Nonvolatile ferroelectric memcapacitor device based on MFIFM structure and preparation method thereof

Abstract

The invention discloses a non-volatile ferroelectric memcapacitor device based on an MFIFM structure and a preparation method of the non-volatile ferroelectric memcapacitor device. The nonvolatile ferroelectric memcapacitor device comprises a first electrode, a first ferroelectric layer, an insulating layer, a second ferroelectric layer and a second electrode which are sequentially arranged in a stacked mode, different heterojunctions are formed on the two sides of the first ferroelectric layer and the two sides of the second ferroelectric layer, and by changing the polarization direction of the first ferroelectric layer and / or the second ferroelectric layer, different heterojunctions are formed on the two sides of the first ferroelectric layer and / or the second ferroelectric layer. And the potential barrier height and the potential barrier width at the interface of the first ferroelectric layer and / or the second ferroelectric layer are changed, so that charges in the device are changed, and information storage is realized. According to the nonvolatile ferroelectric memcapacitor device, a ferroelectric-insulator-ferroelectric novel laminated structure is used, the insulator is introduced into the memcapacitor so as to reduce leakage current, and the capacitance state of the device is read by using an alternating-current small signal, so that Joule heat from a circuit and the device is reduced, and the use power consumption of the device is reduced.

Description

Technical Field

[0001] The present invention particularly relates to a nonvolatile ferroelectric memristor device based on an MFIFM structure and a preparation method thereof, and belongs to the technical field of electronic devices. Background Art

[0002] The development of key technologies such as artificial intelligence (AI), big data, cloud computing, and the Internet of Things all rely on the development of the electronic information industry, especially information storage and processing technology.

[0003] Computers are the core of information storage and processing technology. However, current computers use the "von Neumann" architecture in which the processor and memory are separated. One of the core features of this architecture is the separation of storage and processing. Computer memory is used to store data and programs, while the processor is used to perform operations and manipulate data. This separation provides flexibility and versatility for computers, allowing programs to be loaded and executed on demand. In addition, "von Neumann" computers usually use a memory hierarchy, from cache to main memory and auxiliary storage devices, to achieve multi-level data storage. This hierarchy allows data to move between memories of different speeds and capacities to achieve efficient data access and processing. In von Neumann computers, instructions and data share the same storage and bus system. This means that instructions can be stored and transferred in memory like data, allowing the computer to perform various operations, including operating on instructions. Although this architecture has many advantages, it also has some defects and limitations, such as: (1) Storage problem: In the von Neumann computing architecture, data transmission between memory and processor is usually carried out through a shared bus. This leads to a bottleneck in data transmission speed, especially when processing large-scale data, the data transmission efficiency is low. (2) Energy efficiency problem: Due to the frequent data transmission between the computer's memory and processor, the energy efficiency problem also becomes prominent. This data transmission consumes a lot of energy, resulting in low energy efficiency of the computer. (3) Complexity: Von Neumann computer programs are usually executed sequentially, which makes certain complex parallel computing tasks difficult to implement. Modern computing needs are becoming more and more complex, requiring more parallel processing capabilities.

[0004] The neuromorphic computing architecture, which is inspired by the human brain's integrated storage and computing and parallel processing, and includes synapses and neurons, is considered an effective way to break through the "von Neumann bottleneck". The early success of neuromorphic computing largely relied on traditional electronic devices, especially spiking neural networks based on silicon-based complementary metal-oxide-semiconductor (CMOS) transistors, such as IBM's TrueNorth chip and the EU Human Brain Project's SpiNNaker project. Compared with traditional electronic devices, emerging electronic devices such as memristors have huge advantages in neuron construction and non-volatile storage.

[0005] Memristors are usually composed of a metal-insulator-metal (MIM) sandwich structure, including two layers of electrodes and one memristor functional layer. Their electrical properties are often closely related to the electrode layer and the functional layer. Based on different working mechanisms, memristors in a broad sense mainly include the following types: resistive random access memory (RRAM), phase-change memory (PCM), magnetic random access memory (MRAM), and ferroelectric memory.

[0006] The working principle of memristor is based on the charge distribution or ion migration phenomenon inside the material. When current passes through the memristor, charge redistribution or ion migration occurs inside the material, causing the resistance state to change. This change is proportional to the total amount of charge flowing through (or the time integral of the current), that is, the resistance of the memristor is determined by its historical current. After power is off, the charge or ion distribution remains unchanged, so the memristor "remembers" the last resistance state.

