Fast ion conductor active electrode memristor functional layer material and preparation and application thereof

Abstract

The invention discloses a fast ion conductor active electrode memristor functional layer material and preparation and application thereof. The fast ion conductor active electrode memristor functional layer material comprises a fast ion conductor layer and an amorphous oxide layer which are stacked. The ionic conductivity of the fast ion conductor layer is greater than that of the amorphous oxide layer, the resistivity of the amorphous oxide layer is greater than that of the fast ion conductor layer, and the amorphous oxide layer contains an ion migration channel; the high ionic conductivity of the fast ion conductor is utilized, the resistance change voltage of the active metal electrode memristor is greatly reduced, the resistance state can be stably and slowly changed, the modulation effect on the on-off of the metal conductive filament is achieved, and the stability and consistency of the memristor are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of microelectronic devices, and in particular to a fast ion conductor active electrode memristor functional layer material and preparation and application thereof. Background Art

[0002] Memristors are considered to be the fourth passive basic circuit element in addition to resistors, capacitors, and inductors. The resistance of a memristor changes with the amount of charge flowing through it, and it can maintain its resistance state when the current is disconnected, thereby realizing a non-volatile information storage function. After studying the non-volatile information storage function of memristors, it has been found that they can be used in high-density information storage or non-volatile state logic operations. In addition, some memristors have the characteristic of continuously adjustable conductance, which allows them to be used as synaptic devices in brain-like neuromorphic computing. Memristors achieve the fusion of storage and computing in a single device, making them one of the basic devices for building a non-von Neumann computing architecture. At present, memristors based on the conductive filament theory have the advantages of simple structure, low power consumption, and fast read and write speed, making them one of the most promising storage technologies. However, the research on memristors has not been long, and there are still many problems to be solved. On the one hand, the migration of ions in the dielectric material of the memristor will form conductive filaments, and the connection and breakage of the conductive filaments will change the conductivity of the device. At present, most memristors have the problem of discrete distribution of operating voltage and high and low resistance states, which makes the consistency between devices (device to device) and electrical cycles (cycle to cycle) problematic, limiting the storage capacity of memristor memory chips, and also posing great challenges to the large-scale integration and circuit design of memristors. On the other hand, in the field of modern brain-like neuromorphic computing, the moment when the conductive filaments of memristors as synaptic elements are formed in the dielectric layer will cause a sudden increase in the device conductivity, which does not meet the requirement of brain-like simulation that the memristor conductivity can change continuously with the external electric field. The linearity of synaptic characteristics is generally poor, which also seriously restricts the research on peripheral circuits of artificial neural network chips, not only increasing the design cost, but also increasing the circuit area.

[0003] Therefore, it is necessary to provide a technical solution to improve the consistency of memristors and the linearity of synapses. Summary of the invention

[0004] In view of this, the present application provides a fast ion conductor active electrode memristor functional layer material and its preparation and application, which are used to solve the problem of how to improve the consistency of the memristor and the synaptic linearity.

[0005] In order to achieve the above technical objectives, this application adopts the following technical solutions: In the first aspect, the present application provides a fast ion conductor active electrode memristor functional layer material, including a stacked fast ion conductor layer and an amorphous oxide layer; the ionic conductivity of the fast ion conductor layer is greater than the ionic conductivity of the amorphous oxide layer, the resistivity of the amorphous oxide layer is greater than the resistivity of the fast ion conductor layer, and the amorphous oxide layer contains an ion migration channel.

[0006] Preferably, the chemical composition of the fast ion conductor layer includes a fast ion conductor material containing silver and / or copper ions, and the chemical composition of the amorphous oxide layer includes an amorphous metal oxide.

[0007] Preferably, the fast ion conductor material containing silver and / or copper ions is a sulfide containing silver and / or copper ions, and the metal elements in the amorphous metal oxide include one or more of Hf, Al, Ti, Ta, Cu, W, Ni, Zn, Zr, Fe, Mn and Nb.

[0008] In a second aspect, the present application provides a memristor unit comprising a fast ion conductor active electrode memristor functional layer material, including an inert electrode, an amorphous oxide layer, a fast ion conductor layer, and an active electrode stacked in sequence.

