Memristor based on molybdenum-doped vanadium dioxide phase change thin film material and preparation method thereof

Abstract

The present application relates to a kind of molybdenum-doped vanadium dioxide phase change film material-based memristor and its preparation method, by co-sputtering on Si base substrate to prepare amorphous molybdenum-doped vanadium dioxide phase change film material, and in the high-purity argon atmosphere of 400~450 ℃ Annealing 30~60 minutes, obtain high-quality MoxV1-xO2 Film.The present application also provides a kind of molybdenum-doped vanadium dioxide phase change film-based memristor preparation method, structure includes substrate layer, functional layer and top electrode layer.The prepared molybdenum-doped vanadium dioxide film shows excellent thermal stability, relatively wide thermal hysteresis interval and relatively low phase transition temperature.By MoxV1-xO2 Material as the functional layer of memristor, device has small size, low opening voltage and high room temperature stability and the like advantages.

Description

Technical Field

[0001] This invention relates to the technical field of phase change thin films and memristor fabrication. Specifically, it uses MoxV1-xO2 thin film material as the main functional layer of a memristor and improves the stability of the memristor by optimizing the electrode structure and size of the phase change switch. Background Technology

[0002] Driven by the current development of information technology and intelligentization, traditional storage technologies are gradually approaching their physical limits and cannot meet the demands for higher storage density and energy efficiency. Memristors, as a novel type of memory, have become a research hotspot due to their simple structure, low power consumption, and in-memory computing advantages, providing crucial support for artificial intelligence hardware and neuromorphic computing. Memristors can achieve data storage by adjusting their resistance and possess synaptic-like characteristics.

[0003] VO2 has become an ideal candidate for memristor materials due to its unique insulator-metal phase transition properties. VO2 undergoes a phase transition at specific threshold voltages or temperatures, resulting in a significant change in resistance and demonstrating its potential for memristor construction. However, practical applications of VO2 face challenges such as poor stability and high phase transition temperatures, which are particularly evident in low-power devices. Therefore, doping techniques have become an important means to improve the performance of VO2 and optimize its behavior in memristors. Summary of the Invention

[0004] The purpose of this invention is to provide a memristor based on Mo-doped vanadium dioxide phase change thin film material to improve switching stability and reduce power consumption.

[0005] The technical solution for achieving the first objective of this invention is:

[0006] A method for preparing a Mo-doped vanadium dioxide phase change thin film material includes the following specific steps:

[0007] Step 1: Pretreatment of Si substrate material; including cleaning and drying. During cleaning, ultrasonic cleaning is performed for 5-15 minutes with ethanol, acetone and deionized water respectively, and finally dried with high-purity nitrogen.

[0008] Step 2: Magnetron Sputtering Preparation: Using 99.99% pure V and Mo metal targets, respectively mounted on DC sputtering targets, the Si substrate material is fixed on the sample tray. The high-vacuum magnetron sputtering system chamber is evacuated, and high-purity argon and oxygen are used as sputtering gases; the magnetron sputtering chamber is evacuated to ≤5×10-5 Pa, the volume percentage of high-purity argon is ≥99.999%, and the volume percentage of high-purity oxygen is ≤1%.

[0009] Step 3: Magnetron sputtering of MoxV1-xO2 thin film material:

[0010] Step 3.1: Open the baffles of the metal V target and Mo target, and introduce high-purity argon and oxygen; turn on the DC power supply and pre-sputter for 1-5 minutes;

[0011] Step 3.2: Using the co-sputtering deposition method, set the sputtering power of V target and Mo target; open the sample baffle for sputtering; after sputtering is completed, turn off the sample baffle, DC power supply and target baffle to obtain an amorphous MoxV1-xO2 (0<x<1) phase change film;

[0012] Step 4: Heat treatment of MoxV1-xO2 thin film: The amorphous thin film is placed in a tube furnace for annealing; the molybdenum-doped vanadium dioxide phase change thin film material MoxV1-xO2 is obtained; its thickness is 90-180 nm; its roughness is <5 nm; wherein, the heat treatment is carried out in a high-purity argon atmosphere; the argon flow rate is 60-100 sccm, the temperature is 400-450 ℃, the holding time is 30-60 min, and then cooled to room temperature.

[0013] Clean the tubing before heat treatment to prevent sample oxidation; first evacuate the tubular furnace, then replace it with a large amount of argon gas, repeating 2 to 3 times; the heating rate of the heat treatment is 5 to 10 °C / min, and the cooling process is carried out with the furnace to room temperature.

