Synaptic device based on two-dimensional ferroelectric material and preparation method of synaptic device

Abstract

The invention relates to the technical field of semiconductors, in particular to a synaptic device based on a two-dimensional ferroelectric material and a preparation method of the synaptic device. In order to solve the problem that a traditional silicon-based device cannot meet the requirement for continuous reduction of the size of the device, the novel synaptic device based on the two-dimensional ferroelectric material is provided as follows: an alpha-In2Se3 thin film layer is arranged on the upper surface of a Si substrate, an insulating dielectric layer is arranged on the upper surface of the alpha-In2Se3 thin film layer, and a part of the insulating dielectric layer is overlapped with a part of the alpha-In2Se3 thin film layer; the other part of the insulating dielectric layer is arranged on the upper surface of the Si substrate, the first metal electrode is arranged on the upper surface of one part of the insulating dielectric layer, the second metal electrode is arranged on the upper surface of the other part of the alpha-In2Se3 thin film layer, and the forbidden band width of the insulating dielectric layer is larger than 4 eV. The device is simple in structure and small in size, and has the characteristics of low power consumption and fast response.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a synaptic device based on two-dimensional ferroelectric materials and a preparation method thereof. Background Art

[0002] The explosive growth in information processing volume is placing ever-higher demands on circuit integration. To meet this demand, circuit integration continues to climb, driving device miniaturization. However, as device size continues to shrink, traditional silicon-based devices are encountering difficult-to-break bottlenecks. For example, challenging physical limitations like the short-channel effect have severely hampered their further development.

[0003] To overcome the functional limitations of traditional circuit components, address memory performance bottlenecks, and overcome the inherent flaws of the von Neumann architecture, scientists have proposed the memristor, an innovative device with memory capabilities. Memristors operate by dynamically changing their resistance through charge-regulated ion migration or defect structures within the material. However, due to the random formation of their conductive channels, device performance is unstable and parameter uniformity is poor between devices. Furthermore, during repeated erase and write cycles, memristors are susceptible to ion migration and conductive filament breakage, which limits their erase and write lifespan and hinders their practical application.

[0004] As a "potential stock" in the field of materials, two-dimensional ferroelectric materials have performed outstandingly in multiple key performance dimensions such as light, electricity, magnetism, and heat. They have attracted widespread attention from the scientific research and industrial communities, attracted many researchers to engage in related research, and become one of the current hot research directions in the field of materials science. α-In2Se3 is a two-dimensional ferroelectric material with room-temperature ferroelectricity, that is, α-In2Se3 exhibits ferroelectric polarization at room temperature, and its polarization direction can be flipped by external electric field excitation. With its programmable polarization switching characteristics, it has become the first choice for building artificial simulated synapses. Synaptic devices based on ferroelectric materials have significant advantages: at the same time, this two-dimensional ferroelectric material controls the polarization direction based on its spontaneous polarization characteristics, and its non-volatility in the multi-domain state makes its performance stable and uniform; in terms of power consumption, the power consumption of a single synaptic operation is less than 1f J, and the energy consumption advantage is outstanding in large-scale applications; in addition, with its rich physical properties, this two-dimensional ferroelectric material can achieve functional diversification, and the controllable polarization characteristics are more conducive to standardized manufacturing. Therefore, it is more competitive than memristors in practical applications. Therefore, it is urgent to propose a high-performance synaptic device based on two-dimensional ferroelectric materials (α-In2Se3). Summary of the Invention

[0005] In order to solve the problem that traditional silicon-based devices cannot adapt to the continuous reduction in device size requirements, the present invention provides a new synaptic device based on two-dimensional ferroelectric materials and a preparation method thereof.