[0007] The development of memristors has promoted the hardware-level implementation of neuromorphic computing. Memristors use conductance to simulate synaptic weights, implement vector-matrix multiplication (VMM) operations through Ohm's law and Kirchhoff's current law, and are applied to neural network computing. However, due to the intrinsic Joule heating effect of current, huge heat consumption is inevitably generated in this process. In addition, as the size of the device decreases, the heat dissipation problem in the current-driven device will undoubtedly further affect the performance of the device, which is an important challenge in realizing large-scale storage and computing hardware.

[0008] Devices based on the principle of charge are an effective way to address the above challenges. Memristor devices are based on the principle of capacitance, and information is exchanged in the form of charge rather than current, so they have lower power consumption.

[0009] At present, most traditional non-volatile ferroelectric memristors are made of traditional perovskite oxide materials such as PZT and Hf0.5 Zr 0.5 The purpose of storage can be achieved by integrating ferroelectric materials between two electrodes to form a ferroelectric capacitor, or by introducing a ferroelectric layer into a field effect transistor to realize a non-volatile ferroelectric memristor device. The potential barrier can be regulated by selecting metal electrodes with different work functions, or by using a semiconductor as an electrode on one side. Such a non-volatile ferroelectric memristor device can achieve a storage effect by using electrodes with different work functions and changing the polarization state to regulate the potential barrier at the interface, so that the capacitance value measured by the ferroelectric memristor device under different polarization states with a small AC voltage has a significant change.

[0010] However, this approach uses conventional perovskite oxide materials such as PZT and Hf 0.5 Zr 0.5 O2 materials are non-volatile ferroelectric memristor devices made of ferroelectric materials. Since there are a large number of oxygen vacancies in the crystal structure of ferroelectric oxides, and almost all ferroelectric oxides are not compatible with mainstream semiconductor manufacturing processes. Therefore, there are some disadvantages in terms of cost and performance, mainly including the following points: (1) High cost: Since the ferroelectric material in this non-volatile ferroelectric memristor device is ferroelectric oxide, and almost all ferroelectric oxides are difficult to be compatible with mainstream semiconductor manufacturing processes, it is necessary to develop new supporting manufacturing processes, so the manufacturing cost is high. (2) Device stability: There are a large number of oxygen vacancies in ferroelectric oxides, and a large number of oxygen vacancies at the interface between ferroelectric materials and electrodes will produce interface effects, thereby affecting the data retention time of the memory device, so the device stability is relatively poor. (3) Energy consumption problem: Most non-volatile ferroelectric memory devices are memristor devices, which usually use conductivity or DC current to represent the information state, because the Joule heat of the circuit and device causes a large energy loss. (4) Environmental issues: Lead-containing materials such as PZT in traditional ferroelectric materials pollute the environment during preparation and production, cause harm to the human body, and cause lead poisoning. Therefore, research and development of lead-free piezoelectric ferroelectric materials has very important scientific significance and environmental effects. Summary of the invention

[0011] The main purpose of the present invention is to provide a non-volatile ferroelectric memristor device based on an MFIFM structure and a preparation method thereof, thereby overcoming the deficiencies in the prior art.

[0012] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes: The first aspect of an embodiment of the present invention provides a non-volatile ferroelectric memristor device based on an MFIFM structure, comprising: a first electrode, a first ferroelectric layer, an insulating layer, a second ferroelectric layer, and a second electrode stacked in sequence, wherein different heterojunctions are formed on both sides of the first ferroelectric layer and the second ferroelectric layer, and by changing the polarization direction of the first ferroelectric layer and / or the second ferroelectric layer, the barrier height and barrier width at the interface of the first ferroelectric layer and / or the second ferroelectric layer are changed, thereby changing the charge inside the device, thereby realizing information storage.

[0013] The second aspect of an embodiment of the present invention provides a method for preparing a non-volatile ferroelectric memristor device based on an MFIFM structure, comprising: sequentially manufacturing a first electrode, a first ferroelectric layer, an insulating layer, a second ferroelectric layer, and a second electrode that are stacked, wherein different heterojunctions are formed on both sides of the first ferroelectric layer and the second ferroelectric layer, and by changing the polarization direction of the first ferroelectric layer and / or the second ferroelectric layer, the barrier height and barrier width at the interface of the first ferroelectric layer and / or the second ferroelectric layer are changed, thereby changing the charge inside the device, thereby realizing information storage.

