A memristor unit based on double-ion regulation and a preparation method thereof

Abstract

The application relates to a dual-ion regulation-based memristor unit and a preparation method thereof, adopts a simple plane memristor structure, has a simple process, and adopts an ion intercalation process to insert a first ion and a second ion into a Van der Waals gap of a dielectric layer, different resistance change phenomena are generated by changing the size and direction of an electric field applied on the memristor unit, and then the phenomena are consistent with the phenomenon that multiple ions in a biological synaptic plasticity change process jointly act, Ca 2+ and protein ion migration behaviors are simulated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of integrated microelectronic device technology and neuromorphic computing, and in particular, to a dual-ion regulated memristor unit and a preparation method thereof. BACKGROUND

[0002] With the development of information technology, the huge data throughput puts forward more stringent requirements on the computing power and computing speed of computers. The development of traditional CMOS devices based on the Von Neumann architecture has been challenged by a series of challenges such as high cost, high power consumption, high leakage current, and "memory wall".

[0003] A memristor is a basic circuit element used to represent the relationship between electric charge and magnetic flux. By changing the size of the electric field applied to the memristor, the functional ions in the device migrate and form a conductive path inside, changing the resistance from a high resistance state to a low resistance state, thereby realizing the switching from "0" to "1" and thus having the function of information storage. As a memory, the memristor has the advantages of low power consumption, small size, simple structure, high parallelism, easy three-dimensional stacking, non-volatility, etc., and has become a research hotspot in the field of microelectronic devices.

[0004] In addition, the memristor can also be used as a neuromorphic device to simulate the neurons and synapses of artificial neural networks. The currently developed memristors based on the migration of cations and anions, phase change, ferroelectric flip, and organic oxidation-reduction reaction are very similar in structure to the synapses in the human brain. Some studies have proposed to use the internal ion migration process of the memristor to simulate the process of Ca 2+ flow into the synapse after stimulation, but this research method can only simulate the migration behavior of a single ion in the synapse (in addition to Ca 2+ in the biological synapse, there are a large number of protein ions such as NMDA, protein phosphatase, and plasticity-related proteins), and cannot more vividly simulate the complex functions of the synapse. SUMMARY

[0005] The problem solved by the present application is how to simply construct a dual-ion regulated memristor unit to simulate the migration behavior of Ca 2+ and protein ions in the biological synapse.

[0006] To solve the above problems, the present application provides a dual-ion regulated memristor unit, which comprises a substrate, a first electrode and a second electrode spaced apart on the substrate, a dielectric layer interposed between the first electrode and the second electrode, the dielectric layer having a van der Waals gap, a first ion and a second ion interposed in the van der Waals gap of the dielectric layer, the first electrode being grounded, and the second electrode being connected to a voltage.

[0007] The beneficial effects of the present application are: a simple planar memristor structure is adopted, the process is simple, and by inserting two kinds of ions in the dielectric layer, the two kinds of ions have different migration forces under the driving of the same electric field, different resistance change phenomena are generated by changing the size and direction of the electric field applied on the memristor unit, and then the phenomenon of the common action of the multiple ions in the biological synaptic plasticity change process is matched, the Ca 2+ And the migration behavior of protein ions.

[0008] As preferred, the first electrode and the second electrode are both inert metal electrodes or metal oxides.

[0009] As preferred, the migration barrier of the first ion is greater than that of the second ion.

[0010] As preferred, the thickness of the first electrode and the second electrode is 2nm-60nm; and the thickness of the dielectric layer is 10nm-30nm.

[0011] A preparation method of a memristor based on double-ion regulation, comprising the following steps:

[0012] Step 1: preparing a dielectric layer on a substrate by a mechanical exfoliation method;

[0013] Step 2: depositing a first electrode and a second electrode on the dielectric layer by using ultraviolet lithography and electron beam evaporation;

[0014] Step 3: inserting a first ion and a second ion into the Van der Waals gap of the dielectric layer by using an ion intercalation process.