[0014] The technical solution to achieve the second objective of this invention is:

[0015] A memristor based on molybdenum-doped vanadium dioxide phase change thin film material, the memristor comprising, from bottom to top: a Si substrate, a cross-shaped mark layer, a MoxV1-xO2 phase change thin film material layer, and a top electrode layer; its fabrication steps include:

[0016] Step 1: Pretreatment of Si-based substrate material;

[0017] Step 2: Preparation of the mark layer: Select a high-resistivity single crystal Si with a surface thickness of 90-300 nm as the substrate. After cleaning, drying and spin-coating the substrate with photoresist, use electron beam lithography to pattern the cross-shaped mark layer on the substrate. Then, deposit a 2-10 nm thick Cr and a 40-100 nm thick Au by magnetron sputtering. Use acetone solution to remove excess material and obtain the mark layer.

[0018] Step 3: Preparation of MoxV1-xO2 thin film material layer: Photoresist is spin-coated on the mark layer, and the phase change material layer is patterned by electron beam lithography according to the cross mark alignment. A MoxV1-xO2 thin film material with a thickness of 90-180 nm is deposited by magnetron sputtering. Excess material is removed by acetone solution to remove the photoresist, and the MoxV1-xO2 thin film material layer is obtained and then subjected to heat treatment.

[0019] Step 4: Fabrication of the top electrode layer: Spin-coat photoresist onto the MoxV1-xO2 thin film material layer, align and pattern the top electrode layer using electron beam lithography according to the cross markings, deposit 2-10 nm thick Cr and 40-100 nm thick Au by magnetron sputtering, remove excess material by acetone solution to obtain the top electrode layer, and fabricate the memristor based on the molybdenum-doped vanadium dioxide phase change thin film material.

[0020] In step 1, the pretreatment of the Si substrate material includes cleaning and drying. The cleaning process involves ultrasonically cleaning the Si substrate material in an ethanol solution for 5-15 minutes, then ultrasonically cleaning it in an acetone solution for 5-15 minutes, and finally ultrasonically cleaning it with deionized water for 5-15 minutes. After ultrasonic cleaning, the substrate material is dried with high-purity nitrogen.

[0021] In step 3, the heat treatment of the MoxV1-xO2 phase change thin film material layer is carried out in a high-purity argon atmosphere with an argon flow rate of 80-100 sccm, held at 400-450 ℃ for 30-60 min, with a heating rate of 5-10 ℃ / min, and finally cooled to room temperature in the furnace.

[0022] The memristor made of Mo-doped VO2 phase change thin film material is characterized in that the overall structural size of the device is ≤5×10 μm; and the channel width between the top electrodes is 0.6~2.0 μm.

[0023] This invention significantly reduces the phase transition temperature of VO2 and improves its conductivity through Mo doping, making it more suitable for switching applications in low-power memristors. Mo doping not only enhances the controllability and stability of the phase transition in the VO2 thin film but also effectively reduces the operating power consumption of the device.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] The memristor of this invention uses MoxV1-xO2 phase change thin film material as the main switching functional layer, exhibiting a low phase change temperature and a wide thermal hysteresis range. This invention employs a top electrode structure, which is simpler and easier to integrate. By reducing the electrode channel width and device size, heating efficiency is further improved, thereby reducing power consumption. This invention can improve the stability and integration of memristors, reduce power consumption, and provide an innovative approach for the development of novel high-speed memristor arrays. Attached Figure Description

[0026] Figure 1 This is a graph showing the relationship between resistance and temperature for the MoxV1-xO2 phase change thin film material and the VO2 phase change thin film material of this invention.

[0027] Figure 2This is a schematic diagram of the memristor structure based on MoxV1-xO2 phase change thin film material according to the present invention;

[0028] Figure 3 This is a schematic diagram of the fabrication method of the memristor based on MoxV1-xO2 phase change thin film material according to the present invention;

[0029] Figure 4 This is a test diagram of the room temperature threshold switching characteristics of the memristor based on the MoxV1-xO2 phase change thin film material of this invention. Detailed Implementation

[0030] In the following description, specific details such as particular system structures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known structures, materials, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0031] To illustrate the technical solution described in this invention, specific embodiments are described below. Example

[0032] A method for preparing Mo-doped vanadium dioxide phase change thin film material.

[0033] The preparation process of Mo-doped VO2 phase change thin film material is as follows: Amorphous MoxV1-xO2 thin films are deposited on Si substrates by co-sputtering with a 99.99% pure metal V target and a Mo target. The total thickness of the thin film material is 90–180 nm.

[0034] The Mo-doped vanadium dioxide phase change thin film material in this embodiment was prepared by magnetron sputtering. The specific preparation method includes the following steps:

[0035] (1) Pretreatment of Si substrate material: The Si substrate material was first ultrasonically cleaned in ethanol solution for 15 minutes, then ultrasonically cleaned in acetone solution for 15 minutes, and finally ultrasonically cleaned with deionized water for 10 minutes. After ultrasonic cleaning, it was dried with high-purity nitrogen.