[0009] Preferably, the number of fast ion conductor layers is ≥1, and the number of amorphous oxide layers is ≥1.

[0010] Preferably, the thickness of the fast ion conductor layer is 5-200 nm, and the thickness of the amorphous oxide layer is 10-500 nm.

[0011] In a third aspect, the present application provides a method for preparing a memristor unit, comprising the following steps: Providing a substrate, and depositing an inert electrode on the surface of the substrate by using a physical vapor deposition process; Using magnetron sputtering technology, an amorphous oxide layer is pulse-deposited on the surface of the inert electrode; Depositing a fast ion conductor layer on the surface of the amorphous oxide layer by using a magnetron sputtering process; The active electrode pattern is prepared on the surface of the fast ion conductor layer by a photolithography process, and then the active electrode is deposited by a magnetron sputtering process. In a fourth aspect, the present application provides a modulation method of a memristor unit, comprising the following steps: S1. Applying a first external stimulus to the memristor unit causes metal cations in the fast ion conductor layer to migrate in the amorphous oxide layer to form conductive filaments; S2. withdrawing the first external excitation, so that the metal cations in step S1 are affected by the migration barrier and cannot migrate back to the fast ion conductor layer; S3. Apply a second external stimulus to migrate the metal cations in step S2 back to the fast ion conductor layer and disconnect the conductive filaments in the amorphous oxide layer.

[0012] Preferably, the positive and negative poles of the first external excitation and the second external excitation are opposite.

[0013] In a fifth aspect, the present application provides an application of a memristor unit in an artificial neural network chip.

[0014] The beneficial effects of this application are as follows: The memristor unit of the present application includes a fast ion conductor layer and an amorphous oxide layer. The present application utilizes the high ion conductivity of the fast ion conductor to greatly reduce the resistance change voltage of the active metal electrode memristor, and the resistance state can be stably and slowly changed, thereby achieving a modulation effect on the on and off of the metal conductive filament, and improving the stability and consistency of the memristor; The resistance state of the memristor of the present application can be stably and slowly changed, and its conductance will not suddenly increase. The conductance of the memristor unit can change continuously with the external electric field, realizing the synaptic characteristic of continuously adjustable conductance and improving the synaptic linearity. It can be used as a basic synaptic unit in a neuromorphic computing system, which is beneficial to the preparation of high-storage capacity memory chips and the research and development of hardware for storage fusion computing and neuromorphic computing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the structure of the memristor unit of the present application; Figure 2 The DC characteristic diagram of the memristor unit obtained in the embodiment and the comparative example; Figure 3 100 DC cycle performance diagrams of the memristor units obtained in the embodiment and the comparative example; Figure 4 The DC characteristic diagrams of the memristor unit obtained in the embodiment and the comparative example under different current limiting voltages and different reset voltages; Figure 5 Schematic diagram of the fast ion conduction-oxide stacked memristor synaptic characteristics of the memristor unit obtained in Example 1. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. 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.

[0017] Memristor is a widely used microelectronic device. As the requirements for the consistency and synaptic linearity of memristor storage devices become increasingly higher, the on and off of most conductive filament memristors currently available are random, and there are problems such as discrete operating voltage and high and low resistance state distribution.

[0018] Based on this, this application was created.

[0019] The present application provides a fast ion conductor active electrode memristor functional layer material, comprising a stacked fast ion conductor layer and an amorphous oxide layer; the ionic conductivity of the fast ion conductor layer is greater than the ionic conductivity of the amorphous oxide layer, the resistivity of the amorphous oxide layer is much greater than the resistivity of the fast ion conductor layer, and the amorphous oxide layer contains an ion migration channel.