[0006] The present invention is achieved by adopting the following technical solutions: A synaptic device based on two-dimensional ferroelectric materials includes a Si substrate, an α-In2Se3 thin film layer, an insulating dielectric layer, a first metal electrode, and a second metal electrode. The α-In2Se3 thin film layer is arranged on the upper surface of the Si substrate, the insulating dielectric layer is deposited on the upper surface of the α-In2Se3 thin film layer, the insulating dielectric layer and the α-In2Se3 thin film layer partially overlap to form a heterojunction, the first metal electrode is arranged on the upper surface of the overlapping portion of the insulating dielectric layer and the α-In2Se3 thin film layer, and the second metal electrode is arranged on the upper surface of the portion of the α-In2Se3 thin film layer where the insulating dielectric layer is not deposited, wherein the band gap width of the insulating dielectric layer is greater than 4eV.

[0007] Principle: Because the metal electrodes required for synaptic devices have a short shield length, when an external electric field is applied to the device, the charge on the metal electrodes compensates for the ferroelectric polarization, thereby affecting the device's on / off ratio. To address this issue, the present invention inserts an insulating dielectric layer with a relatively high bandgap between the first metal electrode and the α-In2Se3 thin film layer. This makes it difficult for electrons to cross the bandgap to form a conductive channel, thereby raising the Schottky barrier at the interface between the α-In2Se3 thin film layer and the insulating dielectric layer. This results in the device having highly pronounced on / off states, thereby improving the device's on / off ratio.

[0008] Furthermore, the thickness of the insulating dielectric layer is 3 nm, the thickness of the α-In2Se3 thin film layer is 180 nm, and the thickness of the first metal electrode and the second metal electrode are both 40 nm.

[0009] Furthermore, the insulating dielectric layer is a Si3N4 thin film layer, the band gap of the Si3N4 thin film layer is about 5 to 6.5 eV, and the electrode materials used for the first metal electrode and the second metal electrode are both Au.

[0010] Furthermore, the insulating dielectric layer is a SiO2 thin film layer, the band gap of the SiO2 thin film layer is about 9 eV, and the electrode materials used for the first metal electrode and the second metal electrode are both Au.

[0011] Furthermore, the device also includes a thin film encapsulation layer.

[0012] The above-mentioned method for preparing a synaptic device based on a two-dimensional ferroelectric material includes the following steps: 1) cleaning a Si substrate; 2) preparing an α-In2Se3 thin film by mechanical stripping; 3) transferring the α-In2Se3 thin film prepared in step 2) to a PDMS film, and then transferring the α-In2Se3 thin film to a Si substrate through a two-dimensional material transfer platform to form an α-In2Se3 thin film layer; 4) using photolithography technology (such as electron beam lithography, ultraviolet lithography, etc.) to define a deposition area for an insulating dielectric layer; 5) depositing an insulating dielectric layer in the defined deposition area, and ensuring that the deposited insulating dielectric layer is partially separated from the α-In2Se3 thin film layer. 6) patterning the deposited insulating dielectric layer using a lift-off process (such as a wet lift-off process or a dry lift-off process); 7) etching a first metal electrode pattern in the overlapping portion of the insulating dielectric layer and the α-In2Se3 thin film layer using a photolithography technique (such as electron beam lithography, ultraviolet lithography, etc.), and etching a second metal electrode pattern in the portion of the α-In2Se3 thin film layer where the insulating dielectric layer is not deposited; 8) depositing the first metal electrode and the second metal electrode using a thin film deposition process (such as thermal evaporation, magnetron sputtering, etc.); 9) patterning the deposited first metal electrode and the second metal electrode using a lift-off process (wet or dry) to complete device preparation.

[0013] Furthermore, a thin film encapsulation layer is generated on the device prepared in step 9) to complete the device encapsulation.