[0014] Compared with the prior art, the advantages of the present invention include: The present invention provides a non-volatile ferroelectric memristor device based on the three principles of ferroelectric polarization, capacitance principle and interface regulation. It uses III-V group ferroelectric nitride thin films compatible with mainstream semiconductor manufacturing processes as ferroelectric layers, which greatly reduces the preparation cost and also reduces the complexity and cost of the integration process. The nonvolatile ferroelectric memristor device based on the MFIFM structure provided by the embodiment of the present invention has no oxygen vacancies in the ferroelectric nitride, and the nitrogen vacancy formation energy is relatively high. Therefore, the nonvolatile ferroelectric memristor device in the present invention has excellent fatigue resistance, high stability and device uniformity, and does not contain heavy metals such as lead, and is environmentally friendly. The nonvolatile ferroelectric memristor device of the present invention uses a new ferroelectric-insulator-ferroelectric laminated structure, introduces an insulator into the memristor to reduce leakage current, and uses a small AC signal to read the capacitance state of the device, thereby reducing Joule heat from the circuit and the device, thereby reducing the power consumption of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a non-volatile ferroelectric memristor device based on an MFIFM structure provided in a typical implementation case of the present invention; Figure 2a , Figure 2b They are the phase change model of AlScN material in the polarization switching process and the hysteresis loop of AlScN material; Figure 3 This is the schematic diagram of the traditional MFIS structure ferroelectric memristor device; Figure 4 It is a schematic diagram of the state change of a non-volatile ferroelectric memristor device based on an MFIFM structure after voltage is applied, provided in a typical implementation case of the present invention; Figure 5 It is a schematic diagram of the structure of a preparation process of a non-volatile ferroelectric memristor device based on an MFIFM structure provided in a typical implementation case of the present invention. DETAILED DESCRIPTION

[0016] In view of the deficiencies in the prior art, the inventor of this case has proposed the technical solution of the present invention after long-term research and extensive practice. The technical solution, its implementation process and principle will be further explained as follows.

[0017] The first aspect of an embodiment of the present invention provides a non-volatile ferroelectric memristor device based on an MFIFM structure, comprising: a first electrode, a first ferroelectric layer, an insulating layer, a second ferroelectric layer, and a second electrode stacked in sequence, wherein different heterojunctions are formed on both sides of the first ferroelectric layer and the second ferroelectric layer, and by changing the polarization direction of the first ferroelectric layer and / or the second ferroelectric layer, the barrier height and barrier width at the interface of the first ferroelectric layer and / or the second ferroelectric layer are changed, thereby changing the charge inside the device, thereby realizing information storage.

[0018] Furthermore, the materials of the first ferroelectric layer and the second ferroelectric layer both include III-V group ferroelectric nitride.

[0019] Furthermore, the material of the first ferroelectric layer and the second ferroelectric layer includes AlScN.

[0020] Furthermore, the thickness of the first ferroelectric layer and the second ferroelectric layer is 1 nm to 100 nm.

[0021] Furthermore, the thickness of the insulating layer is 1 nm to 3 nm.

[0022] Furthermore, the material of the insulating layer includes AlN.

[0023] Furthermore, the first electrode and the second electrode are metal electrodes or semiconductor electrodes.

[0024] Furthermore, the material of the metal electrode includes at least one of Pt, Au, and Ag, and the material of the semiconductor electrode includes ITO or TiN.

[0025] Furthermore, the thickness of the first electrode / the second electrode is 20nm~200nm.

[0026] Furthermore, the nonvolatile ferroelectric memristor device based on the MFIFM structure further includes a substrate with a hexagonal structure, and the first electrode is stacked on the substrate.

[0027] Furthermore, the material of the substrate includes sapphire or gallium nitride.

[0028] The second aspect of an embodiment of the present invention provides a method for preparing a non-volatile ferroelectric memristor device based on an MFIFM structure, comprising: sequentially manufacturing a first electrode, a first ferroelectric layer, an insulating layer, a second ferroelectric layer, and a second electrode that are stacked, wherein different heterojunctions are formed on both sides of the first ferroelectric layer and the second ferroelectric layer, and by changing the polarization direction of the first ferroelectric layer and / or the second ferroelectric layer, the barrier height and barrier width at the interface of the first ferroelectric layer and / or the second ferroelectric layer are changed, thereby changing the charge inside the device, thereby realizing information storage.