[0020] In the present application, the fast ion conductor layer has excellent ionic conductivity, which can effectively promote the directional migration of active metal cations to the amorphous oxide layer to form stable conductive filaments under low electric field strength, thereby significantly reducing the operating resistance change voltage of the memristor; the amorphous oxide layer has high resistivity and contains ion migration channels, ensuring that the active metal cations can efficiently migrate between different layers while maintaining the overall electrical insulation properties of the material. Therefore, the high ionic conductivity of the fast ion conductor can greatly reduce the resistance change voltage of the active metal electrode memristor, and the resistance state can be stably and slowly changed, achieving the modulation effect of the on-off of the metal conductive filament, and improving the stability and consistency of the memristor; in addition, the design of the stacked fast ion conductor layer and the amorphous oxide layer also improves the synaptic characteristics of the continuously adjustable conductivity, further enhancing the synaptic linearity of the memristor, making it highly potential to become the basic synaptic unit in the neuromorphic computing system.

[0021] In some embodiments, the chemical composition of the fast ion conductor layer includes a fast ion conductor material containing silver and / or copper ions, and the chemical composition of the amorphous oxide layer includes an amorphous metal oxide.

[0022] In some embodiments, the fast ion conductor material containing silver and / or copper ions is a sulfide containing silver and / or copper ions, including but not limited to Ag2Te x S 1-x , (0.3≤x≤0.7); the metal elements in the amorphous metal oxide include one or more of Hf, Al, Ti, Ta, Cu, W, Ni, Zn, Zr, Fe, Mn and Nb. It is worth noting that there are migration channels for silver or copper ions in the oxide layer under an external electric field; the metal oxide layer of the present application is an amorphous film, which greatly reduces the difficulty of film growth on the one hand, and solves the problems of uncontrollable formation sites of conductive filaments caused by uneven distribution of grain boundaries of polycrystalline materials and large performance differences between individual devices on the other hand.

[0023] like Figure 1 As shown, the present application provides a memristor unit including a fast ion conductor active electrode memristor functional layer material, including an inert electrode, an amorphous oxide layer, a fast ion conductor layer, and an active electrode stacked in sequence. The fast ion conductor layer is located between the active metal electrode and the amorphous oxide layer.

[0024] The memristor functional layer of the present application is placed between the inert electrode and the active electrode, and is in direct contact with both to form a sandwich structure. In some embodiments, the active electrode is mainly a silver electrode or a copper electrode, and its thickness is 20 to 200 nm, preferably 100 nm. In some embodiments, the inert electrode is preferably a material compatible with the CMOS process of integrated circuit chip technology such as TiN, TaN, or a precious metal such as Pt, Au, Pd, Ir, but not limited thereto. The electrode is prepared by a PVD process on the surface of the substrate, and its thickness is 20 to 200 nm, preferably 100 nm.

[0025] In the structure of the memristor unit, the fast ion conductor layer has a high ionic conductivity. Under the action of a low electric field, the active metal cations can undergo directional migration to form conductive filaments, greatly reducing the resistance-changing voltage of the active metal electrode memristor; and under the removal of the excitation, the active metal ions cannot migrate back due to the restrictions of the different active metal ion migration barriers of the fast ion conductor layer and the oxide layer, so that the functional layer material presents a non-volatile resistance state. At the same time, the addition of the oxide layer allows the resistance state to change steadily and slowly, achieving the modulation effect of the on-off of the metal conductive filaments, and improving the stability and consistency of the memristor. When the opposite external excitation is applied, the active metal ions overcome the migration barrier and retreat to the fast ion conductor layer, causing the electrical contact to be disconnected, that is, the active metal conductive filament is disconnected.

[0026] In some embodiments, the number of the fast ion conductor layer is ≥1, and the number of the amorphous oxide layer is ≥1.

[0027] In some embodiments, the thickness of the fast ion conductor layer is 5-200 nm, and the thickness of the amorphous oxide layer is 10-500 nm. The thickness of the metal oxide layer should not be too low or too high. If the thickness is too low, the metal conductive filament formed will suddenly break completely, resulting in a conductivity jump. If the thickness is too high, it will affect the on-off of the active metal conductive filament and cause the resistance voltage to increase.

