- and nano-scale.

[0003] Current memristor structures are insufficient for achieving stable storage of high-density data over extremely long periods. Therefore, there is an urgent need for a mechanical memristor to address the problem of storing large-scale static cold data over extremely long periods and the problem of multi-value storage in analog neuromorphic computing. Summary of the Invention

[0004] In view of the above problems, the present invention is proposed to provide a mechanical memristor and a method for its fabrication that overcomes or at least partially solves the above problems.

[0005] Other features and advantages of the invention will become apparent from the following detailed description, or may be learned in part by practice of the invention.

[0006] According to a first aspect of the present invention, a mechanical memristor is provided, comprising: a gold film layer, a single-crystal graphite layer and a substrate layer stacked sequentially from top to bottom; Two identical single-crystal graphite layers are symmetrically disposed on the upper end of the substrate layer, and a lower channel is formed in the middle region of the two single-crystal graphite layers; The gold film layer spans the upper ends of the single-crystal graphite layers on both sides, and the length direction of the gold film layer is perpendicular to the extension direction of the lower channel. The lower end of the gold film layer has an upper channel corresponding to the position of the lower channel. The gold film layer, the single-crystal graphite layer, and the substrate layer are placed in a magnetic environment, and the two single-crystal graphite layers are respectively connected to the two poles of the power supply to form a circuit.

[0007] In some embodiments of the present invention, the gold film layer has the same contact area with the upper ends of the two single-crystal graphite layers.

[0008] In some embodiments of the present invention, the cross-sectional shape of the gold film layer is a rectangular or circular shape that is symmetrical from left to right.

[0009] In some embodiments of the present invention, the lower channel is formed on the inner sides of the two opposing monocrystalline graphite layers, and the cross-sectional shape of the inner sides of the two opposing monocrystalline graphite layers is a sloping surface or an equally spaced step shape.

[0010] In some embodiments of the present invention, the thickness of the gold film layer is 100-500 nm, the length of the gold film layer is 10-30 μm, and the width of the gold film layer is 2-10 μm.

[0011] In some embodiments of the present invention, the thickness of the single-crystal graphite layer is 500-2000 nm.

[0012] In some embodiments of the present invention, a permanent magnet is disposed at the bottom of the substrate layer, and the permanent magnet provides a magnetic field perpendicular to the gold film layer.

[0013] In some embodiments of the present invention, the substrate layer is made of silicon dioxide or aluminum oxide.

[0014] According to a second aspect of the present invention, a method for fabricating a mechanical memristor is provided, comprising the following steps: S1. Using a silicon dioxide substrate with a pre-grown single-crystal graphite layer as the basic template, a gold film layer is deposited on the surface of the single-crystal graphite layer in a vacuum thermal evaporation chamber at 1000℃ using thermal evaporation technology to form the first layered structure. S2. After the gold film layer is deposited, photoresist is uniformly spin-coated on the surface of the gold film layer to form a photoresist layer. The photoresist layer is patterned by photolithography and etching processes to obtain a second stacked structure with a lower channel. S3. A first sacrificial layer is deposited on the surface of the photoresist layer by magnetron sputtering, and a second sacrificial layer is deposited on the surface of the lower channel to obtain a third stacked structure. S4. The third stacked structure is cleaned using a photoresist stripping solution to remove the first sacrificial layer and photoresist layer on the surface of the gold film layer, resulting in the fourth stacked structure. S5. Using thermal evaporation technology, a second gold deposition is performed on the gold film layer and the second sacrificial layer on the surface of the fourth stacked structure in a vacuum thermal evaporation chamber at 1000°C to obtain the fifth stacked structure. S6. The surface of the fifth layer structure is processed by etching according to the target layout to obtain a plurality of first bridging structures that are mutually insulated and have independent functions. S7. Use a wet process to remove the second sacrificial layer on the first bridging structure to obtain a suspended second bridging structure; S8. Photoresist is uniformly spin-coated again on the upper surface of the second bridging structure to form a photoresist layer. The photoresist layer on the surface of the gold film layer is removed by photolithography. Then, the gold film layer is etched by wet etching to form a slider-type gold film layer. The gold film layer spans the upper ends of the single crystal graphite layers on both sides, and the length direction of the gold film layer is perpendicular to the extension direction of the lower channel. The middle area is a suspended upper channel and lower channel, thus obtaining the basic configuration of the mechanical memristor. S9. A permanent magnet is added to the bottom of the basic configuration, and an external power supply circuit is connected to the single-crystal graphite layers on both sides to obtain the mechanical memristor.