[0029] In a more specific embodiment, the method for preparing the non-volatile ferroelectric memristor device based on the MFIFM structure includes: forming a first electrode by DC magnetron sputtering, forming a first ferroelectric layer, an insulating layer, and a second ferroelectric layer stacked in sequence on the first electrode by pulsed laser deposition, forming a second electrode on the second ferroelectric layer by DC magnetron sputtering to form a stacked structure, and patterning the stacked structure to form a plurality of non-volatile ferroelectric memristor device units.

[0030] Furthermore, the materials of the first ferroelectric layer and the second ferroelectric layer both include III-V group ferroelectric nitride.

[0031] Furthermore, the material of the first ferroelectric layer and the second ferroelectric layer includes AlScN.

[0032] Furthermore, the thickness of the first ferroelectric layer and the second ferroelectric layer is 1 nm to 100 nm.

[0033] Furthermore, the thickness of the insulating layer is 1 nm to 3 nm.

[0034] Furthermore, the material of the insulating layer includes AlN.

[0035] Furthermore, the first electrode and the second electrode are metal electrodes or semiconductor electrodes.

[0036] Furthermore, the material of the metal electrode includes at least one of Pt, Au, and Ag, and the material of the semiconductor electrode includes ITO or TiN.

[0037] Furthermore, the thickness of the first electrode / the second electrode is 20nm~200nm.

[0038] The technical solution, its implementation process and principles, etc. will be further explained below in conjunction with the accompanying drawings and specific implementation cases. Unless otherwise specified, the pulsed laser deposition system (PLD) and corresponding processes, magnetron sputtering equipment and processes, photolithography, etching and other processes and equipment used in the embodiments of the present invention are all known in the art.

[0039] In a typical implementation case, please refer to Figure 1 A non-volatile ferroelectric memristor device based on III-V group ferroelectric nitrides includes a stacked substrate with a hexagonal structure, a first electrode (also referred to as a bottom electrode, the same below), a first ferroelectric layer, an ultra-thin insulating layer, a second ferroelectric layer and a second electrode (also referred to as a top electrode, the same below). The MFIFM structure forms different heterojunctions on both sides of the first ferroelectric layer / second ferroelectric layer. The capacitance can be continuously adjusted by quasi-continuously inverting the domains in the ferroelectric layer material, thereby forming a memristor device with good memristor characteristics.

[0040] Specifically, the substrate may be a sapphire substrate or a gallium nitride substrate. Specifically, the first electrode and the second electrode may be metal electrodes or semiconductor electrodes. The material of the metal electrode includes at least one of Pt, Au, and Ag. The material of the semiconductor electrode includes ITO or TiN. More specifically, different semiconductor electrodes may be selected as the second electrode according to the integration needs and application requirements. For example, when the oxide semiconductor ITO is used as the second electrode, due to the optical properties of ITO, it can be used in optical systems and is expected to achieve key applications such as optical storage and computing integration and even green new display. The thickness of the first electrode / the second electrode is 20nm~200nm. Specifically, the materials of the first ferroelectric layer and the second ferroelectric layer both include III-V group ferroelectric nitrides. For example, the materials of the first ferroelectric layer and the second ferroelectric layer are both AlScN, and the thickness of the first ferroelectric layer and the second ferroelectric layer is 1nm~100nm. Specifically, the thickness of the insulating layer is 1nm~3nm, and the material of the insulating layer may be AlN.

[0041] Specifically, the AlScN material is characterized by spontaneous polarization, and the direction of its spontaneous polarization can be reversed with the reversal of the external field polarity. When the external electric field is removed, its polarization direction can be maintained. Figure 2a As shown, the polarization of AlScN material and the applied electric field are shown as follows Figure 2b The nonlinear relationship shown is called a hysteresis loop. Figure 2bWhere Ec is the coercive field, which is the minimum electric field that causes the ferroelectric polarization to flip, and Pr is the remnant polarization, which is the polarization strength maintained in the ferroelectric crystal when the electric field is zero. At the maximum applied electric field, the ferroelectric polarization reaches saturation, and the ratio of the remnant polarization to the saturation polarization is called the rectangularity of the hysteresis loop. Usually, the ferroelectric properties of a material only exist within a specific temperature range. As the temperature increases, the ferroelectric material will transform into a paraelectric state, and this transition point is called the Curie temperature.

