Aluminum-scandium-nitrogen-based memristor, preparation method and application thereof

Abstract

The application provides an aluminum-scandium-nitrogen-based memristor, a preparation method and application thereof. 0.73 Sc 0.27 N ceramic as a sputtering target is sputtered on a Pt bottom electrode layer by high-energy radio frequency, so that the problems of deviation of Al and Sc proportion in reactive sputtering, low film performance and the like are avoided. The preparation method of the memristor is as follows: a substrate is cleaned and dried; an Al 0.73 Sc 0.27 N functional layer is grown on the Pt bottom electrode layer by a magnetron sputtering method; and a Pd top electrode layer is grown on the Al 0.73 Sc 0.27 N functional layer. Compared with a conventional memory device, the memristor has improved potential application in an artificial brain, develops a new biological neuron function in a simulated neuron system, has good performance, is a memory storage device with potential of simulating biological neuron behavior, good storage performance, low energy consumption and wider application prospect.

Description

Technical Field

[0001] This invention relates to the field of memory, specifically to a memristor based on aluminum scandium nitrogen, its preparation method, and its application. Background Technology

[0002] A memristor, short for memory resistor, is a circuit device that represents the relationship between magnetic flux and electric charge. While a memristor has the dimension of resistance, unlike a regular resistor, its resistance is determined by the amount of charge flowing through it. Therefore, by measuring the resistance of a memristor, the amount of charge flowing through it can be determined, thus enabling it to "memorize" charge. As the fourth fundamental circuit element, the memristor is widely used in information storage, logic operations, neural networks, machine learning, and many other fields, and has become a hot research topic.

[0003] Traditional memristors typically employ a "sandwich" structure, consisting of a top electrode layer, an intermediate functional layer (or intermediate dielectric layer), and a bottom electrode layer. They are usually fabricated using vacuum deposition techniques such as electron beam evaporation, thermal evaporation, and magnetron sputtering. Resistance is altered by adjusting the voltage between the two metal electrode layers to achieve low-resistance and high-resistance states. Current memristor research primarily focuses on oxide-based systems. The working principle of oxide-based memristors relies on the migration of oxygen vacancies under an electric field. However, due to the slow migration rate of oxygen vacancies, it is difficult to form conductive filaments between the top and bottom electrodes. Therefore, achieving a low-resistance state in oxide-based memristors is challenging, resulting in small switching ratios, high required bias voltages, poor stability, and excessive randomness. These disadvantages significantly limit the development of oxide memristors. Summary of the Invention

[0004] The purpose of this invention is to provide a memristor based on aluminum scandium nitrogen, its preparation method, and its application. This memristor is based on aluminum scandium nitrogen material Al. 0.73 Sc 0.27 Memristors made from N have excellent stability and can be used to simulate biological neurons.

[0005] This invention is implemented as follows: A memristor based on aluminum scandium nitrogen, the structure of which includes, from bottom to top, a Si substrate, a SiO2 layer, a Pt bottom electrode layer, and an Al layer. 0.73 Sc 0.27 N functional layer and Pd top electrode layer.

[0006] Preferably, in the above scheme, Al 0.73 Sc 0.27 The thickness of the N functional layer is 10nm to 20nm, and the thickness of the Pd top electrode layer is 50nm to 80nm.

[0007] Preferably, in the above scheme, the Pd top electrode layer includes several uniformly distributed layers in Al.0.73 Sc 0.27 Circular electrodes with diameters of 80–300 μm on the N-functional layer.

[0008] The method for fabricating a memristor based on aluminum scandium nitrogen provided by this invention includes the following steps:

[0009] (a) Pretreatment of the substrate; the substrate comprises, from bottom to top, a Si substrate, a SiO2 layer, and a Pt bottom electrode layer;

[0010] (b) Fix the substrate onto the substrate stage of the magnetron sputtering equipment cavity, and then apply Al... 0.73 Sc 0.27 The N-type target is fixed onto the target stage, and the cavity is evacuated to 2×10⁻⁶. -4 Pa, introduce Ar into the cavity at a flow rate of 50 sccm, adjust the slide valve to maintain the pressure in the cavity at 1 Pa, and open the control Al. 0.73 Sc 0.27 The RF source that ignites with an N-target is adjusted to power Al. 0.73 Sc 0.27 Nitrogen target ignition, pre-sputtering for 1-5 minutes, followed by formal sputtering for 5 minutes, then Al deposition on the Pt bottom electrode layer. 0.73 Sc 0.27 N functional layer;

