Preparation method of flexible HZO ferroelectric memristor based on all-solution method

Abstract

The invention provides a preparation method of a flexible HZO ferroelectric memristor based on an all-solution method. The preparation method comprises the steps that S1, a mica sheet is used as a flexible substrate layer after being cleaned; s2, mixing a graphene conductive coating and ethanol according to a mass ratio of 1: 1000, stirring, carrying out ultrasonic treatment, layering graphene to obtain a mixture, uniformly dispensing the obtained mixture on the upper surface of the flexible substrate layer prepared in the S1, and heating and curing to prepare a bottom electrode layer; s3, mixing and stirring HfCl4 powder, ZrCl4 powder, an ethanol solution and deionized water according to a weight ratio of 1: 1: 10: 5, and performing ultrasonic treatment to obtain an HZO precursor solution; spin-coating the HZO precursor solution on the upper surface of the bottom electrode layer, and performing high-temperature annealing to form a nerve bionic layer; and S4, uniformly coating Pt conductive slurry on the upper surface of the nerve bionic layer prepared in the S3, and heating and curing to form the top electrode. The method effectively overcomes the problems of film forming difficulty and ferroelectric crystal structure regulation and control in the prior art, and has the advantages of simplicity, convenience and low cost.

Description

Technical Field

[0001] The present invention relates to the technical fields of non - volatile memories and flexible electronic devices, and particularly relates to a structural design and preparation method of a flexible HZO ferroelectric memristor prepared by a full - solution method. Background Art

[0002] With the increasing demand of modern electronic products for efficient, low - power - consumption, and high - performance non - volatile memories, ferroelectric memristors, as a new type of storage element, have become a research hotspot due to their excellent non - volatility, multi - state storage ability, excellent durability, and high - speed switching, and show broad application prospects in the fields of non - volatile storage, neural network computing, tactile and visual bionics, and wearable electronic devices. The working principle of ferroelectric memristors is based on the spontaneous polarization characteristics of ferroelectric materials. When an external electric field is applied, the polarization state of the ferroelectric material changes, thereby causing a controllable change in its resistance. This property enables ferroelectric memristors to simulate the behavior of biological neural synapses in neuromorphic computing, playing the role of information storage and transmission, and thus achieving efficient computing and data storage.

[0003] However, traditional perovskite ferroelectric materials (such as Pb(Zr,Ti)O3 and BiFeO3) are volatile at high temperatures, leading to potential environmental pollution, and their small bandgaps limit their applications in harsh environments such as high temperatures and high electric fields. In recent years, ferroelectric materials based on Zr:HfO2 (HZO) have become ideal choices for flexible wearable devices and bionic synaptic devices due to their lead - free, non - toxic characteristics, large bandgaps (5 - 6 eV), and excellent ferroelectric properties. Currently, HZO thin films are usually prepared by vacuum techniques such as pulsed laser deposition, atomic layer deposition, and chemical vapor deposition, but these methods require complex equipment and processes and are costly. Therefore, it is of great practical significance to develop a simple, low - cost, and highly controllable preparation method for HZO ferroelectric memristors. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention provides a preparation method of a flexible HZO ferroelectric memristor based on a full - solution method, which effectively overcomes the problems of difficult film formation and ferroelectric crystal structure regulation in the prior art, and has the advantages of simplicity and low cost. The technical solution is as follows:

[0005] A preparation method of a flexible HZO ferroelectric memristor based on a full - solution method, comprising the following steps:

[0006] S1. Prepare a flexible substrate layer: Use a mica sheet as the flexible substrate layer after cleaning;

[0007] S2. Prepare the bottom electrode layer: Mix graphene conductive coating and ethanol at a mass ratio of 1:1000, stir and ultrasonically treat them to delaminate graphene to obtain a mixture. Drop the obtained mixture evenly onto the upper surface of the flexible substrate layer prepared in S1, and after heating and curing, obtain the bottom electrode layer;

[0008] S3. Prepare the neural bionic layer:

[0009] S31. Prepare the HZO precursor solution: Mix HfCl4 powder, ZrCl4 powder, ethanol solution and deionized water at a weight ratio of 1:1:10:5, stir, and then ultrasonically treat to obtain the HZO precursor solution;

[0010] S32. Spin-coat the HZO precursor solution prepared in S31 onto the upper surface of the bottom electrode layer, and after high-temperature annealing, form the neural bionic layer;

[0011] S4. Prepare the top electrode: Drop Pt conductive paste evenly onto the upper surface of the neural bionic layer prepared in S3, and after heating and curing, form the top electrode.

[0012] Furthermore, in S1, the mica sheet is a smooth, crack-free and transparent mica sheet. Paste it on the operating table, and use pointed tweezers to peel it layer by layer until the remaining thickness of the mica sheet is 50μm ± 5μm. Ultrasonically clean it in acetone, ethanol and deionized water for 10 minutes each to obtain a clean mica sheet as the flexible substrate layer.

[0013] Furthermore, in S2, put graphene conductive coating and ethanol into a reagent bottle at a mass ratio of 1:1000, and place it on a magnetic stirrer to stir at a speed of 1500 rpm for 2 hours.

