Carbon-based field effect force-sensitive synaptic device and preparation method thereof

Abstract

The invention discloses a carbon-based field effect force-sensitive synaptic device and a preparation method thereof.The synaptic device comprises a carbon-based laminated conformal presynaptic film and a carbon-based field effect postsynaptic film which are arranged in an overlapped mode, and the carbon-based laminated conformal presynaptic film comprises a transmitter layer, a modified graphene floating gate layer and a dielectric layer which are sequentially arranged in a laminated mode; the carrier layer is a hexagonal boron nitride layer or an ionic gel layer, the carbon-based laminated cotype presynaptic membrane is of an inverted pyramid structure distributed in a plurality of arrays, a microstructure separation type interface is formed between the carrier layer and the channel layer, and when the dielectric layer receives action potential pulses, the highest site of the carrier layer is in contact with the channel layer. Artificial synaptic electronics and a heterojunction technology are combined, the force-sensitive floating gate is of an array type micro-separation structure, high integration of a sensing memory calculation function on a synaptic interface is achieved in the pressure sensing field based on the carbon-based field effect, force-electric signal conversion is achieved, and a biological nervous system composed of neurons and synapses can be simulated.

Description

Technical Field

[0001] The present invention relates to the technical field of microelectronic device technology, and in particular to a force-sensitive flexible synaptic device based on carbon-based field effect and a preparation method thereof. Background Art

[0002] At present, the development of artificial intelligence is limited by the "von Neumann storage wall bottleneck". The storage unit and the computing unit are physically separated, the amount of calculation is large, the energy consumption is high, and the timeliness is low. In the era of information explosion, the demand for the development of artificial intelligence is hindered. The development of the "sensing storage and computing integrated system" can integrate sensing, storage and computing units into one to break the bottleneck of the separation of each unit in the traditional architecture, which will reduce the processing of redundant data, greatly reduce computer power consumption, and speed up processing timeliness.

[0003] Flexible electronic skin is a new type of flexible sensor system that mimics human skin. By using electronic devices to mimic human skin, this type of flexible sensing system has the characteristics and functions of human skin. It has the characteristics of connectivity, low power consumption, and multi-functions, and can be widely used in medical health, intelligent robots and other fields. However, the neuromorphic functions of skin-like sensing systems such as flexible electronic skin are realized through back-end device circuits. In contrast, human skin is a multi-layer structure that not only has receptors to sense environmental changes, but also has synaptically connected neurons to achieve edge storage and processing. Therefore, the scientific and technological challenges faced by skin-like neuromorphic tactile sensing materials and devices are: how to achieve a high degree of integration of the sensing-storage-computing functions at the flexible device level.

[0004] At present, the patent with the announcement number "CN115241320A" discloses a bionic synaptic transistor and its preparation method and application. The bionic synaptic transistor includes a substrate, a source electrode and a drain electrode, a channel layer, a charge trapping tunneling layer, a photosensitive layer and a passivation layer stacked in sequence from bottom to top, which can realize the memory function of photoelectric signals and the recognition function of input images, imitating the visual recognition of images by organisms.

[0005] There is also a patent with the announcement number "CN117525199A" that discloses a heterojunction sensing storage computing device and its preparation method, the heterojunction sensing storage computing device includes: substrate, back gate electrode, first gate dielectric layer / second gate dielectric layer / third gate dielectric layer stack, one-dimensional nanowire, two-dimensional layered semiconductor material (overlapped with the one-dimensional nanowire to form a one-dimensional and two-dimensional heterojunction as a channel layer), source electrode and drain electrode. The perception, storage and computing functions of information are integrated in the same device unit, the photoelectric perception range and sensitivity of the device are improved, and the storage and computing integrated application of information perception capabilities in the visible and near-infrared bands is realized.

[0006] The above-mentioned existing patents have achieved the integrated integration of sensing, storage and computing in devices to a certain extent, but they are all related to the fields of vision and optoelectronics, and the manufacturing process is relatively complex. The application of sensing, storage and computing functions at the level of pressure sensor devices still needs to be continuously explored. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a carbon-based field-effect force-sensitive synaptic device, which can utilize the charge transfer and storage characteristics of the carbon-based multilayer heterostructure, and combine the force sensitivity and gate control characteristics of the microstructure electrode to achieve a high degree of integration of the sensing-storage-computing functions at the interface of the synaptic device; the technical problem to be solved by the present invention also includes providing a method for preparing a carbon-based field-effect force-sensitive synaptic device, which enables the prepared carbon-based field-effect force-sensitive synaptic device to form a heterojunction stack and a microstructure separation interface.