[0015] In some embodiments of the present invention, in step S1, the thickness of the single-crystal graphite layer is 0.5 μm, and the thickness of the gold film layer is 200 nm.

[0016] In some embodiments of the present invention, in step S3, the first sacrificial layer and the second sacrificial layer are made of aluminum, and the thickness of the first sacrificial layer and the second sacrificial layer is 600 nm.

[0017] In some embodiments of the present invention, in step S6, the process of etching the surface of the fifth layer structure according to the target layout to obtain a plurality of mutually insulated and independently functional first bridging structures includes: Determine the boundary lines of each of the first bridging structures according to the target layout; A photoresist layer is formed by uniformly spin-coating photoresist onto the surface of the fifth stacked structure. The boundary line is etched using an ion beam etching process to remove the gold film layer at the boundary line location. The boundary line is etched using a reactive ion etching process to remove the single-crystal graphite layer at the boundary line location, thereby obtaining multiple first bridging structures that are mutually insulated and have independent functions.

[0018] In some embodiments of the present invention, the reactive ion etching process is carried out in an oxygen or hydrogen environment of 200 mbar and the reaction temperature is 400-700°C.

[0019] In some embodiments of the present invention, in step S4, the photoresist stripping solution is N-methyl-2-pyrrolidone.

[0020] The technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: In the embodiment of the present invention, after the circuit is energized, the gold film layer of the mechanical memristor can move along the extension direction of the lower channel under the action of a magnetic field, and eventually reach a state of equilibrium and come to rest under the action of friction. Since the contact area between the gold film layer and the single crystal graphite layer changes after the displacement, the resistance value of the mechanical memristor is changed accordingly, thereby realizing the recording of signals. Through this reversible process, controllable resistance change and historical electrical signal memory function can be realized, which has good non-volatility, and can achieve an ultra-long static data storage life, and the dynamic read and write times are also greatly improved.

[0021] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a side view of a mechanical memristor provided in an embodiment of the present invention; Figure 2 This is a top view of a mechanical memristor provided in an embodiment of the present invention; Figure 3 A schematic flowchart illustrating a method for fabricating a mechanical memristor according to an embodiment of the present invention; Figure 4 A schematic diagram of the structure for obtaining the first layered structure by thermally evaporating a gold film layer on single-crystal graphite; Figure 5 This is a schematic diagram of the second-layer structure obtained by etching after spin-coating photoresist; Figure 6 A schematic diagram of the structure for obtaining the third layered structure by depositing the first and second sacrificial layers; Figure 7 A schematic diagram of the fourth-layer structure obtained after removing the photoresist; Figure 8 A schematic diagram of the structure for obtaining the fifth layer of the stacked structure by re-depositing a gold film layer; Figure 9 A schematic diagram of the first bridging structure obtained by etching after spin-coating photoresist; Figure 10A schematic diagram of the second bridging structure obtained after removing the sacrificial layer; Figure 11 This is a schematic diagram of the basic configuration of a mechanical memristor obtained by etching after spin coating with photoresist.

[0024] Explanation of reference numerals in the attached figures: 1. Gold film layer; 2. Single crystal graphite layer; 3. Substrate layer; 5. Upper channel; 6. Lower channel; 7. Photoresist layer; 8. First sacrificial layer; 9. Second sacrificial layer. Detailed Implementation

[0025] Exemplary embodiments of this application will now be described in more detail with reference to the accompanying drawings.

[0026] The accompanying drawings illustrate various structural schematics according to embodiments of this application. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0027] It should be noted that the terms "first," "second," etc., used in this application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "comprising" and "having," and any variations thereof, used in this application, are intended to cover non-exclusive inclusion. The term "multiple" used in this application refers to two or more. In the context of this application, similar or identical parts may be represented by the same or similar reference numerals.