[0014] Furthermore, in S2, use an ultrasonic cleaner to ultrasonically treat for 1 hour to delaminate graphene to obtain a mixture.

[0015] Furthermore, in S2, the heating and curing process is specifically: put it into an oven and cure at 280°C for 30 minutes.

[0016] Furthermore, in S31, first pour HfCl4 powder and ZrCl4 powder into a reagent bottle, then add ethanol solution and deionized water simultaneously, and then stir with a magnetic stirrer at a speed of 1500 rpm for 2 hours, and then transfer it to an ultrasonic cleaner for ultrasonic treatment for 1 hour to obtain the HZO precursor solution.

[0017] Furthermore, the spin-coating process in S32 is specifically: first spin-coat at a speed of 500 rpm for 10 s, with a spin-coating thickness of 50 nm, then spin-coat at a speed of 3000 rpm for 20 s, with a spin-coating thickness of 10 nm, and then dry at 90°C for 10 minutes. Repeat this process three times.

[0018] Further, the high-temperature annealing process in S32 is specifically as follows: perform high-temperature annealing at 600 °C for 2 hours.

[0019] Further, in S4, use a dispensing needle with an inner diameter of 0.25 mm to evenly dot the Pt conductive paste onto the upper surface of the neural bionic layer obtained in S3.

[0020] Further, in S4, the process of heating and curing is specifically as follows: place it on a heating table and heat it to 80 °C for curing for 10 min.

[0021] Advantages of the present invention:

[0022] 1) Prepared by the all-solution method, without the need for complex and expensive vacuum equipment, greatly reducing the production cost. The preparation process is simple and controllable, and easy to operate;

[0023] 2) Select transparent mica sheets as the substrate of the flexible substrate layer, making the memristor have good flexibility and being suitable for fields such as wearable electronic devices;

[0024] 3) The oxygen competition mechanism at the GO and HZO thin film interface is one of the innovation points of the present invention; the oxygen-containing groups in the GO layer compete with the Hf and Zr ions in the HZO solution, making the HZO thin film and the GO layer reach stability at the interface by sharing oxygen atoms, promoting the transformation of HZO into the ferroelectric orthorhombic phase;

[0025] 4) Use graphene oxide (GO) as the bottom electrode layer. Due to the interaction of the interface oxygen competition mechanism, the interface chemical environment is regulated, and the interface characteristics of the device are improved; compared with common flexible substrates (such as polyimide or polyester films), mica has higher thermal tolerance and good high-temperature resistance performance;

[0026] 5) Through the optimization of the annealing temperature and the use of the interface oxygen competition mechanism, it is ensured that the formation of the required ferroelectric orthorhombic phase is achieved in the HZO thin film, while avoiding the formation of the non-ferroelectric active monoclinic phase, effectively regulating the crystal structure problem of the HZO thin film;

[0027] 6) By precisely regulating parameters such as the spin coating speed and the annealing temperature, the growth quality of the neural bionic layer can be effectively controlled. Description of the Drawings

[0028] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. For those of ordinary skill in the art, other related drawings can also be obtained based on these drawings without creative efforts.

[0029] Figure 1Schematic diagram of the flexible HZO ferroelectric memristor prepared by the all-solution method in the present invention.

[0030] Reference numerals in the figure: flexible substrate layer 1; bottom electrode layer 2; neurobionic layer 3; top electrode 4. Detailed implementation manners

[0031] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0032] As Figure 1 As shown, the flexible HZO ferroelectric memristor prepared by the all-solution method in the present invention includes: a flexible substrate layer 1, a bottom electrode layer 2, a neurobionic layer 3, and a top electrode 4.

[0033] Figure 1 The preparation method of the flexible HZO ferroelectric memristor based on the all-solution method as shown includes the following steps:

[0034] S1. Prepare the flexible substrate layer 1: Select a smooth and crack-free transparent mica sheet, paste it on the operating table, and peel it off layer by layer with pointed tweezers until the remaining mica sheet has a thickness of 50 μm (±5 μm). Then ultrasonically clean it in acetone, ethanol, and deionized water for 10 minutes each to obtain a clean mica sheet as the flexible substrate layer.

[0035] S2. Prepare the bottom electrode layer 2: Put graphene conductive coating and ethanol into a reagent bottle according to a mass ratio of 1:1000, place it on a magnetic stirrer and stir at a speed of 1500 rpm for 2 hours. Then use an ultrasonic cleaner to perform ultrasonic treatment for 1 hour to stratify graphene and obtain a mixture. Use a dropper to evenly drip the obtained mixture onto the upper surface of the flexible substrate layer 1 prepared in S1, and then put it into an oven and cure it at 280 °C for 30 minutes to obtain the bottom electrode layer;

[0036] S3. Prepare the neurobionic layer 3:

[0037] S31. Prepare the HZO precursor solution: Weigh equal amounts of HfCl4 and ZrCl4 powders and put them into a reagent bottle. Then simultaneously add ethanol solution and deionized water according to a volume ratio of 2:1. The weight ratio of HfCl4 powder, ZrCl4 powder, ethanol solution, and deionized water is 1:1:10:5. Place it on a magnetic stirrer and stir at a speed of 1500 rpm for 2 hours, and then transfer it to an ultrasonic cleaner for ultrasonic treatment for 1 hour to obtain the HZO precursor solution;

[0038] S32. Coat the HZO precursor solution prepared in S31 on the upper surface of the bottom electrode layer 2. First, spin-coat it at a speed of 500 rpm for 10 s, with a spin-coating thickness of 50 nm. Then, spin-coat it at a speed of 3000 rpm for 20 s, with a spin-coating thickness of 10 nm. Then, dry it at 90 °C for 10 minutes. Repeat this process three times. Finally, perform high-temperature annealing at 600 °C for 2 hours to form a neural bionic layer;

[0039] S4. Prepare the top electrode: Take the Pt conductive paste and evenly dot-coat it on the upper surface of the neural bionic layer prepared in S3 using a dispensing needle with an inner diameter of 0.25 mm. Then, place it on a heating table and cure it at 80 °C for 10 min to form the top electrode 4.

[0040] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a flexible HZO ferroelectric memristor based on a full solution method, characterized in that, It includes the following steps: S1. Prepare a flexible substrate layer: Use a mica sheet after cleaning as the flexible substrate layer; S2. Prepare a bottom electrode layer: Mix graphene conductive coating and ethanol in a mass ratio of 1:1000, stir, and perform ultrasonic treatment to delaminate graphene to obtain a mixture. Drop the obtained mixture evenly on the upper surface of the flexible substrate layer prepared in S1, and after heating and curing, obtain the bottom electrode layer; S3. Prepare a neural bionic layer: S31. Prepare an HZO precursor solution: Mix HfCl4 powder, ZrCl4 powder, ethanol solution, and deionized water in a weight ratio of 1:1:10:5, stir, and then perform ultrasonic treatment to obtain the HZO precursor solution; S32. Spin-coat the HZO precursor solution prepared in S31 on the upper surface of the bottom electrode layer, and perform high-temperature annealing to form a neural bionic layer; S4. Prepare a top electrode: Drop Pt conductive paste evenly on the upper surface of the neural bionic layer prepared in S3, and after heating and curing, form the top electrode.

2. The preparation method of a flexible HZO ferroelectric memristor based on a full solution method according to claim 1, characterized in that, In S1, the mica sheet is a smooth, crack-free, transparent mica sheet. Paste it on the operating table, and use pointed tweezers to peel it layer by layer until the remaining thickness of the mica sheet is 50μm ± 5μm. Ultrasonically clean it in acetone, ethanol, and deionized water for 10 minutes each to obtain a clean mica sheet as the flexible substrate layer.

3. The preparation method of a flexible HZO ferroelectric memristor based on a full solution process according to claim 1, characterized in that, In S2, put graphene conductive coating and ethanol in a mass ratio of 1:1000 into a reagent bottle, place it on a magnetic stirrer, and stir at a speed of 1500 rpm for 2 hours.

4. The preparation method of a flexible HZO ferroelectric memristor based on a full solution process according to claim 1, characterized in that, In S2, use an ultrasonic cleaner to perform ultrasonic treatment for 1 hour to delaminate graphene to obtain a mixture.

5. The preparation method of a flexible HZO ferroelectric memristor based on a full solution process according to claim 1, characterized in that, In S2, the heating and curing process is specifically: put it into an oven and cure it at 280°C for 30 minutes.

6. The preparation method of a flexible HZO ferroelectric memristor based on a full solution process according to claim 1, characterized in that, In S31, first pour HfCl4 powder and ZrCl4 powder into a reagent bottle, then add ethanol solution and deionized water simultaneously, and then stir with a magnetic stirrer at a speed of 1500 rpm for 2 hours, and then transfer it to an ultrasonic cleaner for ultrasonic treatment for 1 hour to obtain the HZO precursor solution.

7. The preparation method of a flexible HZO ferroelectric memristor based on a full solution method according to claim 1, characterized in that, The spin-coating process in S32 is specifically: first spin-coat at a speed of 500 rpm for 10 s, with a spin-coating thickness of 50 nm, then spin-coat at a speed of 3000 rpm for 20 s, with a spin-coating thickness of 10 nm, and then dry at 90°C for 10 minutes. Repeat this process three times.

8. The preparation method of a flexible HZO ferroelectric memristor based on the all-solution method according to claim 1, characterized in that The high-temperature annealing process in S32 is specifically: perform high-temperature annealing at 600°C for 2 hours.

9. The preparation method of a flexible HZO ferroelectric memristor based on a full solution process according to claim 1, characterized in that, In S4, use a dispensing needle with an inner diameter of 0.25 mm to evenly drop Pt conductive paste on the upper surface of the neural bionic layer prepared in S3.

10. The preparation method of a flexible HZO ferroelectric memristor based on the all-solution method according to claim 1, characterized in that, In S4, the heating and curing process is specifically: place it on a heating table and heat it to 80°C for curing for 10 minutes.

Images