[0014] The beneficial effects of the present invention are as follows: 1) The device described in the present invention deposits an insulating dielectric layer between the first metal electrode and the α-In2Se3 thin film layer, making it difficult for electrons to cross the band gap to form a conductive channel, thereby raising the Schottky barrier between the interfaces, so that the device has extremely significant on and off states, and improves the switching ratio of the device; 2) In terms of preparation method, the present invention adopts a method of transferring α-In2Se3 thin film, depositing an insulating dielectric layer, and preparing a metal electrode, so as to better optimize the contact between the metal electrode and the material, reduce contact resistance and interface defects, and such a device has functions similar to biological synapses. By adjusting the external electric field excitation to change the conductivity state of the device, it can be used to simulate the weight change of biological synapses, thereby realizing the storage and processing of information, and then realizing neuromorphic computing; 3) The device has a simple structure, a small device size, low power consumption and fast response. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0017] Figure 1 Schematic diagram of the spontaneous polarization energy band of α-In2Se3 at room temperature; Figure 2 Schematic diagram of the energy band when a forward sweep voltage is applied to α-In2Se3, where the dotted line represents the previous state; Figure 3 Schematic diagram of the energy band when a reverse sweep voltage is applied to α-In2Se3, where the dotted line represents the previous state; Figure 4 Schematic diagram of the structure of the device of the present invention; Figure 5 Schematic diagram of energy bands when a forward scanning voltage is applied to the device of the present invention; Figure 6 Schematic diagram of energy bands when a reverse scanning voltage is applied to the device of the present invention; Figure 7 This is the application of the device of the present invention in the field of image recognition.

[0018] In the figure: 1-Si substrate, 2-α-In2Se3 thin film layer, 3-insulating dielectric layer, 4-first metal electrode, 5-second metal electrode. DETAILED DESCRIPTION

[0019] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0020] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all the embodiments.

[0021] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Example 1

[0022] like Figure 4As shown, a synaptic device based on two-dimensional ferroelectric material includes a Si substrate 1, an α-In2Se3 thin film layer 2, an insulating dielectric layer 3, a first metal electrode 4, and a second metal electrode 5. The α-In2Se3 thin film layer 2 is provided on the upper surface of the Si substrate 1, and the insulating dielectric layer 3 is deposited on the upper surface of the α-In2Se3 thin film layer 2. The insulating dielectric layer 3 partially overlaps with the α-In2Se3 thin film layer 2 to form a heterojunction. The first metal electrode 4 is provided on the overlapping portion of the insulating dielectric layer 3 and the α-In2Se3 thin film layer 2. The second metal electrode 5 is arranged on the upper surface of the α-In2Se3 thin film layer 2 where the insulating dielectric layer 3 is not deposited, wherein the insulating dielectric layer 3 is a Si3N4 thin film layer, the band gap width of the Si3N4 thin film layer is 5 to 6.5 eV, the thickness of the insulating dielectric layer 3 is 3 nm, the thickness of the α-In2Se3 thin film layer 2 is 180 nm, the electrode materials used for the first metal electrode 4 and the second metal electrode 5 are both Au and the thickness thereof are both 40 nm. In addition, the device also includes an Al2O3 thin film encapsulation layer.

[0023] Principle explanation: α-In2Se3 as a layered ferroelectric material has room temperature ferroelectricity, that is, it will spontaneously polarize at room temperature. Assuming that its polarization direction points to the drain end at room temperature, such as Figure 1 As shown in , at this time, the Schottky barrier at the drain end is higher and the Schottky barrier at the source end is lower; Figure 2 As shown in , when a forward sweep voltage is applied, that is, from -5V to 5V, the Schottky barrier height gradually changes and eventually completes the switching. The ferroelectric polarization direction points to the source end, the drain end barrier height is lower, and the source end barrier height is higher. Figure 3 As shown in the figure, when the reverse scanning voltage is applied, that is, scanning from 5V to -5V, the ferroelectric polarization direction points to the drain end again, so that the Schottky barrier height of the drain terminal gradually increases. This can fully illustrate the mechanism of regulating the Schottky barrier height based on ferroelectric polarization of α-In2Se3, which can excellently simulate the synaptic weight update process. The present invention mainly uses the characteristics of α-In2Se3 to achieve the conduction and cutoff of the device.

