Oxygen vacancy and ion heterogeneous integration of neural synaptic memristor and preparation method thereof

Abstract

The present invention discloses a neurosynaptic memristor with heterogeneous integration of oxygen vacancies and ions, and a method for preparing the same. The neurosynaptic memristor comprises: a substrate; a bottom electrode formed on the substrate; a functional layer formed on the bottom electrode and composed of an oxide layer and an ion gel layer, the oxide layer providing oxygen vacancy channels to achieve stable resistance transition behavior; and an ion gel layer providing mobile ions to simulate biological information transmission; and a top electrode formed on the functional layer. The device combines the high-speed, stable response of an oxygen vacancy memristor with the biomimetic information transmission capabilities of an ion memristor.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a neural synaptic memristor heterogeneously integrated with oxygen vacancies and ions and a preparation method thereof. Background Art

[0002] As a new type of memory cell, the memristor offers advantages such as high scalability, high integration density, high speed, low power consumption, and low operating voltage. Although first proposed in 1971, its feasibility was not experimentally confirmed until 2008. Subsequently, memristors with various structures and material compositions have been extensively studied in pursuit of even better memory performance.

[0003] On the other hand, the physical separation of storage and computing units in traditional computers has led to a bottleneck in the development of integrated circuit computing power. While miniaturization and increased integration density can improve computing power, this approach is unsustainable in the future as device size approaches physical limits. Therefore, the development of new electronic devices is needed to address this problem from a fresh perspective. Synaptic electronic devices, operating in a manner similar to the human brain, can overcome the limitations of physical structure, functionally integrating computing and storage, and providing a new path for energy-efficient computing.

[0004] Currently, neuromorphic memristors are mostly fabricated based on oxygen vacancy functional layers, demonstrating advantages such as strong durability and high speed. While this type of memristor can simulate brain-like computing functions to a certain extent, its operation relies on mobile electrons or vacancy defects, making it difficult to fully align with the working mode of mobile ions in biological organisms. However, ionic memristors suffer from poor stability and slow response speed, making them difficult to meet the requirements of high-speed and stable operation of computing units. Therefore, it is necessary to explore a heterogeneous integrated memristor that combines the oxygen vacancy conduction mechanism with the ion migration mechanism, simultaneously realizing the advantages of both functions, thereby improving device stability and operating speed while enhancing the device's biomimetic capabilities. Summary of the Invention

[0005] In order to solve the above problems, the present invention designs a neurosynaptic memristor with heterogeneous integration of oxygen vacancies and ions, which combines the high-speed and stable response of the oxygen vacancy channel of the oxide functional layer with the ion bionic migration function of the ion functional layer to achieve stable, high-speed, and bionic neurosynaptic function, and is used to construct a new type of memristor unit for neuromorphic computing.

[0006] The present invention provides a neurosynaptic memristor with heterogeneous integration of oxygen vacancies and ions, comprising: a substrate; a bottom electrode formed on the substrate; a functional layer formed on the bottom electrode, consisting of an oxide layer and an ion gel layer, wherein the oxide layer is used to provide an oxygen vacancy channel to achieve stable resistance transition behavior, and the ion gel layer is used to provide movable ions to simulate biological information transmission; and a top electrode formed on the functional layer.

[0007] In a neurosynaptic memristor heterogeneously integrated with oxygen vacancies and ions of the present invention, preferably, when a forward voltage is applied to the top electrode, the oxygen vacancies in the oxide layer move toward the bottom electrode and begin to accumulate at the bottom electrode. As the duration of the applied voltage increases, the oxygen vacancies gradually connect the bottom electrode and the ion gel layer to form a conductive channel; on the other hand, the ions in the ion gel layer gradually migrate toward the bottom electrode under the action of the forward voltage, and when the ions reach the bottom of the ion gel layer, they connect to the top of the oxide layer; as the voltage is further applied, the ions can gradually accumulate and connect the top of the oxide layer with the top electrode, and with the help of the oxygen vacancy channel in the oxide layer, a continuous conductive channel is finally formed between the top electrode and the bottom electrode, thereby reducing the resistance state of the memristor and converting the device from a high-resistance state to a low-resistance state.

[0008] In the oxygen vacancy and ion heterogeneously integrated neurosynaptic memristor of the present invention, preferably, when a negative voltage is applied to the top electrode, the ion conductive channel in the ion gel layer and the oxygen vacancy conductive channel in the oxide layer are broken, resulting in the absence of a continuous current transfer channel between the top electrode and the bottom electrode of the device, the resistance of the device becomes higher, and the device changes from a low-resistance state to a high-resistance state.