[0028] To better understand the above technical solutions, the following will describe the above technical solutions in detail with reference to specific implementation methods. It should be understood that the embodiments of this application and the specific features in the embodiments are detailed descriptions of the technical solutions of the present invention, rather than limitations on the technical solutions of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0029] Figure 1 This is a schematic flowchart of a mechanical memristor provided in an embodiment of the present invention. Figure 2 This is a top view schematic diagram of a mechanical memristor provided in an embodiment of the present invention, as shown below. Figure 1-2As shown, the mechanical memristor includes: a gold film layer 1, a single-crystal graphite layer 2, and a substrate layer 3 stacked sequentially from top to bottom; the substrate layer 3 is made of silicon dioxide or aluminum oxide; two identical single-crystal graphite layers 2 are symmetrically disposed on the upper end of the substrate layer 3, and the middle region of the two single-crystal graphite layers 2 forms a lower channel 6; the gold film layer 1 spans the upper ends of the single-crystal graphite layers 2 on both sides, and the length direction of the gold film layer 1 is perpendicular to the extension direction of the lower channel 6; an upper channel 5 is formed at the lower end of the gold film layer 1 corresponding to the position of the lower channel 6; the gold film layer 1, the single-crystal graphite layer 2, and the substrate layer 3 are placed in a magnetic environment, and the two single-crystal graphite layers 2 are respectively connected to the two poles of the power supply to form a circuit.

[0030] In this embodiment of the invention, a permanent magnet can be disposed at the bottom of the substrate layer 3 to form a magnetic environment, which provides a magnetic field perpendicular to the gold film layer 1; the two single-crystal graphite layers 2 are respectively connected as two connecting electrodes to the positive and negative terminals of an external power supply to form a circuit.

[0031] Since there is a corresponding relationship between the contact area of ​​the gold film layer 1 and the two single-crystal graphite layers 2 and the contact resistance value of the mechanical memristor, in this embodiment of the invention, the contact area at the upper end of the gold film layer 1 and the two single-crystal graphite layers 2 is the same, thereby enabling the two ends of the gold film layer 1 and the two single-crystal graphite layers 2 to form the same contact resistance; the cross-sectional shape of the gold film layer 1 is a rectangular or circular shape that is symmetrical from left to right; in other embodiments, it can also be other symmetrical shapes, such as triangles or trapezoids.

[0032] In this embodiment of the invention, the thickness of the gold film layer 1 is 100-500 nm, the length of the gold film layer 1 is 10-30 μm, and the width of the gold film layer 1 is 2-10 μm.

[0033] In this embodiment of the invention, the thickness of the single-crystal graphite layer 2 is 500-2000 nm; the inner cross-sectional shape of the two opposing single-crystal graphite layers 2 is a sloping surface or an equally spaced step shape (or an arc shape), the two single-crystal graphite layers 2 are symmetrically arranged, and the lower channel 6 is formed on the inner side of the two opposing single-crystal graphite layers 2. When the gold film layer 1 is displaced along the lower channel 6, the resistance value of the mechanical memristor is controlled by the change in the contact area between the gold film layer 1 and the single-crystal graphite layer 2 after the gold film layer 1 is displaced.

[0034] In the embodiment of the present invention, after the circuit is energized, the gold film layer 1 of the mechanical memristor can move along the extension direction of the lower channel 6 under the action of a magnetic field, and eventually reach a state of equilibrium and come to rest under the action of friction. Since the contact area between the gold film layer 1 and the single crystal graphite layer 2 changes after the displacement, the resistance value of the mechanical memristor is changed accordingly, thereby realizing the recording of signals. Through this reversible process, controllable resistance change and historical electrical signal memory function can be realized, which has good non-volatility, and can also achieve an ultra-long static data storage life, and the dynamic read and write times are also greatly improved.