[0042] The structure of the traditional ferroelectric memristor device is the MFIS structure. The stacked structure of the ferroelectric capacitor and the metal / insulator / semiconductor (MIS) varactor diode in series is designed as a ferroelectric memristor. By modulating the polarization direction of the ferroelectric layer, the semiconductor enters different states such as depletion and accumulation, thereby changing the capacitance state of the device, such as Figure 3 As shown, since one side is a semiconductor electrode, its preservation performance will decrease. The present invention improves the stability of the device by introducing an AlN insulating layer.

[0043] The present invention uses two ferroelectric layers separated by an insulating layer. This structure is a new design in the field of memristors. By applying voltage, the device of the present invention will appear as follows: Figure 4 There are four different stages as shown. If the initial state of the device is set to both ferroelectric layers polarized upward, by applying voltage at both ends of the device, the device will change from both ferroelectric layers polarized upward to one layer polarized upward and the other layer polarized downward, so that the capacitance value changes. Therefore, the device has four different stages. Not only that, the quasi-continuous reversal characteristics of the domains in the ferroelectric material can achieve continuous adjustment of the capacitance, achieving twice the number of storage states of ordinary memcapacitor devices. And because it is a memcapacitor device, we have no special requirements for the contact between the ferroelectric material and the metal electrode, either ohmic contact or Schottky contact is fine.

[0044] Compared with common organic ferroelectric memristor devices, the defects of organic materials themselves make the devices unable to withstand high temperatures and have poor cycle performance. Compared with current oxide ferroelectric memristor devices, most oxide ferroelectric materials are perovskite structure materials that are not compatible with existing mainstream semiconductor processes.

[0045] The AlScN ferroelectric memristor provided in the embodiment of the present invention can work stably at temperatures up to 600°C. This feature enables it to maintain data integrity and reliability in extreme environments, especially in situations where high-temperature data storage is required, such as logging while drilling technology in oil drilling. The emergence of AlScN ferroelectric memristors is expected to solve the problem of failure of traditional storage devices in high-temperature environments and improve the reliability of data storage and the durability of equipment. In addition, the AlScN ferroelectric memristor can be more closely integrated with the processor at high temperatures, reducing data transmission time, thereby improving computing speed and efficiency. This efficient integration not only improves the performance of AI systems, but also provides new design and application possibilities for AI systems operating in harsh environments.

[0046] Specifically, a non-volatile ferroelectric memristor device based on a ferroelectric AlScN material MFIFM structure provided in an embodiment of the present invention is a technology that utilizes the ferroelectric properties of the AlScN material to regulate the interface potential barrier to cause charge changes and thus store information. It expresses the two states of '0' and '1' stored in a computer as different polarization states of the ferroelectric layer, and by regulating the polarization direction of the first / second ferroelectric layer, the barrier height and barrier width at the interface change, thereby achieving capacitance control of the device. Combined with the property of the first / second ferroelectric layer having residual polarization strength, it can not only read data when power is on, but also save data after the device is powered off, thereby reducing energy consumption and forming a non-volatile ferroelectric memristor device with a high switching ratio.

[0047] The present invention can also realize continuous adjustment of capacitance by quasi-continuous reversal characteristics of domains in the ferroelectric material of the first / second ferroelectric layer, thereby forming a memcapacitor device with good memcapacitor characteristics. The present invention combines the advantages of the ferroelectric properties of AlScN materials and memcapacitor technology, utilizes the residual polarization characteristics of ferroelectric materials to realize non-volatile storage, thereby reducing energy consumption, utilizes small signal AC voltage to read capacitance to generate only a very small AC current, thereby reducing energy consumption, utilizes the polarization reversal characteristics of ferroelectric materials to regulate the potential barrier at the interface to cause charge changes, thereby obtaining a high capacitance state ratio (i.e., effective capacitance switching ratio, the ratio of maximum steady-state capacitance to minimum steady-state capacitance), utilizes the characteristics of small volume of memcapacitor and easy three-dimensional integration of two-terminal devices to realize high-density storage, thereby increasing storage capacity, and utilizes the quasi-continuous reversal characteristics of domains in ferroelectric materials to realize continuous adjustment of capacitance, thereby not only meeting the needs of high-density and low-energy storage, but also meeting the needs of neuron-like devices of low-energy storage and computing integrated computing architecture.