[0028] The present application provides a method for preparing a memristor unit, comprising the following steps: Providing a substrate, and depositing an inert electrode on the surface of the substrate by using a physical vapor deposition process; Using magnetron sputtering technology, an amorphous oxide layer is pulse-deposited on the surface of the inert electrode; Depositing a fast ion conductor layer on the surface of the amorphous oxide layer by using a magnetron sputtering process; The active electrode pattern is prepared on the surface of the fast ion conductor layer by a photolithography process, and then the active electrode is deposited by a magnetron sputtering process. Specifically, the substrate is preferably a single crystal silicon substrate of SiO2, and the physical vapor deposition method is preferably magnetron sputtering. By magnetron sputtering, a layer of inert electrode is grown on a single-sided polished single crystal silicon substrate with SiO2, wherein the DC sputtering power is 30 to 200 W, preferably 70 W; the sputtering pressure is 0.2 to 2 Pa, preferably 0.6 Pa; the inert gas is Ar gas, the sputtering time is 600 s, and the sputtering thickness is preferably controlled to be 100 nm. The memristor oxide layer is prepared by pulse deposition on the prepared inert electrode by magnetron sputtering, the sputtering power and pressure are determined by the oxide layer material, the inert gas is Ar gas, and the sputtering thickness is preferably controlled to be 10 to 500 nm. The active metal layer is prepared by physical vapor deposition on the fast ion conductor layer, wherein the fast ion conductor layer is mainly a fast ion conductor material of silver and copper ions. Then, an active electrode pattern is prepared on the functional layer by a photolithography process, and an active electrode is grown by a magnetron sputtering method: first, an active electrode pattern is prepared on the functional layer by a photolithography process, wherein the photolithography steps include coating, pre-baking, pre-exposure, post-baking, post-exposure, and development; then, the active electrode material is sputtered onto the prepared functional layer by magnetron sputtering, and the sputtering pressure is 0.2 to 2 Pa, preferably 0.5 Pa; the inert gas is Ar gas, the sputtering time is 500 s, and the sputtering thickness is preferably controlled to be 100 nm; finally, the prepared active electrode film is soaked in acetone, assisted by ultrasonic cleaning, and then cleaned with anhydrous ethanol and deionized water in turn, and finally blown dry with a nitrogen gun to obtain the final memristor sample.

[0029] This application ensures the uniformity of device performance of materials in large-scale growth through amorphous oxide films grown by magnetron sputtering at room temperature, and utilizes the high ionic conductivity of fast ion conductors and the high resistance characteristics of oxides to effectively reduce the resistance-switching voltage of active metal electrode memristors, making the resistance-switching voltage and resistance distribution more concentrated, and ensuring the stable and slow change of the resistance state, thereby achieving precise modulation of the on-off of metal conductive filaments and improving the stability and consistency of memristors. In addition, the conductance of the memristor of the present invention can change continuously with the change of the external electric field, showing the characteristics of continuously adjustable conductance, which provides important support for realizing synaptic linearity in brain-like neuromorphic computing. This continuously adjustable conductivity characteristic has a significant promoting effect on the hardware implementation of storage fusion computing and neuromorphic computing.

[0030] The present application provides a modulation method of a memristor unit, comprising the following steps: S1. Applying a first external stimulus to the memristor unit causes metal cations in the fast ion conductor layer to migrate in the amorphous oxide layer to form conductive filaments; S2. withdrawing the first external excitation, so that the metal cations in step S1 are affected by the migration barrier and cannot migrate back to the fast ion conductor layer; S3. Apply a second external stimulus to migrate the metal cations in step S2 back to the fast ion conductor layer and disconnect the conductive filaments in the amorphous oxide layer.

[0031] The positive and negative poles of the first external excitation and the second external excitation are opposite.

[0032] The present application realizes the switching between high and low resistance states of the memristor unit by turning on and off the conductive filaments of the amorphous oxide layer.