[0008] In order to solve the above technical problems, in the first aspect, the carbon-based field-effect force-sensitive synaptic device provided by the present invention adopts the following technical solutions:

[0009] A carbon-based field-effect force-sensitive synaptic device comprises an overlapping carbon-based laminated conformal presynaptic membrane and a carbon-based field-effect postsynaptic membrane, wherein the carbon-based field-effect postsynaptic membrane comprises a channel layer, a source electrode and a drain electrode formed at both ends of the channel layer; the carbon-based laminated conformal presynaptic membrane comprises a transmitter layer, a modified graphene floating gate layer and a dielectric layer which are sequentially laminated, wherein the transmitter layer is a hexagonal boron nitride layer or an ion gel layer, and the carbon-based laminated conformal presynaptic membrane presents a plurality of inverted pyramid structures distributed in an array, a microstructure separation interface is formed between the transmitter layer and the channel layer, and when the dielectric layer receives an action potential pulse, the highest point of the transmitter layer can contact the channel layer.

[0010] By adopting the above technical solution, the transfer layer, the modified graphene floating gate layer and the dielectric layer form a heterojunction stack. The hexagonal boron nitride layer is used as the transfer layer. The wide bandgap characteristics and large electron affinity of the hexagonal boron nitride enable it to form a higher tunneling barrier in the heterostructure, which can effectively curb the occurrence of direct tunneling current, so that the transfer layer and the dielectric layer form a stable insulating layer around the modified graphene floating gate layer while enabling the transfer of charge, so as to effectively isolate the floating gate to prevent the leakage of the charge stored in the modified graphene floating gate layer. The charge in the channel layer will enter the modified graphene floating gate layer through the transfer layer under the action of the external electric field, and be stored in the modified graphene floating gate layer (see Figure 1). After the dielectric layer receives the action potential pulse, the entire carbon-based laminated conformal presynaptic membrane is deformed, the highest potential of the transmitter layer contacts the channel layer, and part of the charge accumulated in the modified graphene floating gate layer returns to the channel layer through the transmitter layer and is exported for calculation and processing, realizing force-electric conversion and the transmission of neurotransmitters (free electrons); and the charge accumulated in the modified graphene floating gate layer utilizes the nonlinear relationship between pressure and tunneling current to realize the nonlinear force-sensitive synaptic memory process, and finally realizes the high integration of the sensing-storage-computing function at the interface of the synaptic device.

[0011] Moreover, the excellent surface quality of hexagonal boron nitride can not only significantly reduce interface defects and thus reduce leakage current, but also ensure the ideal flatness of the heterojunction interface, optimize carrier transport, improve charge transfer efficiency, and improve the sensitivity of flexible synaptic devices to pressure.

[0012] The ion gel layer is used as the transporter layer. The polymers that make up the ion gel are mostly cross-linked mesh-like colloidal block copolymers. The ionic liquid in the polymer copolymer will stably exist in the ion gel mesh structure in the form of anions and cations. However, under the action of an external electric field, the local movement of ions between the polymer chain and the ion coordination site produces the migration of anions and cations, thereby producing an uneven charge distribution inside the ion gel. The anions and cations are stacked at both ends of the dielectric layer interface to form a double electric layer (see Figure 2 ), so the ion gel can transfer the action potential pulses received by the dielectric layer to the channel layer for calculation and processing through the movement of charged ions, realizing force-electricity conversion and the transmission of neurotransmitters (charged ions). At the same time, the ion gel can form a stable insulating layer with the dielectric layer around the modified graphene floating gate layer, effectively isolating the floating gate to prevent the leakage of charges stored in the modified graphene floating gate layer, so that the charges accumulated in the modified graphene floating gate layer can use the nonlinear relationship between pressure and double-layer ion flow to realize the nonlinear force-sensitive synaptic memory process, and finally realize the high integration of the sensing-storage-computing function at the interface of the synaptic device.

[0013] In addition, the carbon-based laminated conformal presynaptic membrane is distributed in multiple arrays of inverted pyramid structures, which increases compressibility and stress concentration to achieve a significant change in the distance between the two electrodes under low pressure, thereby generating a large change in the electrical signal and significantly improving the sensitivity of the pressure sensor. A microstructure separation interface is formed between the transmitter layer and the channel layer, which can improve the non-volatility of the charge in the modified graphene floating gate layer, further strengthening the memory process.

[0014] The present invention prepares a synaptic device by combining artificial synaptic electronics with heterojunction technology. The force-sensitive floating gate of the entire synaptic device is an array-type micro-separation structure, and a variety of carbon-based materials are rationally integrated. Based on the carbon-based field effect, the sensing, storage and computing functions in the pressure sensing field are highly integrated at the synaptic interface. It not only realizes force-to-electric signal conversion, but also has the memory, learning and training functions of neurons. It can simulate the biological nervous system composed of neurons and synapses, so that the synaptic device has the characteristics of parallelism, low power consumption, fault tolerance, self-learning and robustness. It has the potential to overcome the traditional von Neumann bottleneck and create a new paradigm to deal with complex problems such as pattern recognition, image classification, decision-making and associative learning.

[0015] Optionally, a side surface of the dielectric layer away from the modified graphene floating gate layer is covered with a top gate layer, and a material of the top gate layer is a carbon nanocomposite material.