[0048] In a typical implementation case, the nonvolatile ferroelectric memristor device is a ferroelectric-insulating layer-ferroelectric structure, and the preparation method of the nonvolatile ferroelectric memristor device may include the following process: First, the substrate is ultrasonically cleaned. A common sapphire substrate is selected as the substrate. Then, a pulsed laser deposition device (PLD) is used to grow the first electrode (the first electrode can be any metal electrode or semiconductor electrode, such as Pt, Au, Ag, etc., with a thickness of 20nm-200nm). After in-situ annealing of the first electrode, a first ferroelectric layer is grown (the first ferroelectric layer is made of AlScN and has a thickness of 1 nm to 100 nm); Then, an extremely thin insulating layer is grown (the thickness of the insulating layer is 1 nm to 3 nm, and the material of the insulating layer may be AlN, etc.); Growing a second ferroelectric layer on the insulating layer (the second ferroelectric layer is made of AlScN and has a thickness of 1 nm to 100 nm); Finally, grow the second electrode (the second electrode can be any metal electrode or semiconductor electrode, such as Pt, Au, Ag, ITO electrode, etc., with a thickness of 20nm-200nm); Next, positive photoresist AZ5214 is sprayed on the surface of the second electrode, and the device is patterned through photolithography and development technology (any photolithography machine model can be used, and photolithography machines with different resolutions can be selected according to the actual application requirements for the size of the unit device). After coating and photolithography, an NLD etcher is used with the photoresist as a mask to etch away materials other than those that are not patterned. After etching, the sample is immersed in an acetone solution for 12 hours, and a rubber-tipped dropper is used to gently blow on the surface in the solution, and ultrasonically applied for 30s×4 to completely remove the photoresist to obtain the required unit non-volatile ferroelectric memristor device. Finally, the sample is rinsed with isopropyl alcohol and deionized water several times, respectively, and dried with nitrogen to complete the preparation.

[0049] Example 1 This embodiment mainly uses MA6 double-sided alignment lithography machine, pulse laser deposition equipment (PLD) and other instruments. The main process steps are: substrate preparation, pulse laser deposition equipment to grow AlScN ferroelectric film, pulse laser deposition equipment to grow AlN film, DC magnetron sputtering system to sputter TiN film, glue coating, photolithography, development, lift-off, NLD etching, See also Figure 5 A method for preparing a non-volatile ferroelectric memristor device based on AlScN material comprises the following steps: 1) Substrate preparation: The substrate used in the embodiment of the present invention is a sapphire substrate oriented to the c-axis (0001), with a thickness of 0.4 μm and a length and width of 10 mm×10 mm.

[0050] Since the metal film is grown on the surface of the substrate using a pulsed laser deposition device, the roughness and smoothness of the substrate surface directly determine the uniformity and smoothness of the subsequent film coating. If the surface is not clean, it may cause the film to fall off during the subsequent process or cleaning. In view of the above reasons, the substrate cleaning steps usually taken are as follows: first, take a glass beaker and a polytetrafluoroethylene basket of appropriate capacity, rinse them repeatedly with deionized water, and blow dry the excess water on the inner wall of the beaker and the basket with a nitrogen gun; then take out the sample and put it in the basket, add acetone solution to the beaker, immerse the basket and the sample in the solution, and then put it into an ultrasonic cleaner for cleaning for 5 minutes; repeat this operation 3 times; then replace the isopropanol solution to clean the substrate for 5 minutes, repeat 3 times, and the other operations are the same as the previous step; finally, rinse the substrate repeatedly with deionized water, blow dry it with nitrogen, and put it in the sample box.

[0051] 2) A pulsed laser deposition system (PLD) was used to grow a TiN film on the substrate as a bottom electrode: a TiN film with a thickness of 20 nm was grown using a pulsed laser deposition system with a growth rate of 0.1 nm / min, a growth time of 200 min, an operating temperature of 700°C, a laser frequency of 1 Hz, and a laser energy of 350 mJ.

[0052] 3) Using a pulsed laser deposition system (PLD) to grow an AlScN ferroelectric film on the bottom electrode as the first ferroelectric layer: Using a pulsed laser deposition system to grow an AlScN ferroelectric film with a thickness of 8 nm, the growth rate is 0.3 nm / min, the growth time is 27 min, the operating temperature is 400°C, the laser frequency is 1 Hz, and the laser energy is 300 mJ.

[0053] 4) Using a pulsed laser deposition system (PLD) to grow an AlN film as an insulating layer on the first ferroelectric layer: Using a pulsed laser deposition system to grow an AlScN ferroelectric film with a thickness of 2 nm, the growth rate is 0.1 nm / min, the growth time is 20 min, the operating temperature is 400°C, the laser frequency is 1 Hz, and the laser energy is 300 mJ.