[0033] Specifically, in the above-mentioned memristor unit, a specific external excitation / SET operation is applied to set logic 1, and when the opposite external excitation is applied, the / RESET operation is logic 0. By applying a certain logic circuit to the above-mentioned memristor unit, the on-off of the metal conductive wire can be controlled to realize the storage of logical series and data. The mechanism is that due to the different band gaps of the two materials and the different migration barriers of the active metal ions, in this heterostructure, a specific external excitation / SET operation is applied, and the active metal ions migrate, which can form active metal conductive filaments in the oxide layer; at the same time, the external excitation is withdrawn, and the active metal ions cannot migrate back to the original position due to the influence of the migration barrier, making the device non-volatile. When the opposite external excitation / RESET operation is applied, the active metal ions overcome the migration barrier and retreat to the fast ion conductor layer, so that the metal conductive filament in the oxide layer is disconnected. Thus, the switching between the high and low resistance states of the memristor can be realized by the on-off of the metal conductive filament in the oxide layer.

[0034] During the modulation process, the present application uses external excitation to induce the migration of active metal ions, thereby forming active metal conductive filaments to achieve the change of the overall resistance value of the memory device. The fast ion conductor layer and the oxide layer in the functional layer have different active metal ion migration barriers. Active metal ions with low barriers are easier to migrate, and active metal ions with high barriers require higher energy to migrate. Under external excitation conditions, the active metal ions in the fast ion conductor layer are more likely to migrate, while the active metal ions in the oxide layer are more difficult to migrate. Active metal conductive filaments are gradually formed in the oxide layer, and the resistance state can be stably changed slowly. Therefore, when external excitation is applied, the cycle consistency of the memristor of the present invention will be better. Because the migration barriers of the fast ion conductor layer and the oxide layer are different in height and the content of active metal ions is different, under the condition of external pulse excitation, the break of the active metal conductive filament is gradually disconnected, and the conductance jump caused by sudden complete breakage will not occur. Therefore, the memristor of the present invention has better synaptic weight slow change characteristics.

[0035] In a fifth aspect, the present application provides an application of a memristor unit in an artificial neural network chip.

[0036] The present solution is further described below through specific embodiments.

[0037] Example 1 A memristor cell (Ag / Ag2Te x S 1-x / HfO2 / W), from bottom to top, mainly includes substrate, inert electrode, oxide layer, fast ion conductor layer and active electrode. The specific steps are as follows: Substrate cleaning: First use acetone to clean in an ultrasonic environment for 10 minutes, then use alcohol to clean in an ultrasonic environment for 10 minutes, rinse with deionized water, and finally blow dry with a nitrogen gun; Magnetron sputtering W electrode: Using a W target, a 50 nm W bottom electrode was grown by sputtering for 300 s in an Ar gas atmosphere of 0.5 Pa at a DC sputtering power of 70 W.

[0038] Preparation of oxide layer and fast ion conductor layer: HfO2 and Ag2Te were prepared on the inert electrode by photolithography process respectively. x S 1-x Layer pattern, wherein the photolithography steps include coating, pre-baking, pre-exposure, post-baking, post-exposure, and development; HfO2 and Ag2Te are used respectively x S 1-x The target was sputtered at 60 W and 15 W in an Ar atmosphere of 0.6 Pa to grow a 75 nm HfO2 layer and a 60 nm Ag2Te x S 1-x layer (x=0.3); the prepared thin film samples were soaked in acetone, assisted by ultrasonic cleaning, and then washed with anhydrous ethanol and deionized water in turn, and finally dried with a nitrogen gun to obtain amorphous HfO2 and Ag2Te x S 1-x Functional layer.

[0039] Preparation of active electrode: Ag is selected as the active electrode, the active electrode pattern is prepared on the functional layer by photolithography, and the Ag electrode is grown by magnetron sputtering.

[0040] Photolithography: The active electrode pattern is prepared on the functional layer by photolithography process, wherein the photolithography steps include coating, pre-baking, pre-exposure, post-baking, post-exposure, and development; Sputtering: A metal Ag target was used in the experiment. A 100 nm Ag electrode was grown by sputtering for 500 s at a sputtering power of 20 W in an Ar atmosphere of 0.5 Pa. Stripping: Soak the prepared thin film sample in acetone, assist with ultrasonic cleaning, then clean it with anhydrous ethanol and deionized water in turn, and finally blow dry it with a nitrogen gun; the final superlattice memristor sample is obtained.