[0009] In the oxygen vacancy and ion heterogeneously integrated neurosynaptic memristor of the present invention, preferably, the oxide layer is HfO2, Ta2O5 or Al2O3.

[0010] In the oxygen vacancy and ion heterogeneous integrated neural synaptic memristor of the present invention, preferably, the gel solute ions in the ion gel layer are Li + 、Na + , Ca 2+ , K + One or a combination thereof, the gel solvent is one or a combination of PEO, PI, PVA, PVP.

[0011] The present invention also discloses a method for preparing a neural synaptic memristor with heterogeneous integration of oxygen vacancies and ions, comprising the following steps: forming a bottom electrode on a substrate; forming an oxide layer and an ion gel layer as functional layers on the bottom electrode, wherein the oxide layer is used to provide an oxygen vacancy channel to achieve stable resistance transition behavior, and the ion gel layer is used to provide movable ions to simulate biological information transmission; and forming a top electrode on the functional layer.

[0012] In the preparation method of a neural synaptic memristor with heterogeneous integration of oxygen vacancies and ions of the present invention, preferably, when a forward voltage is applied to the top electrode, the oxygen vacancies in the oxide layer move toward the bottom electrode and begin to accumulate at the bottom electrode. As the duration of the applied voltage increases, the oxygen vacancies gradually connect the bottom electrode and the ion gel layer to form a conductive channel; on the other hand, the ions in the ion gel layer gradually migrate toward the bottom electrode under the action of the forward voltage, and when the ions reach the bottom of the ion gel layer, they connect with the top of the oxide layer; as the voltage is further applied, the ions can gradually accumulate and connect the top of the oxide layer with the top electrode, and with the help of the oxygen vacancy channel in the oxide layer, a continuous conductive channel is finally formed between the top electrode and the bottom electrode, thereby achieving a reduction in the resistance state of the memristor, and the device changes from a high-resistance state to a low-resistance state.

[0013] In the preparation method of a neural synaptic memristor with heterogeneous integration of oxygen vacancies and ions of the present invention, preferably, when a negative voltage is applied to the top electrode, the ion conductive channel in the ion gel layer and the oxygen vacancy conductive channel in the oxide layer are broken, resulting in the absence of a continuous current transfer channel between the top electrode and the bottom electrode of the device, the resistance of the device becomes higher, and the device changes from a low-resistance state to a high-resistance state.

[0014] In the method for preparing a neural synaptic memristor with heterogeneous integration of oxygen vacancies and ions of the present invention, preferably, the oxide layer is HfO2, Ta2O5 or Al2O3.

[0015] In the preparation method of a neural synaptic memristor with heterogeneous integration of oxygen vacancies and ions of the present invention, preferably, the gel solute ions in the ion gel layer are Li + 、Na + , Ca 2+ , K + One or a combination thereof, the gel solvent is one or a combination of PEO, PI, PVA, PVP.

[0016] Beneficial effects:

[0017] (1) Bionic neurosynaptic memristor devices are of great value in realizing brain-like efficient neuromorphic computing. They can break the limitation of physical separation between computing units and storage units in traditional computing devices and realize the functions of memory and microprocessor in the same module.

[0018] (2) Compared with traditional pure oxide memristors and ionic memristors, the oxide functional layer and the ionic functional layer are heterogeneously integrated here, so that the memristor has both the high-speed and stable response of the oxygen vacancy memristor and the bionic information transmission function of the ionic memristor.

[0019] (3) Heterogeneous integration can provide a new direction for chip development in the post-Moore era, allowing the same device unit to have the advantages of multiple device units at the same time, greatly improving the reliability and performance of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Flowchart of the preparation method of synaptic memristor with heterogeneous integration of oxygen vacancies and ions.

[0021] Figure 2 It is a schematic diagram of the device structure after the bottom electrode is formed.

[0022] Figure 3 It is a schematic diagram of the device structure after the oxide layer is formed.

[0023] Figure 4 Schematic diagram of the device structure after the ion gel layer is formed.

[0024] Figure 5 Schematic diagram of the device structure after the top electrode is formed.