[0015] The beneficial effects of the present application are: by using the ion intercalation process, the first ion and the second ion are inserted into the Van der Waals gap of the dielectric layer, and at the same time, the interlayer spacing of the step layer can be expanded, by applying different sizes and directions of electric field on the first electrode and the second electrode, the migration force of the first ion and / or the second ion is regulated, different resistance change phenomena are generated, and the synaptic function of complex organisms is simulated.

[0016] As preferred, the ion intercalation process in step 3 specifically comprises:

[0017] Step 301: mixing an organic alkali metal solution containing the first ion and an organic alkali metal solution containing the second ion in a proportion in an inert atmosphere;

[0018] Step 302: immersing the prepared memristor unit into the mixed solution for 15min-120min. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of embodiment 1 of the present application;

[0020] Figure 2 Current-voltage characteristic curve for the resistance change effect test in embodiment 2 of the present application;

[0021] Figure 3 Turn-on voltage curve for the ion-doped memristor unit in embodiment 2 of the present application;

[0022] Figure 4 Short-range synapse plasticity test in embodiment 2 of the present application;

[0023] Figure 5 Long-range synapse plasticity test in embodiment 2 of the present application;

[0024] Figure 6 Current-voltage characteristic curve for the resistance change effect test in embodiment 2 of the present application with soaking time less than 15 min;

[0025] Figure 7 Current-voltage characteristic curve for the resistance change effect test in embodiment 2 of the present application with soaking time more than 120 min.

[0026] BRIEF DESCRIPTION OF DRAWINGS

[0027] 1, substrate; 2, second electrode; 3, second ion; 4, dielectric layer; 5, first ion; 6, first electrode. DETAILED DESCRIPTION

[0028] In order to make the above objectives, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings.

[0029] It will be understood that, although the terms “first”, “second”, etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0030] Based on the fact that the memristor in the prior art can only simulate the migration behavior of a single ion in a synapse, it is unable to more vividly simulate the complex functions of the synapse. Therefore, the present application provides a memristor unit capable of simulating the complex synapse functions of living organisms. EMBODIMENT 1

[0032] Specific reference Figure 1The application provides a memristor unit based on double-ion regulation, which comprises a substrate 1, a first electrode 6 and a second electrode 2 which are arranged at intervals on the substrate 1, and a dielectric layer 4 which is inserted between the first electrode 6 and the second electrode 2. The dielectric layer 4 in the embodiment is a layered inorganic two-dimensional material, the dielectric layer 4 has a plurality of unit intervals, the unit intervals are connected by Van der Waals force, the dielectric layer 4 has a Van der Waals gap, the first ion 5 and the second ion 3 are inserted into the Van der Waals gap of the dielectric layer 4, the first electrode 6 and the second electrode 2 are inert metal electrodes or metal oxides, and the inert metal electrodes or metal oxides include but are not limited to one or two of Au, Pt, Cr, Ti, W and ITO, the migration barrier of the first ion 5 is greater than that of the second ion 3, the thickness of the first electrode 6 and the second electrode 2 in the embodiment is 40 nm, and the thickness of the dielectric layer 4 is 20 nm. The first electrode 6 is grounded, and the second electrode 2 is connected to a voltage. Embodiment 2

[0034] A preparation method of a memristor based on double-ion regulation, which comprises the following steps:

[0035] Step 1: preparing the dielectric layer 4 on the substrate 1 by a mechanical exfoliation method; the dielectric layer 4 in the embodiment is a MoS2 film with a thickness of 20 nm; the mechanical exfoliation method for preparing the dielectric layer 4 specifically comprises the following steps: a layer of MoS2 film with a preset size is exfoliated from a MoS2 bulk body by using a thermal release tape, another clean thermal release tape is used to adhere to the MoS2 film, the two tapes are tightly adhered and then exfoliated again, and the MoS2 film with a thickness of 20 nm is obtained after multiple exfoliations; then the thermal release tape is adhered to SiO2 or Si, and heat release is performed at a temperature of 120 DEG C after adhesion; finally, the dielectric layer 4 is cleaned by using a plasma cleaner with pure Ar gas;