[0041] Comparative Example 1 A HfO2 memristor mainly includes a substrate, an inert electrode, a functional layer and an active electrode from bottom to top. The specific steps are as follows: Preparation of electrodes: W is selected as an inert electrode, and a layer of W electrode is grown on a single-sided polished single-crystalline silicon substrate with SiO2 grown thereon by magnetron sputtering.

[0042] Substrate cleaning: First use acetone to clean in an ultrasonic environment for 10 minutes, then use alcohol to clean in an ultrasonic environment for 10 minutes, rinse with deionized water, and finally blow dry with a nitrogen gun; Magnetron sputtering W electrode: Using a W target, a 50 nm W bottom electrode was grown by sputtering for 300 s in an Ar gas atmosphere of 0.5 Pa at a DC sputtering power of 70 W.

[0043] Preparation of oxide layer: Prepare HfO2 layer pattern on the inert electrode by photolithography process, wherein the photolithography steps include coating, pre-baking, pre-exposure, post-baking, post-exposure and development; use HfO2 target to sputter grow 75nm HfO2 layer in 0.6 Pa Ar atmosphere at a sputtering power of 60 W; soak the prepared thin film sample in acetone, assist with ultrasonic cleaning, and then clean with anhydrous ethanol and deionized water in turn, and finally blow dry with a nitrogen gun to obtain an amorphous HfO2 functional layer.

[0044] Preparation of active electrode: Ag is selected as the active electrode, the active electrode pattern is prepared on the functional layer by photolithography, and the Ag electrode is grown by magnetron sputtering.

[0045] Photolithography: The active electrode pattern is prepared on the functional layer by photolithography process, wherein the photolithography steps include coating, pre-baking, pre-exposure, post-baking, post-exposure, and development; Sputtering: A metal Ag target was used in the experiment. A 100 nm Ag electrode was grown by sputtering for 500 s at a sputtering power of 20 W in an Ar atmosphere of 0.5 Pa. Stripping: Soak the prepared thin film sample in acetone, assist with ultrasonic cleaning, then clean it with anhydrous ethanol and deionized water in turn, and finally blow dry it with a nitrogen gun; the final superlattice memristor sample is obtained.

[0046] Comparative Example 2 A kind of Ag2Te x S 1-x The memristor mainly includes substrate, inert electrode, functional layer and active electrode from bottom to top. The specific steps are as follows: Preparation of electrodes: W is selected as an inert electrode, and a layer of W electrode is grown on a single-sided polished single-crystalline silicon substrate with SiO2 grown thereon by magnetron sputtering.

[0047] Substrate cleaning: First use acetone to clean in an ultrasonic environment for 10 minutes, then use alcohol to clean in an ultrasonic environment for 10 minutes, rinse with deionized water, and finally blow dry with a nitrogen gun; Magnetron sputtering W electrode: Using a W target, a 50 nm W bottom electrode was grown by sputtering for 300 s in an Ar gas atmosphere of 0.5 Pa at a DC sputtering power of 70 W.

[0048] Preparation of fast ion conductor layer: Ag2Te is prepared on the inert electrode by photolithography x S 1-x Layer pattern, wherein the photolithography steps include coating, pre-baking, pre-exposure, post-baking, post-exposure, and development; using Ag2Te x S 1-x The target was sputtered at 15W sputtering power in 0.6 Pa Ar atmosphere to grow 60nm Ag2Te x S 1-x layer (x=0.3); the prepared film sample was soaked in acetone, assisted by ultrasonic cleaning, then cleaned with anhydrous ethanol and deionized water in turn, and finally dried with a nitrogen gun to obtain amorphous Ag2Te x S 1-x Functional layer.

[0049] Preparation of active electrode: Ag is selected as the active electrode, the active electrode pattern is prepared on the functional layer by photolithography, and the Ag electrode is grown by magnetron sputtering.

[0050] Photolithography: The active electrode pattern is prepared on the functional layer by photolithography process, wherein the photolithography steps include coating, pre-baking, pre-exposure, post-baking, post-exposure, and development; Sputtering: A metal Ag target was used in the experiment. A 100 nm Ag electrode was grown by sputtering for 500 s at a sputtering power of 20 W in an Ar atmosphere of 0.5 Pa. Stripping: Soak the prepared thin film sample in acetone, assist with ultrasonic cleaning, then clean it with anhydrous ethanol and deionized water in turn, and finally blow dry it with a nitrogen gun; the final superlattice memristor sample is obtained.