[0025] Figure 6 Schematic diagram of the working principle of the neural synaptic memristor with heterogeneous integration of oxygen vacancies and ions. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be noted that the terms "upper," "lower," "vertical," and "horizontal," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In addition, many specific details of the present invention are described below, such as device structure, materials, dimensions, processing techniques, and technologies, to facilitate a clearer understanding of the present invention. However, as will be appreciated by those skilled in the art, the present invention may be practiced without following these specific details. Unless otherwise noted below, various components of the device may be constructed from materials known to those skilled in the art, or materials with similar functions developed in the future may be used.

[0029] Figure 1 This is a flow chart of the preparation method of the neural synaptic memristor with heterogeneous integration of oxygen vacancies and ions. Figure 1 As shown, the following steps are included:

[0030] Step S1: Prepare a 2 cm x 2 cm silicon wafer as the substrate 100 for the oxygen vacancy and ion heterogeneously integrated neurosynaptic memristor. Ultrasonic cleaning is performed using acetone, ethanol, and deionized water for 5 minutes each. The substrate can also be muscovite, sapphire, or glass.

[0031] Step S2, using electron beam evaporation to prepare a 100nm thick Al bottom electrode 101 on the substrate 100, the resulting structure is as follows Figure 2 The electrode material may also be Au, Pt, TaN, etc.; and the thickness may range from 50 nm to 200 nm.

[0032] Step S3, using atomic layer deposition to grow a 20nm thick HfO2 film as the oxide layer 102 on the bottom electrode 101, the resulting structure is as follows Figure 3 As shown, it is used to provide oxygen vacancy channels to achieve stable resistance switching behavior. The oxide film layer is preferably HfO2, but can also be Ta2O5, Al2O3, etc.; the thickness range is 10nm-30nm.

[0033] Step S4, as Figure 4 As shown, a mixed solution of LiClO4 / PEO is spin-coated on the oxide layer 102, and then baked on a hot plate at a temperature of 60°C to 150°C for 2 minutes to 10 minutes to form a Li ion film as an ion gel layer 103, providing movable Li ions to simulate biological information transmission. Wherein, the pre-rotation speed during the spin coating process is 500 rpm to 2000 rpm, the duration is 5s to 15s, and the spinning speed is 4000 rpm to 5500 rpm, the duration is 40s to 180s. The ion gel layer is preferably a Li ion film, and the optional range is Li ion film, Na ion film, Ca ion film, etc.; the gel solute ions in the ion gel layer are Li + 、Na + , Ca 2+ , K +The gel solvents are polyethylene oxide (PEO), polyimide (PI), polyvinyl alcohol fiber (PVA), polyvinyl pyrrolidone (PVP), etc.

[0034] Step S5, using electron beam evaporation to grow a 80nm thick TaN top electrode 104 to complete the device preparation, the resulting structure is as follows Figure 5 The top electrode material may also be selected from Al, Au, etc.; the thickness is preferably 50nm to 150nm.

[0035] Figure 6 This is a schematic diagram of a single device cross section, showing the working principle of the neural synaptic memristor with heterogeneous integration of oxygen vacancies and ions, as shown in Figure 6 As shown in the figure, when a positive voltage is applied to the top electrode 104 of the neurosynaptic memristor with heterogeneous integration of oxygen vacancies and ions, the oxygen vacancies in the HfO2 film 102 move toward the bottom electrode 101 and begin to accumulate at the bottom electrode 101. As the voltage is applied for an increasing period of time, the oxygen vacancies gradually connect with the upper Li ion film 103 at the bottom electrode 101 to form a conductive channel (stage one). On the other hand, the ions in the Li ion film 103 gradually migrate toward the bottom electrode 101 under the action of the positive voltage. When the Li ions reach the bottom of the Li ion film 103, they can connect with the top of the HfO2 film 102. As the voltage is further applied, the Li ions can gradually accumulate and connect the top of the HfO2 film 102 with the top electrode 104. With the help of the oxygen vacancy channel in the HfO2 film 102, a continuous conductive channel is finally formed between the top electrode 104 and the bottom electrode 101 (stage two), thereby reducing the resistance state of the memristor and changing the device from a high-resistance state to a low-resistance state.

[0036] On the contrary, when a negative voltage is applied to the top electrode 104 of the device, the Li ion conductive channel in the Li ion film 103 and the oxygen vacancy conductive channel in the HfO2 film 102 will be broken, resulting in the lack of a continuous current transfer channel between the top electrode 104 and the bottom electrode 101 of the device, the resistance of the device becomes higher, and the device changes from a low-resistance state to a high-resistance state (stage three).

[0037] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with this technical field within the technical scope disclosed in the present invention should be covered by the scope of protection of the present invention.