[0036] Step 2: depositing the first electrode 6 and the second electrode 2 on the dielectric layer 4 by using ultraviolet lithography and electron beam evaporation; specifically, the following operations are sequentially performed on the substrate 1 with the MoS2 film: gluing, drying, exposure, development, fixation and film hardening, which are prior art and will not be described in detail here; then, the electrode is patterned by using a contact type ultraviolet lithography machine; then, a 5-nm Ti electrode is evaporated by using an electron beam evaporation instrument, a 40-nm Au electrode is evaporated, and finally, the excess photoresist is removed by using a photoresist remover;

[0037] Step 3: inserting the first ion 5 and the second ion 3 into the Van der Waals gap of the dielectric layer 4 by using an ion intercalation process; the ion intercalation process specifically comprises the following steps:

[0038] Step 301, mixing the organic alkali metal solution containing the first ion 5 and the organic alkali metal solution containing the second ion 3 in a proportion in an inert atmosphere; the first ion 5 in the embodiment is Mg2+, and the second ion 3 is Li+, and the n-butyllithium and dibutyl magnesium solution with a concentration ratio of 1:1 are mixed in a high-purity Ar glove box;

[0039] Step 302, then immersing the prepared memristor unit into the mixed solution, and the first ion 5 and the second ion 3 spontaneously diffuse into the Van der Waals gap of the medium layer 4, and the immersion time is 15 min-120 min, and the n-hexane is used for flushing to wash away the excess solution on the surface of the memristor unit;

[0040] The memristor unit of the embodiment is obtained through the above steps.

[0041] In addition, the material of the medium layer 4 in the embodiment includes but is not limited to a MoS2 film, such as a MoSe2 film or a MoTe2 film; but the preparation method of the medium layer 4 is the same;

[0042] In addition, in the embodiment, the immersion time of the memristor immersed in the mixed solution is tested by current-voltage, the scanning voltage is from 0 to 6V, then from 6V to-6V, and finally from-6V to 0, and the current-voltage curve as shown in the figure is obtained. Figure 6 When the immersion time of the memristor is less than 15 min, the amount of functional ion insertion is too small to produce obvious resistance change effect; however, when the immersion time of the memristor is more than 120 min, the semiconductor phase MoS2 of the memristor is completely changed into a metal phase, a metal conduction phenomenon is produced, and the resistance switching phenomenon cannot be obtained. Figure 7

[0043] The preparation method of the first electrode 6 and the second electrode 2 in the embodiment includes but is not limited to ultraviolet lithography and electron beam evaporation, such as magnetron sputtering, physical atomic layer deposition, thermal evaporation and the like;

[0044] The electrode patterning method of the first electrode 6 and the second electrode 2 in the embodiment includes but is not limited to ultraviolet lithography, such as electron beam exposure, laser direct writing, ultraviolet exposure and the like;

[0045] The first ion 5 and the second ion 3 in the embodiment are alkali metal ions of the organic alkali metal solution, including but not limited to one or two of n-butyllithium, dibutyl magnesium, triisobutylaluminum and n-butyllithium;

[0046] The inert atmosphere in the embodiment is an Ar atmosphere, including but not limited to Ar or N2;

[0047] ​In this specific embodiment, substrate 1 includes, but is not limited to, one or two of SiO2 / Si substrate 1, sapphire substrate 1, and Si substrate 1.

[0048] In addition, the memristor unit of the specific embodiment was tested, specifically using a Keithley 4200 semiconductor parameter measuring instrument to perform the following tests on the memristor unit:

[0049] (1) Resistance effect test

[0050] A resistive switching effect test was performed on the memristor unit of a specific embodiment. The first electrode 6 was grounded, and a scanning voltage was applied to the second electrode 2. The step voltage was set to 0.05V. The scanning voltage started from 0V and swept to 8V, then from 8V to -8V, and finally from -8V back to 0V, obtaining the following results: Figure 2 The current and voltage curves shown are from... Figure 2 As can be seen from the diagram, the memristor cell undergoes a memristor turn-on process under a negative voltage and a memristor reset process under a positive voltage. Furthermore, the memristor turn-on process is divided into two segments: the first segment occurs at -1V, representing the turn-on voltage of Li+, and the second segment occurs at -2V, representing the turn-on voltage of Mg2+.