[0011] (c) Place the mask on the surface where Al is formed 0.73 Sc 0.27 On the substrate of the N-functional layer, the cavity was evacuated to 2×10⁻⁶. - 4 Pa, introduce Ar into the cavity at a flow rate of 20-30 sccm, adjust the throttle valve to maintain the pressure in the cavity at 1 Pa, turn on the DC source controlling the Pd target ignition, adjust the DC source power to ignite the Pd target, pre-sputter for 1-2 minutes, then perform formal sputtering for 10-12 minutes, in Al 0.73 Sc 0.27 A Pd top electrode layer is formed on the N functional layer.

[0012] Preferably, in step (b), the power of the radio frequency source is adjusted to 150W; in step (c), the power of the DC source is adjusted to 10W.

[0013] Preferably, the prepared Al 0.73 Sc 0.27 The thickness of the N functional layer is 10nm to 20nm, and the thickness of the Pd top electrode layer is 50nm to 80nm.

[0014] Preferably, step (a) involves pretreating the substrate by sequentially placing the substrate into a beaker containing acetone, alcohol, and deionized water for ultrasonic cleaning, and then removing it and drying it with N2.

[0015] The memristor based on aluminum scandium nitrogen prepared in this invention can realize neuro-inspired functions, so as to facilitate the preparation of neuron-inspired devices.

[0016] This invention Al 0.73 Sc 0.27 N-ceramic targets are commercially available products.

[0017] This invention utilizes Al with a fixed component ratio 0.73 Sc 0.27 Nitrogen ceramics were used as sputtering targets to form Al 0.73 Sc 0.27 An N-functional layer was used to fabricate an aluminum scandium nitrogen-based memristor. During the fabrication process, Al... 0.73 Sc 0.27 High-energy direct radio frequency sputtering of N ceramic targets forms amorphous thin films. Compared with the existing reactive sputtering method (simultaneous sputtering of aluminum and scandium targets in a nitrogen atmosphere), this preparation process has the advantages of simple process and easy control of preparation conditions. It also avoids target poisoning and the coexistence of AlN and ScN in the film, thus avoiding many problems such as Al / Sc ratio deviation and poor film performance in reactive sputtering.

[0018] The memristor prepared by this invention uses wide-bandgap aluminum scandium nitride to optimize device performance, thus differing from traditional memory devices prepared using oxides. It exhibits excellent performance and can be used to simulate the function of biological neurons, making the application prospects of memristors in simulating the plasticity of biological neurons more extensive. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the memristor based on aluminum scandium nitrogen of the present invention.

[0020] Figure 2 This is a schematic diagram of 100 IV scan curves of the memristor based on aluminum scandium nitrogen in Embodiment 2 of the present invention.

[0021] Figure 3 This is a schematic diagram showing the turn-on speed (corresponding to (a)) and statistical distribution (corresponding to (b)) of the memristor based on aluminum scandium nitrogen according to the present invention.

[0022] Figure 4 This is a schematic diagram showing the turn-off speed (corresponding to (a)) and statistical distribution (corresponding to (b)) of the memristor based on aluminum scandium nitrogen according to the present invention.

[0023] Figure 5 This is a schematic diagram showing the application of a series of positive square waves of 1V, 2V, 3V, 4V, and 5V to the device. The corresponding output voltage is only generated when the voltage exceeds the threshold voltage.

[0024] Figure 6 This is a schematic diagram showing the application of a series of negative square waves of 1V, 2V, 3V, 4V, and 5V to the device. The corresponding output voltage is only generated when the voltage exceeds the threshold voltage. Detailed Implementation

[0025] The following examples are provided to further illustrate the present invention, but they do not limit the invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in this invention are conventional reagents, methods, and equipment in this technical field. However, they do not limit the invention in any way.