[0024] Because the metal electrodes required to fabricate synaptic devices have a short shield length, when an external electric field is applied to the device, the charge of the metal electrodes compensates for the ferroelectric polarization, thereby affecting the device's on / off ratio. To address this issue, the present invention inserts an insulating dielectric layer 3 between the first metal electrode 4 and the α-In2Se3 thin film layer 2. The insulating dielectric layer 3 selected here must have a high bandgap width, making it difficult for electrons to cross the bandgap to form a conductive channel. This increases the Schottky barrier height at the interface, giving the device a highly pronounced on / off state and improving the device's on / off ratio.

[0025] In order to verify the performance of the device of the present invention, the energy band change of the device was observed by applying forward scanning voltage and reverse scanning voltage. The energy band change of the device under the action of external electric field is as follows: Figure 5 As shown in FIG, when a forward scanning voltage is applied to the device, that is, from -5V to 5V, the ferroelectric polarization direction points to the insulating dielectric layer 3. At this time, the interface between the α-In2Se3 thin film layer 2 and the insulating dielectric layer 3 forms an accumulation of electrons on the side close to the α-In2Se3 thin film layer 2 under the action of polarization, which reduces the height of the Schottky barrier at the interface, forming a relatively low resistance, making it easier for electrons to transmit. At this time, the device is in the on state; Figure 6 As shown in the figure, when a reverse sweep voltage is applied, that is, from 5V to -5V, the polarization direction points to the α-In2Se3 thin film layer 2. At this time, the interface between the α-In2Se3 thin film layer 2 and the insulating dielectric layer 3 forms an accumulation of electrons on the side close to the insulating dielectric layer 3 due to polarization, which increases the Schottky barrier at the interface and forms a relatively high resistance, making it difficult for electrons to pass through the Schottky barrier. At this time, the device is in the off state. By comparing the low-resistance on-state under the forward sweep voltage and the high-resistance off-state under the reverse sweep voltage, it can be found that the resistance difference between the two is significantly increased. This significant resistance difference allows the device to switch between the on and off states more efficiently, thereby improving its switching performance, that is, increasing the switching ratio.

[0026] A method for preparing a synaptic device based on two-dimensional ferroelectric materials comprises the following steps: 1) Cleaning the Si substrate 1; 2) Prepare α-In2Se3 thin films using a mechanical stripping method: Use tape to sample the α-In2Se3 bulk sample, then use clean tape and the sampled tape to tear them apart, repeating the tearing process 3 to 4 times; 3) The α-In2Se3 thin film prepared in step 2) is transferred to a PDMS film, which is then transferred to a Si substrate 1 using a two-dimensional material transfer platform to form an α-In2Se3 thin film layer 2. The specific operation is as follows: the PDMS film is cut into multiple small pieces and the α-In2Se3 thin film is attached to the torn tape. The PDMS film with the α-In2Se3 thin film attached is then placed under a microscope for observation. An α-In2Se3 with a thickness of approximately 180 nm is selected, its position is marked, and the α-In2Se3 thin film is transferred to the Si substrate 1 using a dry transfer technique to form an α-In2Se3 thin film layer 2. 4) Using photolithography technology such as electron beam lithography to define a deposition area for the insulating dielectric layer 3; 5) Deposit the insulating dielectric layer 3, i.e., the Si3N4 thin film layer, in the designated deposition area, and ensure that the deposited Si3N4 thin film layer partially overlaps with the α-In2Se3 thin film layer 2 to form a heterojunction: First, prepare high-purity silicon powder and nitrogen, then wash the silicon powder in acetone and dry it, evenly place the pre-treated silicon powder in a crucible, then place the crucible in a high-temperature furnace, close the furnace door, and evacuate to 10 -3 Pa below to expel the air in the furnace, then introduce high-purity nitrogen to slightly increase the furnace pressure above atmospheric pressure. The furnace temperature is then raised to 1300-1400°C at a heating rate of 5-10°C / min. At this temperature, the silicon powder and nitrogen undergo a nitridation reaction to produce silicon nitride. During the reaction, the nitrogen is continuously introduced at a flow rate of 5-10 L / min to maintain the reaction atmosphere and provide an adequate nitrogen source. After the reaction is completed, heating is stopped and the sample in the furnace is allowed to slowly cool to room temperature in a nitrogen atmosphere. The silicon nitride powder generated by the reaction is finely ground and then acid-washed, washed with water, and dried to obtain pure silicon nitride powder. The dried silicon nitride powder is made into a target material, and the silicon nitride target is installed in the sputtering equipment using the sputtering method in physical vapor deposition (PVD). In a high vacuum environment, ion bombardment of the target material causes silicon nitride atoms or ions to be sputtered onto the Si substrate 1 and the upper surface of the α-In2Se3 thin film layer 2, ensuring that the deposited Si3N4 thin film layer partially overlaps with the α-In2Se3 thin film layer 2 to form a heterojunction; 6) Patterning the deposited Si3N4 thin film layer using a wet stripping process; 7) Using electron beam lithography, a first metal electrode pattern is etched in the overlapping portion of the Si3N4 thin film layer and the α-In2Se3 thin film layer 2, and a second metal electrode pattern is etched in the portion of the α-In2Se3 thin film layer 2 where the insulating dielectric layer 3 is not deposited; 8) Prepare the first metal electrode 4 and the second metal electrode 5 by thin film thermal evaporation deposition process, depositing electrode material Au to a thickness of about 40 nm; 9) Patterning the deposited first metal electrode 4 and the second metal electrode 5 using a wet stripping process to complete device fabrication; 10) Using an atomic layer deposition process, an Al2O3 thin film layer is formed on the device prepared in step 9) to complete device packaging. Specifically, trimethylaluminum is used as a precursor and adsorbed on the device surface to react; after the reaction, the byproduct CH4 is purged to remove it; water vapor is then used to carry out an adsorption reaction; after the reaction, the excess H2O and CH4 are purged again to form an Al2O3 thin film, and then an atomic layer deposition device is used to obtain an Al2O3 thin film layer with a thickness of approximately 30 to 31 nm. Example 2