[0016] By adopting the above technical solution, the carbon nanocomposite material enables the top gate layer to convert the pressure exerted on the flexible synaptic device into action potential pulses, thereby driving the entire weighted and calculated process and realizing the parallel processing of distributed pressure.

[0017] Optionally, the material of the dielectric layer is at least one of boron nitride and hafnium oxide.

[0018] By adopting the above technical solution, boron nitride and hafnium oxide both have excellent insulation properties, which can effectively prevent the leakage of charges stored in the modified graphene floating gate layer and ensure the force-electric conversion process and memory process of the synaptic device.

[0019] Optionally, the channel layer is formed by integrating carbon nanotubes on a flexible substrate.

[0020] By adopting the above technical solution, a flexible substrate is used as the basic substrate of the synaptic device, and carbon nanotubes are integrated on the flexible substrate to obtain a channel layer. This allows the channel layer to have high sensitivity to electrical signals and obtain a flexible synaptic device that is close to bionic human skin.

[0021] Optionally, the method for preparing the ion gel comprises the following steps:

[0022] Polyethylene oxide, lithium perchlorate and methanol in a mass fraction ratio of 0.1:(0.01-0.015):(3-5) are prepared to obtain a mixed solution, the mixed solution is fully stirred, the mixed solution is centrifuged, and the supernatant is taken to obtain an ion gel.

[0023] By adopting the above technical scheme, the ion gel prepared above can make anions and cations stably exist in the ion gel network structure, and make the migration of anions and cations more sensitive to the external electric field, so as to further enhance the non-volatility of the charge in the modified graphene floating gate layer, strengthen the memory process, and further improve the sensitivity of pressure sensing of the synaptic device.

[0024] In a second aspect, the method for preparing the carbon-based field-effect force-sensitive synaptic device provided by the present invention adopts the following technical solution:

[0025] A method for preparing a carbon-based field-effect force-sensitive synaptic device comprises the following steps:

[0026] A mold having an array of multiple inverted pyramid structure grooves is prepared, and the mold is placed in a reaction chamber, so that the temperature of the reaction chamber is maintained at 900-1100° C. and in a H2 atmosphere with a flow rate of 9-11 sccm and a vacuum environment of 0.01-0.2 Pa;

[0027] A borohydrin volatile is introduced into the reaction chamber to grow a transfer layer on the inner surface of the mold; a mixed gas is introduced into the reaction chamber, wherein the mixed gas includes methane, ammonia and an inert gas at a flow rate ratio of 10: (0.01-3): (190-210), and a modified graphene floating gate layer is grown on the surface of the transfer layer;

[0028] Continue to introduce borohydrazine volatiles into the reaction chamber to deposit a dielectric layer on the modified graphene floating gate layer; take the mold out of the reaction chamber, pour a carbon nanocomposite material on the surface of the dielectric layer, and obtain a top gate layer after curing, that is, prepare a carbon-based laminated conformal presynaptic membrane;

[0029] The carbon-based laminated conformal presynaptic membrane is transferred from the mold to a temporary substrate for storage. When in use, the carbon-based laminated conformal presynaptic membrane and the carbon-based field effect postsynaptic membrane are aligned and assembled, and then the temporary substrate is removed to obtain a carbon-based field effect force-sensitive synaptic device.

[0030] By adopting the above technical solution and the above steps, a stable heterojunction stack can be formed between the hexagonal boron nitride layer, the modified graphene floating gate layer and the dielectric layer, and a microstructure separation interface can be formed between the transfer layer and the channel layer. In addition, by doping ammonia, the graphene is subjected to n-type nitrogen doping modification treatment, so that the formed modified graphene floating gate layer is essentially a mixed film of carbon atoms and nitrogen atoms, so that the modified graphene floating gate layer has better mechanical properties and can form higher localized charges, so that the synaptic device has better pressure sensing sensitivity.

[0031] Optionally, the operations of depositing the transfer layer and the dielectric layer include the following steps:

[0032] The reaction cavity is connected to a cavity filled with borazine, and an inert gas with a flow rate of 40-60 sccm is introduced into the reaction cavity from the cavity filled with borazine, so that the borazine volatiles enter the reaction cavity together with the inert gas flow and grow on the inner surface of the mold to form a transfer layer.

[0033] By adopting the above technical solution, by setting a certain flow rate of inert gas to pass through borazine, a suitable amount of borazine volatiles can be brought into the reaction chamber, so as to form a hexagonal boron nitride layer of uniform thickness on the mold.

[0034] Optionally, the number of deposited layers of hexagonal boron nitride in the transfer layer is 1-2 layers, and the number of deposited layers of boron nitride in the dielectric layer is 15-20 layers.

[0035] By adopting the above technical solution, the number of hexagonal boron nitride deposition layers of the dielectric layer grows to 15-20 layers, which can prevent the top gate layer from being conductive with the modified graphene floating gate layer, thereby causing the modified graphene floating gate layer to lose its ability to store charges and the nonlinear relationship between pressure and ion / electron flow, thereby losing its memory storage function.