[0036] (2) Magnetron sputtering preparation: The V target and Mo target are respectively installed on the DC sputtering target, the Si substrate is fixed on the sample tray, and the high vacuum magnetron sputtering system chamber is evacuated to 5×10-5 Pa. The volume ratio of argon to oxygen in the sputtering atmosphere is 100:1, the argon flow rate is 100 sccm, the oxygen flow rate is 1 sccm, and the vacuum degree of the magnetron sputtering chamber is 0.6 Pa during sputtering.

[0037] (3) Magnetron sputtering of MoxV1-xO2 phase change thin film material: Open the V target and Mo target baffles, turn on the DC power supply, set the sputtering power to 60 W and 1 W respectively, pre-sputter for 3 min, and formally sputter for 20 min to obtain an amorphous Mo0.014V0.986O2 phase change thin film with a thickness of 100 nm. After sputtering, turn off the sample baffle, DC power supply and target baffle;

[0038] (4) Heat treatment of Mo0.014V0.986O2 phase change thin film: The obtained amorphous thin film was placed in a tube furnace and annealed at 450℃ for 60 min with an argon flow rate of 80 sccm and a heating rate of 10 ℃ / min. Then it was naturally cooled to room temperature.

[0039] Comparative Example 1

[0040] The preparation process of a high-quality vanadium dioxide thin film is as follows:

[0041] (1) Pretreatment of Si-based substrate material: The cleaning steps are the same as in Example 1;

[0042] (2) Magnetron sputtering preparation: A metal V target with a purity of 99.99% was installed on a DC sputtering target. The Si substrate material was fixed on the sample tray. The vacuum degree of the sputtering chamber was 5×10-5 Pa. The volume ratio of argon to oxygen in the sputtering atmosphere was 100:1. The argon flow rate was 100 sccm and the oxygen flow rate was 1 sccm. The vacuum degree of the magnetron sputtering chamber was 0.6 Pa during the sputtering process.

[0043] (3) Magnetron sputtering of VO2 phase change thin film material: Open the V target baffle, set the DC power supply sputtering power to 60 W, pre-sputter for 3 min, and formally sputter for 20 min to obtain an amorphous VO2 phase change thin film with a thickness of 100 nm.

[0044] (4) Heat treatment of VO2 phase change thin film: The obtained amorphous thin film was placed in a tube furnace and annealed at 450 °C for 60 min with an argon flow rate of 80 sccm and a heating rate of 10 °C / min. The film was then cooled to room temperature.

[0045] Related performance tests

[0046] The resistance versus temperature relationship was tested on the MoxV1-xO2 phase change thin film material prepared in Example 1 and the VO2 phase change thin film material prepared in Comparative Example 1. The results are as follows: Figure 1 As shown, the heating rate during the test was 5 ℃ / min. The test results indicate that the phase transition temperature of the VO2 phase change thin film material is 69.7 ℃, while that of the MoxV1-xO2 phase change thin film material is 49 ℃. Example

[0047] A memristor based on Mo-doped vanadium dioxide phase change thin film material, such as Figure 2 As shown, from bottom to top, it includes: Si substrate, Mark layer, MoxV1-xO2 phase change thin film material layer and top electrode layer.

[0048] The memristor based on Mo-doped vanadium dioxide phase change thin film material in this embodiment is fabricated as follows: Figure 3 As shown, the specific preparation method includes the following steps:

[0049] (a) Pretreatment of Si-based substrate material: Same as in Example 1;

[0050] (b) Preparation of mark layer: A high-resistivity single crystal Si with a surface thickness of 300 nm SiO2 was selected as the substrate. After cleaning, drying and spin-coating the substrate with photoresist, the cross-shaped mark layer was patterned by electron beam lithography. Then, a 10 nm thick Cr and a 40 nm thick Au were deposited by magnetron sputtering. The excess material was removed by soaking in acetone solution to remove the photoresist and obtain the mark layer.

[0051] (c) Preparation of MoxV1-xO2 phase change thin film material layer: Photoresist was spin-coated on the mark layer, and the phase change material layer was patterned by electron beam lithography according to the cross mark alignment. Following the preparation method in Example 1, a 100 nm thick Mo0.014V0.986O2 thin film material was deposited by magnetron sputtering. The excess material was removed by immersion in acetone solution to remove the photoresist and obtain the phase change material layer; then it was heat-treated.