[0051] Test and Evaluation For the Ag / Ag2Te of Example 1 x S 1-x / HfO2 / W memristor is tested for electrical performance. The specific steps are as follows: Step a: Initialize the initial unit, ground its active electrode, apply a negative scanning voltage of 0 V to -2 V to the inert electrode, and set the limiting current to 10 mA, in order to first form a conductive path for the subsequent resistance change process; Step b: Apply multiple bidirectional DC I / V voltage scans to the cell initialized in step a. The voltage scan range is -1 V to 2 V. The limiting current is set to 10 mA. The DC characteristics are as follows: Figure 2 (a) shows that the cycle performance is Figure 3 As shown; Step c: Adjust the limiting current to 10 mA, 1 mA, 100 μA, 1 μA in turn, and measure the multi-value resistance state under different current limiting conditions, such as Figure 4 (a) shows that the voltage scanning range is adjusted to measure the multi-value resistance state under different scanning voltages, such as Figure 4 (b) The memristor of the first embodiment is subjected to a fixed pulse test. This test is a synaptic performance test of the memristor pulse neural network. The synaptic characteristics are as follows: Figure 5 shown.

[0052] The electrical performance test of the HfO2 memristor of comparative example 1 is carried out, and the specific steps are as follows: Step a: Initialize the initial unit, ground its active electrode, apply a negative scanning voltage of 0 V to -2 V to the second electrode, and set the limiting current to 10 mA. The purpose is to form a conductive path first, so that the subsequent resistance change process can proceed; Step b: Apply multiple bidirectional DC I / V voltage scans to the cell initialized in step a. The voltage scan range is -1 V to 2 V. The limiting current is set to 10 mA. The DC cycle characteristics are as follows: Figure 2 As shown in (b), compared with the embodiment, the device resistance switching voltage is significantly larger and the cycle performance is poor.

[0053] Comparative Example 2 Ag2Te x S 1-x The electrical performance test of the memristor is carried out in the following steps: Step a: Initialize the initial unit, ground its active electrode, apply a negative scanning voltage of 0 V to -2 V to the second electrode, and set the limiting current to 10 mA. The purpose is to form a conductive path first, so that the subsequent resistance change process can proceed; Step b: Apply multiple bidirectional DC I / V voltage scans to the cell initialized in step a. The voltage scan range is -1 V to 2 V. The limiting current is set to 10 mA. The DC cycle characteristics are as follows: Figure 2 As shown in (c), in comparison with the embodiment, the device resistance change is volatile, and the high resistance is relatively low, and the distinction between high and low resistance states is not obvious; The above test shows that the stacked structure of the oxide layer and the fast ion conductor layer in the present application can show good electrical performance. Figure 3 By comparing the DC characteristics of the embodiment and the comparative example, it can be shown that: Ag2Te x S 1-xCompared with HfO2 memristor, the Set and Reset process voltages of the Ag2Te2 memristor are smaller. By comparing the cycle performance of Example 1 with that of Comparative Examples 1 and 2, it can be shown that the double-layer stacked memristor has better consistency, and its consistency of 100 DC cycles is significantly better than the cycle performance of the HfO2 memristor, which fails in the second cycle. x S 1-x / HfO2 memristor can achieve slow resistance change and has the modulation effect of conducting filament on and off. Figure 4 By adjusting the limiting current and voltage range of the device, the resistance of the high and low resistance states of the device can be accurately controlled, and the intermediate resistance states are numerous and clear. x S 1-x / HfO2 superlattice memristor has better continuous adjustability of conductance than HfO2 memristor and has the potential to be applied in neuromorphic computing. Figure 5 According to the fixed pulse diagram of the embodiment, it can be seen that the superlattice memristor in the figure gradually changes from a high resistance state to a low resistance state under the pulse excitation of the same negative voltage; and changes from a low resistance state to a high resistance state under the pulse excitation of the same positive voltage. Under the negative pulse, as the number of pulses increases (increases with time), the conductance of the memristor gradually increases, and the change in conductance shows a continuously adjustable and nearly linear upward trend. It proves that the resistance value of the memristor has the characteristic of linear continuous adjustment, which meets the characteristic requirements of neural network calculation for synaptic devices.