[0036] Optionally, the operation of transferring the carbon-based laminated conformal presynaptic membrane to a temporary substrate specifically comprises the following steps:

[0037] Polydimethylsiloxane is spin-coated on the top gate layer, and after drying, a combination of temporary substrate / carbon-based laminated conformal presynaptic membrane / mold is obtained, and the combination is half-immersed in an etching solution, and the mold is ensured to be in contact with the etching solution, and the mold is etched away.

[0038] Optionally, the preparation of the mold includes the following steps:

[0039] The silicon wafer is cleaned to remove surface impurities, and photolithography is performed on the silicon wafer to expose periodic micrometer-scale square holes in the silicon dioxide layer of the silicon wafer; the square holes exposed in the silicon dioxide layer are then dry-etched, and after cleaning, the silicon wafer is wet-etched with potassium hydroxide and isopropyl alcohol to obtain multiple array-distributed inverted pyramid structure grooves on the silicon wafer.

[0040] By adopting the above technical solution, multiple inverted pyramid structures are first positioned by photolithography to expose the corresponding silicon dioxide layer, and then the square holes are efficiently etched and deepened by dry etching. Finally, potassium hydroxide is used to anisotropically etch the silicon wafer to form multiple regular pyramid tip structures.

[0041] In a third aspect, the method for preparing the carbon-based field-effect force-sensitive synaptic device provided by the present invention adopts the following technical solution:

[0042] A method for preparing a carbon-based field-effect force-sensitive synaptic device comprises the following steps:

[0043] A mold having an array of multiple inverted pyramid structure grooves is prepared, and the mold is placed in a reaction chamber, so that the temperature of the reaction chamber is maintained at 900-1100° C. and in a H2 atmosphere with a flow rate of 9-11 sccm and a vacuum environment of 0.01-0.2 Pa;

[0044] A modified graphene floating gate layer is grown on the inner surface of the mold, and then a dielectric layer is continuously grown on the inner surface of the modified graphene floating gate layer mold to form a dielectric layer; the mold is taken out of the reaction chamber, a carbon nanocomposite material is poured on the surface of the dielectric layer, and a top gate layer is obtained after curing;

[0045] Combining the top gate layer with a temporary substrate, removing the mold, coating the surface of the modified graphene floating gate layer with ion gel and curing it to form a transmitter layer, thereby obtaining a carbon-based laminated conformal presynaptic membrane;

[0046] When in use, the carbon-based laminated conformal presynaptic membrane and the carbon-based field effect postsynaptic membrane are aligned and assembled, and then the temporary substrate is removed to obtain a carbon-based field effect force-sensitive synaptic device.

[0047] By adopting the above technical scheme and the above steps, a stable heterojunction stack can be formed between the ion gel-based transfer layer, the modified graphene floating gate layer and the dielectric layer, artificial synaptic electronics and heterojunction technology are combined, the overall structure of the synaptic device adopts a separate design, and a variety of carbon-based materials such as carbon nanocomposites, graphene, and carbon nanotubes are rationally integrated, and based on the carbon-based field effect in the field of pressure sensing, a high degree of integration of sensing, storage, and computing functions at the synaptic interface is achieved.

[0048] In summary, the present invention includes at least one of the following beneficial technical effects:

[0049] 1. Hexagonal boron nitride or ion gel can form a stable insulating layer with the dielectric layer around the modified graphene floating gate layer, effectively isolating the floating gate to prevent the leakage of charges stored in the modified graphene floating gate layer, so that the charges accumulated in the modified graphene floating gate layer can use the nonlinear relationship between pressure-double layer ion flow or pressure-tunneling electron flow to realize the nonlinear force-sensitive synaptic memory process, and finally realize the high integration of sensing-storage-computing functions at the interface of synaptic devices;

[0050] 2. The carbon-based laminated conformal presynaptic membrane is distributed in multiple arrays of inverted pyramid structures, which increases compressibility and stress concentration to achieve a significant change in the distance between the two electrodes under low pressure, thereby generating a large change in the electrical signal and significantly improving the sensitivity of the pressure sensor. A microstructure separation interface is formed between the transmitter layer and the channel layer, which can improve the non-volatility of the charge in the modified graphene floating gate layer, further strengthening the memory process.

[0051] 3. Synaptic devices are prepared by combining artificial synaptic electronics with heterojunction technology. The overall structure of the synaptic device adopts a separate design and rationally uses a variety of carbon-based materials for integration. Based on the carbon-based field effect, the sensing, storage and computing functions in the field of pressure sensing are highly integrated at the synaptic interface. Not only does it realize the force-to-electric signal conversion, but it also has the memory, learning and training functions of neurons, simulating the biological nervous system composed of neurons and synapses, so that the synaptic device has the characteristics of parallelism, low power consumption, fault tolerance, self-learning and robustness. It has the potential to overcome the traditional von Neumann bottleneck and create a new paradigm to deal with complex problems such as pattern recognition, image classification, decision-making and associative learning. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of the physical mechanism of the carbon-based field-effect force-sensitive synaptic device (neurotransmitters are electrons) of the present invention.