[0027] A synaptic device based on two-dimensional ferroelectric materials includes a Si substrate 1, an α-In2Se3 thin film layer 2, an insulating dielectric layer 3, a first metal electrode 4, and a second metal electrode 5. The α-In2Se3 thin film layer 2 is arranged on the upper surface of the Si substrate 1, the insulating dielectric layer 3 is deposited on the upper surface of the α-In2Se3 thin film layer 2, and the insulating dielectric layer 3 and the α-In2Se3 thin film layer 2 partially overlap to form a heterojunction. The first metal electrode 4 is arranged on the upper surface of the overlapping portion of the insulating dielectric layer 3 and the α-In2Se3 thin film layer 2, and the second metal electrode 5 is arranged on the upper surface of the portion of the α-In2Se3 thin film layer 2 where the insulating dielectric layer 3 is not deposited. The insulating dielectric layer 3 is a SiO2 thin film layer with a band gap of 9eV, the insulating dielectric layer 3 is 3nm thick, and the α-In2Se3 thin film layer 2 is 180nm thick. The electrode materials used for the first metal electrode 4 and the second metal electrode 5 are both Au and their thicknesses are both 40nm. In addition, the device also includes an Al2O3 thin film encapsulation layer.

[0028] To verify the performance of the device, forward and reverse sweep voltages were applied to the device to observe its energy band changes. The energy band changes of the device under the applied electric field are shown below, which are basically consistent with the energy band changes in Example 1. This shows that the device can switch between the on and off states more efficiently, thereby improving its switching performance, that is, increasing the on / off ratio.