[0054] 5) A pulsed laser deposition system (PLD) was used to grow an AlScN ferroelectric film as the second ferroelectric layer on the insulating layer: an AlScN ferroelectric film with a thickness of 8 nm was grown using a pulsed laser deposition system with a growth rate of 0.3 nm / min, a growth time of 27 min, an operating temperature of 400°C, a laser frequency of 1 Hz, and a laser energy of 300 mJ.

[0055] 6) A TiN film is grown on the second ferroelectric layer by magnetron sputtering as a top electrode: a TiN film with a thickness of 20 nm is sputtered by a DC magnetron sputtering system as a top electrode.

[0056] 7) Photolithography and development: Spray positive photoresist AZ5214 and use MA6 double-sided alignment photolithography machine (in fact, any model of photolithography machine can be used, depending on the size of the unit device) to make the required device size. The specific photolithography parameters are as follows: surface pretreatment and adhesive coating (HMDS); AZ5214 coating forward rotation of 600 rpm for 5 s, backward rotation of 3000 rpm for 30 s; Hard mode, 0.8 s; development using 3038, 45 s (start shaking after 10 s), DI water fixation for 1 min, blow dry with nitrogen gun; microscopy objective lens 5x and 20x.

[0057] 8) NLD etching: After the previous step, the preparation of the ferroelectric memristor device unit patterning has been completed. Next, the independent unit non-volatile ferroelectric memristor device structure is prepared by etching downward. Using photoresist as a mask, only the NLD etcher is needed to etch away the thin film except the upper unit device patterning at one time, and the etching time is set to 50s.

[0058] 9) Removal of residual photoresist: Since the etching process does not completely etch away the photoresist, the sample needs to be immersed in an acetone solution for 12 hours, and a rubber-tipped dropper is used to gently blow on the surface in the solution, and ultrasonically applied for 30 seconds × 4 to completely remove the photoresist. The sample is then rinsed with isopropyl alcohol and water respectively, and finally dried with nitrogen.

[0059] Compared with the ferroelectric oxide used in the traditional non-volatile ferroelectric memristor device, the present invention provides a non-volatile ferroelectric memristor device based on the three principles of ferroelectric polarization, capacitance principle and interface regulation, and adopts III-V group ferroelectric nitride film compatible with the mainstream semiconductor manufacturing process as the ferroelectric layer, which greatly reduces the preparation cost and also reduces the complexity and cost of the integrated process. At the same time, there is no oxygen vacancy in the ferroelectric nitride, and the nitrogen vacancy formation energy is relatively high. Therefore, the non-volatile ferroelectric memristor device in the present invention has excellent fatigue resistance, high stability and device uniformity, and does not contain heavy metals such as lead, and has no pollution to the environment. In addition, the non-volatile ferroelectric memristor device in the present invention uses a new type of laminated structure such as ferroelectric-insulator-ferroelectric, introduces an insulator into the memristor to reduce the leakage current, and uses a small AC signal to read the capacitance state of the device, thereby reducing the Joule heat from the line and the device, thereby reducing the power consumption of the device.

[0060] The non-volatile ferroelectric memristor device of the present invention meets different application requirements and integration needs by selecting different semiconductor electrodes (at the same time, because it is a III-V ferroelectric nitride, it is compatible with the current mainstream semiconductor process and can reduce the difficulty of integration). For example, when a transparent semiconductor material such as ITO is used as the upper electrode, it can be used in an optical system due to the optical properties of ITO, and is expected to realize key applications such as new light field control, optoelectronic hybrid storage and computing, and new displays.

[0061] The non-volatile memcapacitor device based on AlScN ferroelectric material provided by the present invention is of great significance for realizing on-chip integration of storage and computing integrated embedded systems. The memcapacitor device is based on the principle of capacitance, and information interacts in the form of charge rather than current, so it has lower power consumption. In addition, the non-volatile memcapacitor device based on AlScN ferroelectric material provided by the present invention only needs to change the electrodes with different work functions in theoretical design to realize low energy consumption, high switching ratio, and fast response speed memcapacitor devices that can be applied in different scenarios. Since it is compatible with the current nitride semiconductor process, the non-volatile ferroelectric memcapacitor device can be integrated in different nitride electronic systems, thereby simplifying the difficulty of nitride on-chip integration.