[0053] Figure 2 It is a schematic diagram of the physical mechanism of the carbon-based field-effect force-sensitive synaptic device (neurotransmitters are ions) of the present invention.

[0054] Figure 3 This is a block diagram for realizing the sensing, storage and computing functions of the carbon-based field-effect force-sensitive synaptic device of the present invention.

[0055] Figure 4 It is a schematic structural diagram of the carbon-based field-effect force-sensitive synaptic device of the present invention.

[0056] Figure 5 It is a schematic diagram of the pressure sensing principle of the carbon-based field-effect force-sensitive synaptic device of the present invention.

[0057] Figure 6 It is a flow chart of the method for preparing the carbon-based field-effect force-sensitive synaptic device (the transmitter layer is a hexagonal boron nitride layer) of the present invention.

[0058] Explanation of the reference numerals: 1. carbon-based laminated conformal presynaptic membrane; 11. transmitter layer; 12. modified graphene floating gate layer; 13. dielectric layer; 14. top gate layer; 2. carbon-based field effect postsynaptic membrane; 21. channel layer; 22. source; 23. drain; 3. flexible substrate. DETAILED DESCRIPTION

[0059] The following is combined with Figure 4 The present invention is described in further detail.

[0060] The embodiment of the present invention discloses a carbon-based field effect force-sensitive synaptic device, referring to Figure 4 The carbon-based field-effect force-sensitive synaptic device includes a carbon-based laminated common presynaptic membrane 1, a carbon-based field-effect postsynaptic membrane 2 and a flexible substrate 3 which are stacked in sequence.

[0061] The carbon-based field effect postsynaptic membrane 2 includes a channel layer 21, and a source electrode 22 and a drain electrode 23 are formed at two ends of the channel layer 21. The channel layer 21 is formed by integrating carbon nanotubes (CNTs) on a flexible substrate 3.

[0062] The carbon-based laminated conformal presynaptic membrane 1 includes a transmitter layer 11, a modified graphene floating gate layer 12 and a dielectric layer 13 which are sequentially laminated. The transmitter layer 11 is a hexagonal boron nitride layer or an ion gel layer. The entire carbon-based laminated conformal presynaptic membrane 1 presents a plurality of array-distributed inverted pyramid structures. A microstructure separation interface is formed between the transmitter layer 11 and the channel layer 21. When the carbon-based laminated conformal presynaptic membrane 1 is deformed by force, the highest point of the transmitter layer 11 can contact the channel layer 21. The dielectric layer 13 is covered with a top gate layer 14 on one side away from the modified graphene floating gate layer 12. The material of the top gate layer 14 is a carbon nanocomposite material, and the carbon nanocomposite material is a graphene slurry and / or a carbon nanotube slurry.

[0063] Part 1: The transfer layer is a hexagonal boron nitride layer

[0064] Embodiment 1:

[0065] A method for preparing a carbon-based field-effect force-sensitive synaptic device comprises the following steps:

[0066] Preparation of mold:

[0067] First, the silicon wafer was ultrasonically cleaned in deionized water, acetone and alcohol for 15 minutes each to remove surface impurities. After spin coating photoresist on the clean silicon wafer, it was placed on a hot plate and dried at 100°C for 10 minutes. After drying, it was exposed using a binary exposure machine and developed with a developer to form a square pattern. After the photolithography was completed, the periodic micrometer-scale square holes in the silicon dioxide layer on the silicon wafer were exposed.

[0068] First, use a RIE dry etcher (model PLASMALAB 133) to etch the exposed silicon dioxide, using trifluoromethane as the etching gas, to efficiently etch and deepen the square holes;

[0069] The photoresist on the surface of the sample is then cleaned with acetone and alcohol. The pyramid structure is obtained by anisotropic etching of the silicon wafer with potassium hydroxide (concentration of 10%). Adding isopropanol to the etching solution can improve the orderliness of the pyramid structure etching; after rinsing with deionized water and then blowing dry with a high-purity nitrogen gun, a mold with an array of multiple inverted pyramid structure grooves is obtained.