[0029] The method for preparing a synaptic device based on a two-dimensional ferroelectric material as described above comprises the following steps: 1) Cleaning the Si substrate 1; 2) Prepare α-In2Se3 thin films using a mechanical stripping method: Use tape to sample the α-In2Se3 bulk sample, then use clean tape and the sampled tape to tear them apart, repeating the tearing process 3 to 4 times; 3) The α-In2Se3 thin film prepared in step 2) is transferred to the PDMS film, and then the α-In2Se3 thin film is transferred to the Si substrate 1 via a two-dimensional material transfer platform to form an α-In2Se3 thin film layer 2. The specific operation is as follows: the PDMS film is cut into multiple small pieces and then the α-In2Se3 thin film is adhered to the torn tape. The PDMS film with the α-In2Se3 thin film adhered is then placed under a microscope for observation. An α-In2Se3 with a thickness of approximately 180 nm is selected and its position is marked. The α-In2Se3 thin film is then transferred to the Si substrate 1 via a dry transfer technique to form an α-In2Se3 thin film layer 2. 4) Using photolithography technology such as electron beam lithography to define a deposition area for the insulating dielectric layer 3; 5) Deposit the insulating dielectric layer 3, i.e., the SiO2 thin film layer, in the designated deposition area, and ensure that the deposited SiO2 thin film layer partially overlaps with the α-In2Se3 thin film layer 2 to form a heterojunction: First, prepare high-purity silicon powder and nitrogen, then wash the silicon powder in acetone and dry it, evenly place the pre-treated silicon powder in a crucible, then place the crucible in a high-temperature furnace, close the furnace door, and evacuate to 10 -3 Pa below to expel the air in the furnace, then introduce high-purity nitrogen to slightly increase the furnace pressure above atmospheric pressure. The furnace temperature is then raised to 1300-1400°C at a heating rate of 5-10°C / min. At this temperature, the silicon powder and nitrogen undergo a nitridation reaction to produce silicon nitride. During the reaction, the nitrogen is continuously introduced at a flow rate of 5-10 L / min to maintain the reaction atmosphere and provide an adequate nitrogen source. After the reaction is completed, heating is stopped and the sample in the furnace is allowed to slowly cool to room temperature in a nitrogen atmosphere. The silicon nitride powder generated by the reaction is finely ground and then acid-washed, washed with water, and dried to obtain pure silicon nitride powder. The dried silicon nitride powder is made into a target material, and the silicon nitride target is installed in the sputtering equipment using the sputtering method in physical vapor deposition (PVD). In a high vacuum environment, ion bombardment of the target material causes silicon nitride atoms or ions to be sputtered onto the Si substrate 1 and the upper surface of the α-In2Se3 thin film layer 2, ensuring that the deposited SiO2 thin film layer partially overlaps with the α-In2Se3 thin film layer 2 to form a heterojunction; 6) Patterning the deposited SiO2 thin film layer using a wet stripping process; 7) Using electron beam lithography, a first metal electrode pattern is etched in the overlapping portion of the SiO2 thin film layer and the α-In2Se3 thin film layer 2, and a second metal electrode pattern is etched in the portion of the α-In2Se3 thin film layer 2 where the insulating dielectric layer 3 is not deposited; 8) Prepare the first metal electrode 4 and the second metal electrode 5 by thin film thermal evaporation deposition process, depositing electrode material Au to a thickness of about 40 nm; 9) Patterning the deposited first metal electrode 4 and the second metal electrode 5 using a wet stripping process to complete device fabrication; 10) Using an atomic layer deposition process, an Al2O3 thin film layer is formed on the device prepared in step 9) to complete device packaging. Specifically, trimethylaluminum is used as a precursor and adsorbed on the device surface to react; after the reaction, the byproduct CH4 is purged to remove it; water vapor is then used to carry out an adsorption reaction; after the reaction, the excess H2O and CH4 are purged again to form an Al2O3 thin film, and then an atomic layer deposition device is used to obtain an Al2O3 thin film layer with a thickness of approximately 30 to 31 nm.

[0030] When simulating artificial synapses, multiple synaptic devices in the present invention are connected together to form a neural network, and the resistance value of the synaptic device is adjusted by applying voltage, thereby simulating the change in the synaptic connection strength between biological neurons. Figure 7 This device is used in the field of image recognition, where the input layer is the MNIST dataset, including 10 numbers: 1, 2, 3, 4, 5, 6, 7, 8, 9, and 0. Each image in the MNIST dataset is a handwritten number of 28×28 pixels. There are a total of 784 input neurons, and the output layer is 10 post-synaptic neurons, corresponding to the 10 input numbers. The input data is processed by the synaptic device and reaches the output layer. The synaptic device adjusts its synaptic weights according to the input data to realize the processing of the input data and realize neural system calculation.