[0035] Based on the above embodiments, see [link to relevant documentation]. Figure 3 The diagram shown is a schematic flowchart of the fabrication method of the mechanical memristor. This invention also provides a method for fabricating a mechanical memristor, combined with... Figure 4-11 As shown, it includes the following steps: S1. Using a silicon dioxide substrate 3 with a pre-grown single-crystal graphite layer 2 as the basic template, a gold film layer 1 is deposited on the surface of the single-crystal graphite layer 2 in a vacuum thermal evaporation chamber at 1000°C using thermal evaporation technology to form the first layered structure. S2. After the gold film layer 1 is deposited, photoresist is uniformly spin-coated on the surface of the gold film layer 1 to form a photoresist layer 7. The photoresist layer 7 is patterned by photolithography and etching processes to obtain a second stacked structure with a lower channel 6. S3. A first sacrificial layer 8 is deposited on the surface of the photoresist layer 7 by magnetron sputtering, and a second sacrificial layer 9 is deposited on the surface of the lower channel 6 to obtain a third stacked structure. S4. The third stacked structure is cleaned using a photoresist stripping solution to remove the first sacrificial layer 8 and the photoresist layer 7 on the surface of the gold film layer 1, thereby obtaining the fourth stacked structure. S5. Using thermal evaporation technology, a second gold deposition is performed on the gold film layer 1 and the second sacrificial layer 9 on the surface of the fourth stacked structure in a vacuum thermal evaporation chamber at 1000°C to obtain the fifth stacked structure. S6. The surface of the fifth layer structure is processed by etching according to the target layout to obtain a plurality of first bridging structures that are mutually insulated and have independent functions. S7. Use a wet process to remove the second sacrificial layer 9 on the first bridging structure to obtain a suspended second bridging structure. S8. Photoresist is uniformly spin-coated again on the upper surface of the second bridging structure to form a photoresist layer 7, and the photoresist layer 7 on the surface of the gold film layer 1 is removed by photolithography. Then, the gold film layer 1 is etched by wet etching to form a slider-type gold film layer 1. The gold film layer 1 spans the upper ends of the single crystal graphite layers 2 on both sides, and the length direction of the gold film layer 1 is perpendicular to the extension direction of the lower channel 6. The middle area is a suspended upper channel 5 and lower channel 6, thus obtaining the basic configuration of the mechanical memristor. S9. A permanent magnet is added to the bottom of the basic configuration, and an external power supply circuit is connected to the single crystal graphite layers 2 on both sides to obtain the mechanical memristor.

[0036] In step S1 of this embodiment of the invention, the thickness of the single-crystal graphite layer 2 is 0.5 μm, and the thickness of the gold film layer 1 is 200 nm.

[0037] In step S2 of this embodiment of the invention, the photoresist is, for example, AZ1500 (20cp).

[0038] In step S3 of this embodiment of the invention, the first sacrificial layer 8 and the second sacrificial layer 9 are made of aluminum, and the thickness of the first sacrificial layer 8 and the second sacrificial layer 9 is 600 nm.

[0039] In step S4 of this embodiment of the invention, the photoresist stripping solution is N-methyl-2-pyrrolidone.

[0040] In step S6 of this embodiment of the invention, the step of processing the surface of the fifth layered structure according to the target layout using an etching process to obtain a plurality of mutually insulated and independently functional first bridging structures includes: Determine the boundary lines of each of the first bridging structures according to the target layout; Photoresist layer 7 is formed by uniformly spin-coating photoresist onto the surface of the fifth stacked structure; The boundary line is etched using an ion beam etching process to remove the gold film layer 1 at the boundary line location. The boundary line is etched using a reactive ion etching process to remove the single-crystal graphite layer 2 at the boundary line location, thereby obtaining multiple first bridging structures that are mutually insulated and have independent functions.

[0041] The reactive ion etching process is carried out in an oxygen or hydrogen environment of 200 mbar and at a reaction temperature of 400-700℃.

[0042] In step S7 of this embodiment of the invention, the wet process uses an aluminum etching solution (mainly dilute nitric acid) to remove the second sacrificial layer 9.

[0043] In step S8 of this embodiment of the invention, the wet etching process uses a wet gold removal solution (product model: Beichen BC046) to etch the gold film layer 1.

[0044] The method for preparing a mechanical memristor according to the embodiments of the present invention can prepare the mechanical memristor provided in the above embodiments. The mechanical memristor obtained by the method for preparing the mechanical memristor has the corresponding functional components and beneficial effects of the mechanical memristor described in the above embodiments. For details, please refer to the embodiments of the mechanical memristor described above. The embodiments of the present invention will not be repeated here.

[0045] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0046] Similarly, it should be understood that, for the purpose of simplification and aiding understanding of one or more aspects of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of the invention above. Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and it should be noted that the above embodiments are illustrative of the invention and not restrictive, and that alternative embodiments can be devised by those skilled in the art without departing from its scope.