[0070] Preparation of carbon-based laminated conformal presynaptic membrane:

[0071] The mold is placed in the reaction chamber of the heating tube furnace, the heating tube furnace is evacuated to 0.1 Pa, and the heating tube furnace is heated to 1000° C. within 30 minutes. When the temperature reaches 1000° C., it is maintained for 10 minutes in a H2 atmosphere with a flow rate of 10 sccm, so that the temperature in the entire heating tube furnace is stabilized at 1000° C.;

[0072] The reaction chamber in the heating tube furnace is connected to a cavity containing borazine, a valve between the cavity containing borazine and the heating tube furnace is opened, and argon gas with a flow rate of 50 sccm is introduced into the cavity containing borazine, so that the borazine volatiles follow the inert gas flow into the reaction cavity, grow for 20 minutes, and grow to form a transfer layer on the inner surface of the mold;

[0073] The valve between the cavity containing borohydrazine and the heating tube furnace is closed, and a mixed gas is introduced into the reaction chamber of the heating tube furnace. The mixed gas includes methane with a flow rate of 10 sccm, ammonia with a flow rate of 2 sccm, and argon with a flow rate of 200 sccm. The growth is carried out for 10 minutes to grow a modified graphene floating gate layer on the surface of the transfer layer;

[0074] Then, the valve between the cavity containing borazine and the heating tube furnace is opened, and argon gas with a flow rate of 50 sccm is introduced into the cavity containing borazine, so that the borazine volatiles follow the inert gas flow into the reaction cavity and grow for 300 minutes to form a dielectric layer on the inner surface of the mold;

[0075] The mold is taken out from the reaction chamber, and graphene slurry is poured on the surface of the dielectric layer, and a top gate layer is obtained after heating and curing, that is, a carbon-based laminated conformal presynaptic membrane is prepared;

[0076] Polydimethylsiloxane is spin-coated on the top gate layer, and after drying, a combination of temporary substrate / carbon-based laminated conformal presynaptic membrane / mold is obtained, and the above combination is half-immersed in an etching solution, which is a potassium hydroxide solution with a concentration of 10%, to ensure that the mold is in contact with the etching solution, and the mold is corroded and removed.

[0077] Preparation of carbon-based field-effect postsynaptic membrane:

[0078] The carbon nanotube field effect transistor is prepared by using CMOS integration process technology on a flexible substrate (PET film) to obtain a channel layer, and a drain and a source are formed on both sides of the channel layer (the gate part can be played by a carbon-based laminated conformal presynaptic membrane).

[0079] Packaging of synaptic devices:

[0080] The resistive carbon-based laminated conformal presynaptic membrane and the carbon-based field effect postsynaptic membrane are stored separately. When in use, a laminating machine is used to align and package the carbon-based laminated conformal presynaptic membrane and the carbon-based field effect postsynaptic membrane, and then the polydimethylsiloxane temporary substrate is removed to obtain a carbon-based field effect force-sensitive synaptic device.

[0081] Embodiment 2:

[0082] A method for preparing a carbon-based field-effect force-sensitive synaptic device is different from that of Example 1 in that argon gas with a flow rate of 40 sccm is introduced into a cavity containing borazine.

[0083] Embodiment 3:

[0084] A method for preparing a carbon-based field-effect force-sensitive synaptic device is different from that of Example 1 in that argon gas with a flow rate of 60 sccm is introduced into a cavity containing borazine.

[0085] Embodiment 4:

[0086] A method for preparing a carbon-based field-effect force-sensitive synaptic device is different from that of Example 1 in that the flow rate ratio of methane, ammonia and inert gas in the mixed gas is 10:0.01:190.

[0087] Embodiment 5:

[0088] A method for preparing a carbon-based field-effect force-sensitive synaptic device is different from that of Example 1 in that the flow rate ratio of methane, ammonia and inert gas in the mixed gas is 10:3:210.

[0089] Comparative Example 1:

[0090] The difference from Example 1 is that the flow rate ratio of methane, ammonia and inert gas in the mixed gas is 10:5:200.

[0091] Comparative Example 2:

[0092] The difference from Example 1 is that the mold having an array of multiple inverted pyramid structure grooves is replaced by a silicon wafer that has not been treated as above.

[0093] Performance test method:

[0094] The sensitivity of Examples 1-5 and Comparative Example 1 was measured, and the results are shown in Table 1;

[0095] The sensitivity is calculated by the ratio of the relative change in source-drain current to the change in pressure:

[0096]

[0097] ΔI is the relative change of source-drain current;

[0098] ΔP is the ratio of pressure change;

[0099] I o is the source current.

[0100] Table 1:

[0101] <![CDATA[Sensitivity (*10^3 kPa -1 )]]> Example 1 1.2 Example 2 1.1 Example 3 1.0 Example 4 1.1 Example 5 1.0 Comparative Example 1 0.6 Comparative Example 2 0.3

[0102] Combining Examples 1-3 and Table 1, it can be seen that when argon is introduced within the flow rate range of the present invention, the sensitivity of the flexible synaptic device is within 10^3 kPa. -1 The above means that the pressure sensing sensitivity is excellent.

[0103] In combination with Example 1, Examples 4-5 and Comparative Example 1, the mixed gas was introduced within the flow rate ratio range of the present application, and the sensitivity of the obtained flexible synaptic device was within 10^3 kPa. -1 The above has excellent pressure sensing sensitivity.

[0104] It can be seen from Example 1, Comparative Example 2 and Table 1 that the array-type micro-separation structure between the transmitter layer and the channel layer in the present invention can significantly improve the sensitivity of the flexible synaptic device.