[0052] (d) Preparation of the top electrode layer: Photoresist was spin-coated onto the Mo0.014V0.986O2 phase change thin film material layer. The top electrode layer was patterned by electron beam lithography according to the cross mark alignment. A 10 nm thick Cr and a 40 nm thick Au were deposited by magnetron sputtering. The excess material was removed by soaking in acetone solution to remove the photoresist and obtain the top electrode layer. The channel width between the electrodes was 1.5 μm.

[0053] Figure 4 The results of the threshold switching characteristics test of the memristor based on the Mo0.014V0.986O2 phase change thin film material of the present invention are presented.

[0054] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the above embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for preparing a molybdenum-doped vanadium dioxide phase change thin film material, characterized in that, The method includes the following specific steps: Step 1: Pretreatment of Si-based substrate material; including cleaning and drying. During cleaning, ultrasonic cleaning is performed for 5-15 minutes with ethanol, acetone and deionized water respectively, and finally drying is performed with high-purity nitrogen gas. Step 2: Magnetron Sputtering Preparation: Using 99.99% pure V and Mo metal targets, respectively mounted on DC sputtering targets, the Si substrate material is fixed on the sample tray. The high-vacuum magnetron sputtering system chamber is evacuated, using high-purity argon and oxygen as sputtering gases; the magnetron sputtering chamber is evacuated to ≤5×10⁻⁶. -5 Pa, the volume percentage of high-purity argon is ≥99.999%, and the volume percentage of high-purity oxygen is ≤1%; Step 3: Magnetron sputtering of Mo x V 1-x O2 thin film materials: Step 3.1: Open the baffles of the metal V target and Mo target, and introduce high-purity argon and oxygen; turn on the DC power supply and pre-sputter for 1-5 minutes; Step 3.2: Using the co-sputtering deposition method, set the sputtering power of the V target and the Mo target; open the sample baffle for sputtering; after sputtering is complete, turn off the sample baffle, DC power supply and target baffle to obtain amorphous Mo. x V 1-x O2 phase change thin film, where 0 < x < 1; Step 4: Mo x V 1-x O2 thin film heat treatment: The amorphous thin film is placed in a tube furnace for annealing; the molybdenum-doped vanadium dioxide phase change thin film material Mo is obtained. x V 1-x O2; its thickness is 90–180 nm; roughness < 5 nm; wherein, the heat treatment is carried out entirely in a high-purity argon atmosphere; argon flow rate is 60–100 sccm, temperature is 400–450 ℃, holding time is 30–60 min, and then cooled to room temperature; wherein: The heat treatment described in step 4 involves cleaning the tubing before heat treatment to prevent sample oxidation; first, the tubular furnace is evacuated, and then replaced with a large amount of argon gas, repeated 2 to 3 times; the heating rate of the heat treatment is 5 to 10 °C / min, and the cooling process is carried out with the furnace to room temperature.

2. A memristor based on molybdenum-doped vanadium dioxide phase change thin film material, characterized in that, The memristor, from bottom to top, comprises: a Si substrate, a cross-shaped mark layer, and a Mo layer. x V 1-x O2 phase change thin film material layer and top electrode layer; the Mo x V 1-x The O2 phase change thin film material is prepared according to the method described in claim 1, and its memristor preparation steps include: Step 1: Pretreatment of Si-based substrate material; Step 2: Preparation of the mark layer: Select a high-resistivity single crystal Si with a surface thickness of 90-300 nm as the substrate. After cleaning, drying and spin-coating the substrate with photoresist, use electron beam lithography to pattern the cross-shaped mark layer on the substrate. Then, deposit a 2-10 nm thick Cr and a 40-100 nm thick Au by magnetron sputtering. Use acetone solution to remove excess material and obtain the mark layer. Step 3: Preparation of Mo x V 1-x O2 thin film material layer: Photoresist is spin-coated onto the mark layer, and the phase transition material layer is patterned by electron beam lithography according to the cross marks. A 90–180 nm thick Mo layer is deposited by magnetron sputtering. x V 1-x O2 thin film material was cleaned with acetone solution to remove excess material, yielding Mo. x V 1-x O2 thin film material layer, and then heat-treated; Step 4: Fabrication of the top electrode layer: In Mo x V 1-x Photoresist is spin-coated onto an O2 thin film material layer. The top electrode layer is patterned by electron beam lithography according to the cross mark alignment. A 2-10 nm thick Cr and a 40-100 nm thick Au are deposited by magnetron sputtering. Excess material is removed by acetone solution to remove the photoresist and obtain the top electrode layer, thus fabricating the memristor based on the molybdenum-doped vanadium dioxide phase change thin film material.

3. The memristor according to claim 2, characterized in that, The overall structural dimensions of the memristor are ≤5×10 μm; the channel width between the top electrodes is 0.6~2 μm.

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