[0051] (2) Ion doping tests at different concentration ratios

[0052] like Figure 3 As shown, ion intercalation was performed using n-butyllithium and dibutylmagnesium solutions with different molar concentrations. Then, the resistive switching effect of the prepared memristor unit was tested. The higher the concentration of Li+, the lower the overall turn-on voltage of the device, while the higher the concentration of Mg2+, the higher the turn-on voltage of the memristor. The turn-on voltage of the memristor unit can be controlled by adjusting the concentrations of the two ions.

[0053] (3) Synaptic plasticity test

[0054] like Figure 4 As shown, the prepared memristor unit was subjected to a synaptic short-term plasticity test. The first electrode 6 was grounded, and a pulse voltage was applied to the second electrode 2. The pulse width was 50ms, the reading voltage was 0.2V, and the pulse amplitude was 1V. After the voltage was applied, the corresponding current decreased to the initial value, which is similar to the short-term plasticity of biological synapses after stimulation.

[0055] like Figure 5 As shown, the prepared memristor unit was subjected to a synaptic long-term plasticity test. The first electrode 6 was grounded, and a pulse voltage was applied to the second electrode 2. The pulse width was 50ms, the reading voltage was 0.2V, and the pulse amplitude was 2V. After the voltage was applied, the corresponding current required a long time to decay before returning to the initial value, which is similar to the long-term plasticity of biological synapses after being stimulated.

[0056] The dual-ion regulation memristor unit prepared in the embodiment has the advantages of simple structure, simple operation, multiple regulation dimensions, and simulation of long-range and short-range plasticity of synapses, and provides a new idea for simulating biological neural morphological functions.

[0057] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited to this. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of the present disclosure.

Claims

1. A memristor unit based on dual-ion modulation, characterized in that, The device includes a substrate (1) and a first electrode (6) and a second electrode (2) spaced apart on the substrate (1). A dielectric layer (4) is inserted between the first electrode (6) and the second electrode (2). The dielectric layer (4) has a van der Waals gap, in which a first ion (5) and a second ion (3) are inserted. The first electrode (6) is grounded, and the second electrode (2) is connected to a voltage. The migration barrier of the first ion (5) is greater than that of the second ion (3). The first ion (5) is Mg. 2+ The second ion (3) is Li + The material of the dielectric layer (4) is MoS2, MoSe2, or MoTe2.

2. The memristor unit based on dual-ion modulation according to claim 1, characterized in that, The first electrode (6) and the second electrode (2) are both inert metal electrodes or metal oxides.

3. A memristor unit based on dual-ion modulation according to claim 1, characterized in that, The thickness of the first electrode (6) and the second electrode (2) is 2nm-60nm; the thickness of the dielectric layer (4) is 10nm-30nm.

4. A method for fabricating a memristor based on dual-ion modulation, based on the memristor unit based on dual-ion modulation according to any one of claims 1-3, characterized in that, Includes the following steps: Step 1: Prepare a dielectric layer (4) on the substrate (1) by mechanical peeling; Step 2: Deposit the first electrode (6) and the second electrode (2) on the dielectric layer (4) using ultraviolet lithography and electron beam evaporation; Step 3: Insert the first ion (5) and the second ion (3) into the van der Waals gap of the dielectric layer (4) using an ion intercalation process.

5. The method for fabricating a memristor based on dual-ion regulation according to claim 4, characterized in that, The ion intercalation process in step 3 specifically includes: Step 301: Mix the organic alkali metal solution containing the first ion (5) and the organic alkali metal solution containing the second ion (3) in an inert atmosphere in a certain proportion; Step 302: Immerse the prepared memristor unit in the mixed solution for 15-120 minutes.

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