[0105] Part 2: The transporter layer is an ion gel layer

[0106] Embodiment 6:

[0107] A method for preparing a carbon-based field-effect force-sensitive synaptic device is different from that of Example 1 in that the preparation process of the carbon-based laminated conformal presynaptic membrane is different, as follows:

[0108] The mold is placed in the reaction chamber of the heating tube furnace, the heating tube furnace is evacuated to 0.1 Pa, and the heating tube furnace is heated to 1000° C. within 30 minutes. When the temperature reaches 1000° C., it is maintained for 10 minutes in a H2 atmosphere with a flow rate of 10 sccm, so that the temperature in the entire heating tube furnace is stabilized at 1000° C.;

[0109] A mixed gas is introduced into the reaction chamber of the heating tube furnace, wherein the mixed gas includes methane with a flow rate of 10 sccm, ammonia with a flow rate of 2 sccm, and argon with a flow rate of 200 sccm, and the growth is carried out for 10 minutes to grow a modified graphene floating gate layer on the inner surface of the mold;

[0110] The reaction chamber in the heating tube furnace is connected to a cavity filled with borazine, a valve between the cavity filled with borazine and the heating tube furnace is opened, and argon gas with a flow rate of 50 sccm is introduced into the cavity filled with borazine, so that the borazine volatiles follow the inert gas flow into the reaction cavity, grow for 300 minutes, and form a dielectric layer on the modified graphene floating gate layer; the mold is taken out of the reaction cavity, and graphene slurry is poured on the surface of the dielectric layer, and a top gate layer is obtained after heating and curing;

[0111] Polydimethylsiloxane is spin-coated on the top gate layer, and after drying, a combination of a temporary substrate / carbon-based laminated conformal presynaptic membrane / mold is obtained, and the above combination is half-immersed in an etching solution, and the mold is corroded and removed to expose the modified graphene floating gate layer, and an ion gel is coated on the surface of the modified graphene floating gate layer and cured to form a transmitter layer, thereby obtaining a carbon-based laminated conformal presynaptic membrane.

[0112] The preparation process of ion gel includes the following steps:

[0113] A mixed solution was prepared with polyethylene oxide, lithium perchlorate and methanol in a mass fraction ratio of 0.1:0.012:4, stirred at 45°C for 3 hours using a magnetic stirrer, and then the mixed solution was centrifuged at high speed using a centrifuge, and the supernatant was taken to obtain an ion gel.

[0114] Embodiment 7:

[0115] A method for preparing a carbon-based field-effect force-sensitive synaptic device is different from that of Example 6 in that the mass fraction ratio of polyethylene oxide, lithium perchlorate and methanol is 0.1:0.012:4.

[0116] Embodiment 8:

[0117] A method for preparing a carbon-based field-effect force-sensitive synaptic device is different from that of Example 6 in that the mass fraction ratio of polyethylene oxide, lithium perchlorate and methanol is 0.1:0.012:4.

[0118] Performance test method:

[0119] The sensitivity of Examples 6-8 was measured, and the results are shown in Table 2.

[0120] Table 2:

[0121] <![CDATA[Sensitivity (*10^3 kPa -1 )]]> Example 6 1.0 Example 7 0.9 Example 8 1.1

[0122] Combining Examples 6-8 and Table 1, it can be seen that the sensitivity of the flexible synaptic device prepared by preparing the ion gel within the mass fraction ratio range of the present invention is 0.9*10^3 kPa. -1 The above has excellent pressure sensing sensitivity.

[0123] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A carbon-based field-effect force-sensitive synaptic device, characterized in that: The invention comprises a carbon-based laminated conformal presynaptic membrane (1) and a carbon-based field effect postsynaptic membrane (2) which are overlapped, wherein the carbon-based field effect postsynaptic membrane (2) comprises a channel layer (21), a source electrode (22) and a drain electrode (23) formed at two ends of the channel layer (21); the carbon-based laminated conformal presynaptic membrane (1) comprises a transmitter layer (11), a modified graphene floating gate layer (12) and a dielectric layer (13) which are stacked in sequence, wherein the transmitter layer (11) is a hexagonal boron nitride layer or an ion gel layer, and the carbon-based laminated conformal presynaptic membrane (1) presents a plurality of inverted pyramid structures distributed in an array, a microstructure separation interface is formed between the transmitter layer (11) and the channel layer (21), and when the dielectric layer (13) receives an action potential pulse, the highest point of the transmitter layer (11) can contact the channel layer (21).

2. A carbon-based field-effect force-sensitive synaptic device according to claim 1, characterized in that: A side surface of the dielectric layer (13) away from the modified graphene floating gate layer (12) is covered with a top gate layer (14), and the material of the top gate layer (14) is a carbon nanocomposite material.

3. A carbon-based field-effect force-sensitive synaptic device according to claim 1, characterized in that: The channel layer (21) is formed by integrating carbon nanotubes on a flexible substrate (3).