[0031] The above description is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions have been made with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents; and such modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments, and they should all be included in the scope of protection of the claims.

Claims

1. A synaptic device based on two-dimensional ferroelectric material, characterized in that: The invention comprises a Si substrate (1), an α-In2Se3 thin film layer (2), an insulating dielectric layer (3), a first metal electrode (4), and a second metal electrode (5), wherein the α-In2Se3 thin film layer (2) is arranged on the upper surface of the Si substrate (1), the insulating dielectric layer (3) is deposited on the upper surface of the α-In2Se3 thin film layer (2), the insulating dielectric layer (3) and the α-In2Se3 thin film layer (2) partially overlap to form a heterojunction, the first metal electrode (4) is arranged on the upper surface of the overlapping portion of the insulating dielectric layer (3) and the α-In2Se3 thin film layer (2), and the second metal electrode (5) is arranged on the upper surface of the portion of the α-In2Se3 thin film layer (2) where the insulating dielectric layer (3) is not deposited, wherein the band gap width of the insulating dielectric layer (3) is greater than 4eV.

2. The synaptic device based on two-dimensional ferroelectric material according to claim 1, characterized in that: The thickness of the insulating dielectric layer (3) is 3 nm, the thickness of the α-In2Se3 thin film layer (2) is 180 nm, and the thickness of the first metal electrode (4) and the second metal electrode (5) are both 40 nm.

3. The synaptic device based on two-dimensional ferroelectric material according to claim 2, characterized in that: The insulating dielectric layer (3) is a Si3N4 thin film layer, and the electrode materials used for the first metal electrode (4) and the second metal electrode (5) are both Au.

4. The synaptic device based on two-dimensional ferroelectric material according to claim 2, characterized in that: The insulating dielectric layer (3) is a SiO2 thin film layer, and the electrode materials used by the first metal electrode (4) and the second metal electrode (5) are both Au.

5. The synaptic device based on two-dimensional ferroelectric material according to claim 4, characterized in that: The device also includes an Al2O3 thin film encapsulation layer.

6. A method for preparing a synaptic device based on two-dimensional ferroelectric materials, characterized in that: The steps include: 1) Cleaning the Si substrate (1); 2) Preparation of α-In2Se3 thin films by mechanical exfoliation; 3) transferring the α-In2Se3 thin film prepared in step 2) onto the PDMS film, and then transferring the α-In2Se3 thin film onto the Si substrate (1) through a two-dimensional material transfer platform to form an α-In2Se3 thin film layer (2); 4) Using photolithography technology to define the deposition area for the insulating dielectric layer (3); 5) depositing an insulating dielectric layer (3) in the designated deposition area, and ensuring that the deposited insulating dielectric layer (3) partially overlaps with the α-In2Se3 thin film layer (2) to form a heterojunction; 6) patterning the deposited insulating dielectric layer (3) using a lift-off process; 7) using photolithography technology, etching a pattern of a first metal electrode (4) in the overlapping portion of the insulating dielectric layer (3) and the α-In2Se3 thin film layer (2), and etching a pattern of a second metal electrode (5) in the portion of the α-In2Se3 thin film layer (2) where the insulating dielectric layer (3) is not deposited; 8) depositing the first metal electrode (4) and the second metal electrode (5) using a thin film deposition process; 9) Patterning the deposited first metal electrode (4) and the second metal electrode (5) using a lift-off process to complete device preparation.

7. The method for preparing a synaptic device based on a two-dimensional ferroelectric material according to claim 6, characterized in that: An atomic layer deposition process is used to generate a thin film encapsulation layer on the device prepared in step 9), thereby completing the device encapsulation.

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