[0026] Example 1

[0027] like Figure 1 As shown, the aluminum scandium nitrogen-based memristor provided by this invention comprises, from bottom to top, a Si substrate, a SiO2 layer, a Pt bottom electrode layer, and an Al layer. 0.73 Sc 0.27 The device consists of an N-functional layer and a Pd top electrode layer. The Si substrate, SiO2 layer, and Pt bottom electrode layer constitute the entire device's substrate, which is readily available through direct purchase.

[0028] Al 0.73 Sc 0.27 The thickness of the N-functional layer is 10-20 nm, and the thickness of the Pd top electrode layer can be in the range of 50 nm to 80 nm; the Pd top electrode layer includes several uniformly distributed Al... 0.73 Sc 0.27 Circular electrodes with diameters of 80–300 μm on the N-functional layer.

[0029] Example 2

[0030] The method for fabricating a memristor based on aluminum scandium nitrogen provided by this invention includes the following steps:

[0031] (1) Use degreased cotton to gently wipe the surface of the Pt bottom electrode layer on the substrate with acetone and anhydrous ethanol in turn to ensure that there are no small particles such as dust attached to the surface and to initially remove the oil stains on the surface; then place the substrate in a beaker containing acetone and clean it in ultrasonic waves for 10 minutes to further clean the oil stains on the surface of the Pt bottom electrode layer; then place the ultrasonically cleaned substrate in a beaker containing anhydrous ethanol and clean it in ultrasonic waves for 10 minutes to wash away the acetone residue on the Pt bottom electrode layer; then use tongs to remove it and place it in a beaker containing deionized water and clean it in ultrasonic waves for 5 minutes to wash away the anhydrous ethanol; then remove it and blow it dry with N2.

[0032] (2) Fabrication of resistive switching dielectric layer:

[0033] First, polish the tablet press in the magnetron sputtering equipment chamber with sandpaper in a circular motion. Then, clean off any organic impurities with acetone, followed by cleaning off any remaining acetone with anhydrous ethanol. Finally, dry the surface of the tablet press with a nitrogen gun. Fix the substrate treated in step (1) onto the tablet press with silver paste and place it on the heating stage to prevent it from detaching during the experiment. Install the prepared tablet press into the magnetron sputtering equipment chamber and evacuate the chamber and gas path to 1×10⁻⁶. -4 Pa.

[0034] Al 0.73 Sc 0.27 Place the N-type target material on the target stage and secure the target sleeve. Open the gas filling valve and introduce 50 sccm of argon (Ar) gas. Simultaneously, rotate the target 5 revolutions and set the temperature to 400℃. Once the temperature display shows 400℃, continue heating for 10–15 minutes to ensure uniform heating of the tablet press stage. Adjust the throttle valve to achieve a chamber pressure of 3 Pa. Turn on the RF source and adjust the power to 150W. Observe the glow discharge to ensure the Al... 0.73 Sc 0.27 After the N-target material glows, the pressure inside the chamber is further adjusted to reach the required reaction pressure of 1 Pa for pre-sputtering. During pre-sputtering, the stability and consistency of the glow are observed. The baffle is closed during pre-sputtering to prevent unstable substances and impurities on the target material from contaminating the matrix. After 2–5 minutes, the baffle is opened, and the Al is sputtered. 0.73 Sc 0.27 Nitrogen material was deposited onto a Pt bottom electrode layer, with a thickness of approximately 15 nm. In-situ deposition was performed at 0°C with 50 sccm of argon gas supplied, releasing the hardening force while further ensuring the formation of a higher quality thin film. The Al formed in this step... 0.73 Sc 0.27 The N-functional layer is the resistive switching dielectric layer.

[0035] For Al 0.73 Sc 0.27 XRD and TEM tests on the N-functional layer revealed that the film is an amorphous thin film.

[0036] (3) Growth of Pd top electrode layer:

[0037] The mask was sequentially placed into beakers containing acetone, alcohol, and deionized water and ultrasonically cleaned. After removal, it was dried with N2. The resulting Al... 0.73 Sc 0.27 The substrate of the N-functional layer is fixed onto a photomask, which has uniformly distributed circular holes with a diameter of 100 μm. After the Pd top electrode layer is grown, the size of these circular holes is the size of the effective working area of ​​the memory.