[0062] For manufacturers, the difficulty of integrating the non-volatile memory device based on AlScN ferroelectric material provided by the present invention is reduced, and the complexity of the process is reduced, thereby reducing the production cost of the manufacturer. For consumers, low-power storage devices and even low-power storage and computing integrated embedded systems can improve the performance of the equipment while reducing the subsequent use costs.

[0063] It should be understood that the above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A non-volatile ferroelectric memristor device based on an MFIFM structure, characterized in that: include: A first electrode, a first ferroelectric layer, an insulating layer, a second ferroelectric layer, and a second electrode are stacked in sequence, and different heterojunctions are formed on both sides of the first ferroelectric layer and the second ferroelectric layer. By changing the polarization direction of the first ferroelectric layer and / or the second ferroelectric layer, the barrier height and barrier width at the interface of the first ferroelectric layer and / or the second ferroelectric layer are changed, and the charge inside the device is changed, thereby realizing information storage.

2. The nonvolatile ferroelectric memristor device based on the MFIFM structure according to claim 1, characterized in that: The materials of the first ferroelectric layer and the second ferroelectric layer both include III-V group ferroelectric nitride; Preferably, the material of the first ferroelectric layer and the second ferroelectric layer includes AlScN; Preferably, the thickness of the first ferroelectric layer and the second ferroelectric layer is 1 nm to 100 nm.

3. The nonvolatile ferroelectric memristor device based on the MFIFM structure according to claim 1, characterized in that: The thickness of the insulating layer is 1nm~3nm; Preferably, the material of the insulating layer includes AlN.

4. The nonvolatile ferroelectric memristor device based on the MFIFM structure according to claim 1, characterized in that: The first electrode and the second electrode are metal electrodes or semiconductor electrodes; Preferably, the material of the metal electrode includes at least one of Pt, Au, and Ag, and the material of the semiconductor electrode includes ITO or TiN; Preferably, the thickness of the first electrode / the second electrode is 20nm~200nm.

5. The nonvolatile ferroelectric memristor device based on the MFIFM structure according to claim 1, characterized in that: It also includes a substrate having a hexagonal structure, and the first electrode is stacked on the substrate; Preferably, the material of the substrate includes sapphire or gallium nitride.

6. A method for preparing a non-volatile ferroelectric memristor device based on an MFIFM structure, characterized in that: include: A first electrode, a first ferroelectric layer, an insulating layer, a second ferroelectric layer and a second electrode are stacked in sequence, and different heterojunctions are formed on both sides of the first ferroelectric layer and the second ferroelectric layer. By changing the polarization direction of the first ferroelectric layer and / or the second ferroelectric layer, the barrier height and barrier width at the interface of the first ferroelectric layer and / or the second ferroelectric layer are changed, and the charge inside the device is changed, thereby realizing information storage.

7. The method for preparing a nonvolatile ferroelectric memristor device based on an MFIFM structure according to claim 6, characterized in that: include: A first electrode is formed by direct current magnetron sputtering, a first ferroelectric layer, an insulating layer, and a second ferroelectric layer are sequentially stacked on the first electrode by pulsed laser deposition, a second electrode is formed on the second ferroelectric layer by direct current magnetron sputtering, thereby forming a stacked structure, and the stacked structure is patterned to form a plurality of non-volatile ferroelectric memory device units.

8. The method for preparing a nonvolatile ferroelectric memristor device based on an MFIFM structure according to claim 6, characterized in that: The materials of the first ferroelectric layer and the second ferroelectric layer both include III-V group ferroelectric nitride; Preferably, the material of the first ferroelectric layer and the second ferroelectric layer includes AlScN; Preferably, the thickness of the first ferroelectric layer and the second ferroelectric layer is 1 nm to 100 nm.

9. The method for preparing a nonvolatile ferroelectric memristor device based on an MFIFM structure according to claim 6, characterized in that: The thickness of the insulating layer is 1nm~3nm; Preferably, the material of the insulating layer includes AlN.

10. The method for preparing a nonvolatile ferroelectric memristor device based on an MFIFM structure according to claim 6, characterized in that: The first electrode and the second electrode are metal electrodes or semiconductor electrodes; Preferably, the material of the metal electrode includes at least one of Pt, Au, and Ag, and the material of the semiconductor electrode includes ITO or TiN; Preferably, the thickness of the first electrode / the second electrode is 20nm~200nm.

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