Claims

1. A synaptic memristor heterogeneously integrated with oxygen vacancies and ions, characterized in that: include: substrate; a bottom electrode formed on the substrate; a functional layer formed on the bottom electrode, consisting of an oxide layer and an ion gel layer, wherein the oxide layer is used to provide oxygen vacancy channels to achieve stable resistance switching behavior, and the ion gel layer is used to provide mobile ions to simulate biological information transmission; a top electrode formed on the functional layer, Wherein, the gel solute ions in the ion gel layer are Li + 、Na + , Ca 2+ , K + One or a combination thereof, the gel solvent is one or a combination of PEO, PI, PVA, PVP.

2. The oxygen vacancy and ion heterogeneously integrated neural synaptic memristor according to claim 1, characterized in that: When a forward voltage is applied to the top electrode, the oxygen vacancies in the oxide layer move toward the bottom electrode and begin to accumulate at the bottom electrode. As the voltage is applied for an increasing period of time, the oxygen vacancies gradually connect the bottom electrode and the ion gel layer to form a conductive channel. On the other hand, the ions in the ion gel layer gradually migrate toward the bottom electrode under the action of the forward voltage. When the ions reach the bottom of the ion gel layer, they connect to the top of the oxide layer. As the voltage is further applied, the ions can gradually accumulate and connect the top of the oxide layer to the top electrode, and with the help of the oxygen vacancy channel in the oxide layer, a continuous conductive channel is finally formed between the top and bottom electrodes, thereby reducing the resistance state of the memristor and converting the device from a high-resistance state to a low-resistance state.

3. The oxygen vacancy and ion heterogeneously integrated neural synaptic memristor according to claim 1, characterized in that: When a negative voltage is applied to the top electrode, the ion conduction channel in the ion gel layer and the oxygen vacancy conduction channel in the oxide layer are broken, resulting in the lack of a continuous current transfer channel between the top electrode and the bottom electrode of the device. The resistance of the device becomes higher, and the device changes from a low-resistance state to a high-resistance state.

4. The oxygen vacancy and ion heterogeneously integrated neural synaptic memristor according to claim 1, characterized in that: The oxide layer is HfO2, Ta2O5 or Al2O3.

5. A method for preparing a synaptic memristor with heterogeneous integration of oxygen vacancies and ions, characterized in that: The following steps are involved: forming a bottom electrode on the substrate; forming an oxide layer and an ion gel layer as functional layers on the bottom electrode, wherein the oxide layer is used to provide an oxygen vacancy channel to achieve a stable resistance switching behavior, and the ion gel layer is used to provide mobile ions to simulate biological information transmission; forming a top electrode on the functional layer, Wherein, the gel solute ions in the ion gel layer are Li + 、Na + , Ca 2+ , K + One or a combination thereof, the gel solvent is one or a combination of PEO, PI, PVA, PVP.

6. The method for preparing a synaptic memristor with heterogeneous integration of oxygen vacancies and ions according to claim 5, characterized in that: When a forward voltage is applied to the top electrode, the oxygen vacancies in the oxide layer move toward the bottom electrode and begin to accumulate at the bottom electrode. As the voltage is applied for an increasing period of time, the oxygen vacancies gradually connect the bottom electrode and the ion gel layer to form a conductive channel. On the other hand, the ions in the ion gel layer gradually migrate toward the bottom electrode under the action of the forward voltage. When the ions reach the bottom of the ion gel layer, they connect to the top of the oxide layer. As the voltage is further applied, the ions can gradually accumulate and connect the top of the oxide layer to the top electrode, and with the help of the oxygen vacancy channel in the oxide layer, a continuous conductive channel is finally formed between the top and bottom electrodes, thereby reducing the resistance state of the memristor and changing the device from a high-resistance state to a low-resistance state.

7. The method for preparing a synaptic memristor with heterogeneous integration of oxygen vacancies and ions according to claim 5, characterized in that: When a negative voltage is applied to the top electrode, the ion conduction channel in the ion gel layer and the oxygen vacancy conduction channel in the oxide layer are broken, resulting in the lack of a continuous current transfer channel between the top electrode and the bottom electrode of the device. The resistance of the device becomes higher, and the device changes from a low-resistance state to a high-resistance state.

8. The method for preparing a synaptic memristor with heterogeneous integration of oxygen vacancies and ions according to claim 5, characterized in that: The oxide layer is HfO2, Ta2O5 or Al2O3.

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