4. A carbon-based field-effect force-sensitive synaptic device according to claim 1, characterized in that: The preparation method of the ion gel comprises the following steps: Polyethylene oxide, lithium perchlorate and methanol in a mass fraction ratio of 0.1:(0.01-0.015):(3-5) are prepared to obtain a mixed solution, the mixed solution is fully stirred, the mixed solution is centrifuged, and the supernatant is taken to obtain an ion gel.

5. A method for preparing a carbon-based field-effect force-sensitive synaptic device as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: A mold having an array of multiple inverted pyramid structure grooves is prepared, and the mold is placed in a reaction chamber, so that the temperature of the reaction chamber is maintained at 900-1100° C. and in a H2 atmosphere with a flow rate of 9-11 sccm and a vacuum environment of 0.01-0.2 Pa; A borohydride volatile is introduced into the reaction chamber to grow a transfer layer (11) on the inner surface of the mold; a mixed gas is then introduced into the reaction chamber, wherein the mixed gas comprises methane, ammonia and an inert gas at a flow rate ratio of 10:(0.01-3):(190-210), and a modified graphene floating gate layer (12) is grown on the surface of the transfer layer (11); Continue to introduce borohydrazine volatiles into the reaction chamber to deposit a dielectric layer (13) on the modified graphene floating gate layer (12); remove the mold from the reaction chamber, cast a carbon nanocomposite material on the surface of the dielectric layer (13), and obtain a top gate layer (14) after curing, thereby preparing a carbon-based laminated conformal presynaptic membrane; The carbon-based laminated conformal presynaptic membrane is transferred from the mold to a temporary substrate for storage. When in use, the carbon-based laminated conformal presynaptic membrane and the carbon-based field effect postsynaptic membrane (2) are aligned and assembled, and then the temporary substrate is removed to obtain a carbon-based field effect force-sensitive synaptic device.

6. The method for preparing a carbon-based field-effect force-sensitive synaptic device according to claim 5, characterized in that: The operations of depositing the transfer layer (11) and the dielectric layer (13) both include the following steps: The reaction cavity is connected to a cavity filled with borazine, and an inert gas with a flow rate of 40-60 sccm is introduced from the cavity filled with borazine into the reaction cavity, so that the borazine volatiles follow the inert gas flow into the reaction cavity and grow on the inner surface of the mold to form a transfer layer (11).

7. The method for preparing a carbon-based field-effect force-sensitive synaptic device according to claim 5, characterized in that: The number of deposited layers of hexagonal boron nitride in the transfer layer (11) is 1-2 layers, and the number of deposited layers of boron nitride in the dielectric layer (13) is 15-20 layers.

8. The method for preparing a carbon-based field-effect force-sensitive synaptic device according to claim 5, characterized in that: The operation of transferring the carbon-based laminated conformal presynaptic membrane to a temporary substrate specifically comprises the following steps: Polydimethylsiloxane is spin-coated on the top gate layer (14), and after drying, a combination of temporary substrate / carbon-based laminated conformal presynaptic membrane / mold is obtained, and the combination is half-immersed in an etching solution, and the mold is ensured to be in contact with the etching solution, and the mold is etched away.

9. The method for preparing a carbon-based field-effect force-sensitive synaptic device according to claim 5, characterized in that: The preparation of the mold comprises the following steps: The silicon wafer is cleaned to remove surface impurities, and photolithography is performed on the silicon wafer to expose periodic micrometer-scale square holes in the silicon dioxide layer of the silicon wafer; the square holes exposed in the silicon dioxide layer are then dry-etched, and after cleaning, the silicon wafer is wet-etched with potassium hydroxide and isopropyl alcohol to obtain multiple array-distributed inverted pyramid structure grooves on the silicon wafer.

10. A method for preparing a carbon-based field-effect force-sensitive synaptic device according to any one of claims 1 to 4, characterized in that: The following steps are involved: A mold having an array of multiple inverted pyramid structure grooves is prepared, and the mold is placed in a reaction chamber, so that the temperature of the reaction chamber is maintained at 900-1100° C. and in a H2 atmosphere with a flow rate of 9-11 sccm and a vacuum environment of 0.01-0.2 Pa; A modified graphene floating gate layer (12) is grown on the inner surface of the mold, and then a dielectric layer (13) is continuously grown on the inner surface of the modified graphene floating gate layer (12) mold; the mold is taken out of the reaction chamber, a carbon nanocomposite material is poured on the surface of the dielectric layer (13), and a top gate layer (14) is obtained after curing; The top gate layer (14) is combined with a temporary substrate, the mold is removed, and an ion gel is coated on the surface of the modified graphene floating gate layer (12) and cured to form a transmitter layer (11), thereby obtaining a carbon-based laminated conformal presynaptic membrane; When in use, the carbon-based laminated conformal presynaptic membrane and the carbon-based field effect postsynaptic membrane (2) are aligned and assembled, and then the temporary substrate is removed to obtain a carbon-based field effect force-sensitive synaptic device.

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