[0038] The cavity was evacuated to below 5 Pa using a mechanical pump, and then evacuated to a vacuum of 2 × 10⁻⁶ using a molecular pump.-4 Pa. Open the gate valve to prevent the gas from directly contacting the molecular pump during the experiment. Open the gas filling valve to introduce Ar at a flow rate of 25 sccm. Adjust the gate valve to maintain the pressure in the chamber at 1 Pa. Turn on the DC power source and adjust the power to 10W to ignite the Pd target in the chamber. After 1 minute of pre-sputtering, open the baffle and perform formal sputtering for 15 minutes in Al. 0.73 Sc 0.27 A Pd top electrode layer is formed on the N functional layer.

[0039] By controlling the growth rate and growth time, the thickness of the Pd top electrode layer can be controlled within the range of 50 nm to 100 nm. The Pd electrode film is a series of circular electrode films with the same diameter as the circular holes on the photomask.

[0040] Performance testing

[0041] Combination Figure 1 The current-voltage characteristic curves of the memristor prepared in Example 2 were measured by applying a scanning voltage (Keithley 4200) to it, and the results are shown in [Figure 1]. Figure 2 .

[0042] The neuron simulation function of the device prepared in Example 2 was tested, and the results are shown in [Figure 2]. Figures 3-6 ,from Figures 3-6 It can be seen that memristor devices have a very fast switching speed and exhibit neuronal characteristics.

[0043] The novel high-performance memristor fabricated in this invention can be represented by the structure of Si / SiO2 / Pt / Al. 0.73 Sc 0.27 N / Pd is a typical bipolar volatile storage device.

Claims

1. The application of aluminum scandium nitrogen-based memristors in the fabrication of neuron-inspired devices, characterized by: The structure of the aluminum scandium nitrogen-based memristor includes, from bottom to top, a Si substrate, a SiO2 layer, a Pt bottom electrode layer, and an Al layer. 0.73 Sc 0.27 The N-functional layer and the Pd top electrode layer; the aluminum scandium nitrogen-based memristor is a bipolar volatile device; The method for fabricating the memristor based on aluminum scandium nitrogen includes the following steps: (a) Pretreatment of the substrate; the substrate comprises, from bottom to top, a Si substrate, a SiO2 layer, and a Pt bottom electrode layer; (b) Fix the substrate onto the substrate stage of the magnetron sputtering equipment cavity, and apply Al 0.73 Sc 0.27 The N-type target is fixed on the target stage, a vacuum is drawn, and argon gas is introduced into the cavity as the sputtering gas. The temperature is set to 400℃, and the control of Al is turned on. 0.73 Sc 0.27 The RF source for N-target ignition is adjusted to 150W, so that Al 0.73 Sc 0.27 The N-target material was ignited, and pre-sputtering was performed for 1-5 minutes, followed by formal sputtering, resulting in the formation of Al on the Pt bottom electrode layer. 0.73 Sc 0.27 N functional layer; set the temperature to 0℃, maintain argon gas flow, and perform in-situ deposition to obtain Al. 0.73 Sc 0.27 The N-functional layer is an amorphous thin film; (c) Place the mask on the surface where Al is formed 0.73 Sc 0.27 On the N-functional layer substrate, the cavity is evacuated, argon gas is introduced into the cavity, the DC source controlling the palladium target ignition is turned on, and the DC source power is adjusted to 10W to ignite the palladium target. Pre-sputtering is performed for 1-2 minutes, followed by formal sputtering on the Al... 0.73 Sc 0.27 A Pd top electrode layer is formed on the N functional layer.

2. The application according to claim 1, characterized in that, The Pd top electrode layer includes several uniformly distributed layers in Al. 0.73 Sc 0.27 Circular electrodes with diameters of 80–300 μm on the N-functional layer.

3. The application according to claim 1, characterized in that, The prepared Al 0.73 Sc 0.27 The thickness of the N functional layer is 10 nm to 20 nm, and the thickness of the Pd top electrode layer is 50 nm to 80 nm.

4. The application according to claim 1, characterized in that, Step (a) involves pretreating the substrate by sequentially ultrasonically cleaning it in acetone, alcohol, and deionized water, and then drying it with N2.

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