[0054] The present invention effectively reduces the resistance change voltage of the active metal electrode memristor and ensures the stable and slow change of the resistance state, thereby realizing the precise modulation of the on and off of the metal conductive filament and improving the stability and consistency of the memristor. In addition, the conductance of the memristor of the present invention can change continuously with the change of the external electric field, showing the characteristic of continuously adjustable conductance, which provides important support for realizing the synaptic linearity in brain-like neuromorphic computing. This continuously adjustable conductivity characteristic has a significant promoting effect on the hardware implementation of storage fusion computing and neuromorphic computing. The stacked memristor device unit of the present invention and its preparation method provide a new solution for high-performance memristor devices by optimizing material selection and structural design, and are expected to be widely used in the fields of memory technology, neuromorphic computing, and artificial intelligence hardware.

[0055] The above are only preferred specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A fast ion conductor active electrode memristor functional layer material, characterized in that: It comprises a stacked fast ion conductor layer and an amorphous oxide layer; the ion conductivity of the fast ion conductor layer is greater than that of the amorphous oxide layer, the resistivity of the amorphous oxide layer is greater than that of the fast ion conductor layer, and the amorphous oxide layer contains an ion migration channel.

2. The fast ion conductor active electrode memristor functional layer material according to claim 1, characterized in that: The chemical composition of the fast ion conductor layer includes a fast ion conductor material containing silver and / or copper ions, and the chemical composition of the amorphous oxide layer includes an amorphous metal oxide.

3. The fast ion conductor active electrode memristor functional layer material according to claim 2, characterized in that: The fast ion conductor material containing silver and / or copper ions is a sulfide containing silver and / or copper ions, and the metal elements in the amorphous metal oxide include one or more of Hf, Al, Ti, Ta, Cu, W, Ni, Zn, Zr, Fe, Mn and Nb.

4. A memristor unit comprising the fast ion conductor active electrode memristor functional layer material according to any one of claims 1 to 3, characterized in that: It includes an inert electrode, an amorphous oxide layer, a fast ion conductor layer and an active electrode which are stacked in sequence.

5. The memristor unit according to claim 4, characterized in that: The number of the fast ion conductor layer is ≥1, and the number of the amorphous oxide layer is ≥1.

6. The memristor unit according to claim 4, characterized in that: The thickness of the fast ion conductor layer is 5-200 nm, and the thickness of the amorphous oxide layer is 10-500 nm.

7. A method for preparing a memristor unit according to any one of claims 4 to 6, characterized in that: The following steps are involved: Providing a substrate, and depositing an inert electrode on the surface of the substrate by a physical vapor deposition process; Depositing an amorphous oxide layer on the surface of the inert electrode by a magnetron sputtering process; Depositing a fast ion conductor layer on the surface of the amorphous oxide layer by using a magnetron sputtering process; An active electrode pattern is prepared on the surface of the fast ion conductor layer by a photolithography process, and then the active electrode is deposited by a magnetron sputtering process.

8. A modulation method for a memristor unit according to any one of claims 4 to 6, characterized in that: The following steps are involved: S1. applying a first external stimulus to the memristor unit to cause metal cations in the fast ion conductor layer to migrate in the amorphous oxide layer to form conductive filaments; S2. withdrawing the first external excitation, so that the metal cations in step S1 cannot migrate back to the fast ion conductor layer due to the migration barrier; S3. Applying a second external stimulus to migrate the metal cations in step S2 back to the fast ion conductor layer and disconnect the conductive filaments in the amorphous oxide layer.

9. The modulation method of the memristor unit according to claim 8, characterized in that: The first external excitation voltage and the second external excitation voltage have opposite positive and negative polarities.

10. Application of the memristor unit according to any one of claims 4 to 6 in an artificial neural network chip.

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