Claims

1. A mechanical memristor, characterized in that, include: The layers are stacked from top to bottom: a gold film layer, a single-crystal graphite layer, and a substrate layer. Two identical single-crystal graphite layers are symmetrically disposed on the upper end of the substrate layer, and a lower channel is formed in the middle region of the two single-crystal graphite layers; The gold film layer spans the upper ends of the single-crystal graphite layers on both sides, and the length direction of the gold film layer is perpendicular to the extension direction of the lower channel. The lower end of the gold film layer has an upper channel corresponding to the position of the lower channel. The gold film layer, the single-crystal graphite layer, and the substrate layer are placed in a magnetic environment, and the two single-crystal graphite layers are respectively connected to the two poles of the power supply to form a circuit.

2. The mechanical memristor according to claim 1, characterized in that: The gold film layer has the same contact area with the upper ends of the two single-crystal graphite layers.

3. The mechanical memristor according to claim 2, characterized in that: The cross-sectional shape of the gold film layer is a rectangle or circle that is symmetrical from left to right.

4. The mechanical memristor according to claim 3, characterized in that: The lower channel is formed on the inner sides of the two opposing monocrystalline graphite layers, and the cross-sectional shape of the inner sides of the two opposing monocrystalline graphite layers is a sloping surface or a stepped shape with equal spacing.

5. The mechanical memristor according to claim 1, characterized in that: The thickness of the gold film layer is 100-500 nm, the length of the gold film layer is 10-30 μm, and the width of the gold film layer is 2-10 μm.

6. The mechanical memristor according to claim 1, characterized in that: The thickness of the single-crystal graphite layer is 500-2000 nm.

7. The mechanical memristor according to claim 1, characterized in that: A permanent magnet is disposed at the bottom of the substrate layer, and the permanent magnet provides a magnetic field perpendicular to the gold film layer.

8. The mechanical memristor according to claim 1, characterized in that: The substrate is made of silicon dioxide or aluminum oxide.

9. A method for fabricating a mechanical memristor, characterized in that, Includes the following steps: S1. Using a silicon dioxide substrate with a pre-grown single-crystal graphite layer as the basic template, a gold film layer is deposited on the surface of the single-crystal graphite layer in a vacuum thermal evaporation chamber at 1000℃ using thermal evaporation technology to form the first layered structure. S2. After the gold film layer is deposited, photoresist is uniformly spin-coated on the surface of the gold film layer to form a photoresist layer. The photoresist layer is patterned by photolithography and etching processes to obtain a second stacked structure with a lower channel. S3. A first sacrificial layer is deposited on the surface of the photoresist layer by magnetron sputtering, and a second sacrificial layer is deposited on the surface of the lower channel to obtain a third stacked structure. S4. The third stacked structure is cleaned using a photoresist stripping solution to remove the first sacrificial layer and photoresist layer on the surface of the gold film layer, resulting in the fourth stacked structure. S5. Using thermal evaporation technology, a second gold deposition is performed on the gold film layer and the second sacrificial layer on the surface of the fourth stacked structure in a vacuum thermal evaporation chamber at 1000°C to obtain the fifth stacked structure. S6. The surface of the fifth layer structure is processed by etching according to the target layout to obtain a plurality of first bridging structures that are mutually insulated and have independent functions. S7. Use a wet process to remove the second sacrificial layer on the first bridging structure to obtain a suspended second bridging structure; S8. Photoresist is uniformly spin-coated again on the upper surface of the second bridging structure to form a photoresist layer. The photoresist layer on the surface of the gold film layer is removed by photolithography. Then, the gold film layer is etched by wet etching to form a slider-type gold film layer. The gold film layer spans the upper ends of the single crystal graphite layers on both sides, and the length direction of the gold film layer is perpendicular to the extension direction of the lower channel. The middle area is a suspended upper channel and lower channel, thus obtaining the basic configuration of the mechanical memristor. S9. A permanent magnet is added to the bottom of the basic configuration, and an external power supply circuit is connected to the single-crystal graphite layers on both sides to obtain the mechanical memristor.

10. The method for preparing a mechanical memristor according to claim 9, characterized in that: In step S6, the process of etching the surface of the fifth layer structure according to the target layout to obtain multiple mutually insulated and independently functional first bridging structures includes: Determine the boundary lines of each of the first bridging structures according to the target layout; A photoresist layer is formed by uniformly spin-coating photoresist onto the surface of the fifth stacked structure. The boundary line is etched using an ion beam etching process to remove the gold film layer at the boundary line location. The boundary line is etched using a reactive ion etching process to remove the single-crystal graphite layer at the boundary line location, thereby obtaining multiple first bridging structures that are mutually insulated and have independent functions.

Images