Memristor based on Mn-doped GeSe-based magnetic semiconductor film and preparation method

Abstract

The invention provides a memristor based on a Mn-doped GeSe-based magnetic semiconductor thin film and a preparation method, and relates to the technical field of memristors, the memristor comprises a substrate layer, a resistive random dielectric layer and a top electrode layer which are sequentially arranged from bottom to top, the resistive random dielectric layer is the Mn-doped GeSe-based magnetic semiconductor thin film, and the top electrode layer is arranged between the substrate layer and the resistive random dielectric layer. The thickness of the Mn-doped GeSe-based magnetic semiconductor thin film ranges from 100 nm to 700 nm. According to the memristor disclosed by the invention, the Mn-doped GeSe-based thin film with relatively strong ferromagnetism is used as a resistive change dielectric layer material, and the magnetism of the material is introduced into a resistance change process of a device, so that the memristor shows typical resistance conversion characteristics and biological synapse characteristics; and the memristor disclosed by the invention shows a resistance transformation characteristic with an adjustable magnetic field and biological synaptic plasticity, and shows huge application potential in multifunctional nonvolatile memristor devices and neuromorphic electronic devices.

Description

Technical Field

[0001] The present invention relates to the technical field of memristors, and in particular to a memristor based on an Mn-doped GeSe-based magnetic semiconductor thin film and a preparation method thereof. Background Art

[0002] A memristor is a circuit device that relates magnetic flux and electric charge. Due to the characteristics of low energy consumption, high-speed operation and high storage density, the resistive random access memory device based on a memristor is expected to be used in a new generation of non-volatile memory devices.

[0003] The existing research on the dielectric layer of memristors mainly focuses on traditional non-layered metal oxides, and the performance of the prepared memristors still needs to be improved. Therefore, finding new materials suitable for memristors and preparing new memristors are problems that those skilled in the art urgently need to solve. Summary of the Invention

[0004] The purpose of the present application is to provide a memristor based on an Mn-doped GeSe-based magnetic semiconductor thin film and a preparation method thereof, so as to solve the technical problem that the performance of the existing memristors needs to be improved.

[0005] To achieve the above purpose, the technical solution adopted by the present application is as follows: In the first aspect, the present application provides a memristor based on an Mn-doped GeSe-based magnetic semiconductor thin film, including a substrate layer, a resistive switching dielectric layer and a top electrode layer arranged in sequence from bottom to top, wherein the resistive switching dielectric layer is an Mn-doped GeSe-based magnetic semiconductor thin film, and the thickness of the Mn-doped GeSe-based magnetic semiconductor thin film is 100 nm to 700 nm.

[0006] In one or more embodiments of the present application, the concentration of Mn in the Mn-doped GeSe-based magnetic semiconductor thin film is 1%.

[0007] In one or more embodiments of the present application, the top electrode layer is Ag, the thickness of the top electrode layer is 10 to 100 nm, and each top electrode is a circular electrode with a diameter of 100 μm.

[0008] In one or more embodiments of the present application, the substrate layer includes an Si layer, an SiO2 layer and a Pt layer arranged in sequence from bottom to top, wherein the Pt layer is located between the Mn-doped GeSe-based magnetic semiconductor thin film and the SiO2 layer.

[0009] In the second aspect, the present application also provides a preparation method of a memristor based on an Mn-doped GeSe-based magnetic semiconductor thin film, including: S1: Cutting and cleaning the Si / SiO2 / Pt substrate layer; S2: Placing the sample: Take GeSe powder and MnCl2 powder as growth sources and place them in the middle position of the corundum sheet according to a certain ratio. Then, place the corundum sheet at the high-temperature zone position in a two-temperature-zone tube furnace, and place the Si / SiO2 / Pt substrate layer obtained in step S1 at the low-temperature zone position. Set the temperatures of the high-temperature zone and the low-temperature zone to 750 °C - 800 °C and 150 °C - 250 °C respectively, and keep them at the set temperatures for a certain period of time after reaching the temperatures. The entire growth process is carried out in an Ar / H2 mixed atmosphere; S3: Growing the thin film: Start the tube furnace. After the growth is completed, let the tube furnace cool down to room temperature naturally. Take a sample to obtain the GeMnSe magnetic semiconductor thin film for standby; S4: Growing the electrode: Use the metal hard mask method to prepare a top electrode on the upper surface of the GeMnSe thin film by radio frequency magnetron sputtering. The sputtering temperature is room temperature. After the top electrode sputtering is completed, perform rapid annealing in an N2 atmosphere to obtain a magnetic memristor with an Ag / GeMnSe / Pt structure.

[0010] In one or more embodiments of the present application, in step S2, the distance between the Si / SiO2 / Pt substrate layer and the growth source powder on the corundum sheet is 25 cm.

[0011] In one or more embodiments of the present application, in step S2, the temperatures of the high-temperature zone and the low-temperature zone are set to 770 °C and 200 °C respectively. The growth curve of the high-temperature zone is from 50 °C to 400 °C in 70 min, from 400 °C to 770 °C in 60 min, and keep at 770 °C for 60 min - 150 min; the growth curve of the low-temperature zone is from 30 °C to 200 °C in 130 min, and keep at 200 °C for 60 min - 150 min.

[0012] In one or more embodiments of the present application, in the Ar / H2 mixed atmosphere, the proportion of Ar is 5%, and the gas flow rate is 10 sccm - 50 sccm.

[0013] In one or more embodiments of the present application, in step S4, when growing the electrode, the deposition time is 10 min, the rapid annealing temperature is 400 °C, and the time is 120 s.

[0014] Based on the above technical solutions, a memristor based on an Mn-doped GeSe-based magnetic semiconductor thin film and a preparation method thereof according to the present application at least have the following beneficial technical effects: The memristor based on the Mn-doped GeSe-based magnetic semiconductor thin film of the present application uses a Mn-doped GeSe-based thin film with strong ferromagnetism as the resistive switching dielectric layer material, introducing the magnetism of the material into the resistance change process of the device, enabling the memristor to exhibit typical resistance switching characteristics and biological synaptic characteristics. Moreover, the memristor of the present application exhibits magnetic-field-tunable resistance switching characteristics and biological synaptic plasticity. In particular, stable non-volatile resistance switching characteristics can be achieved when a magnetic field of 1000 Oe is applied, with a 6 high resistance switching ratio (R OFF / R ON ) and excellent high and low resistance state time retention ability (~10 4 s), which is due to the driven migration of Ag atoms in the memristor under the action of electric and magnetic fields. The memristor of the present application shows great application potential in multifunctional non-volatile memristive devices and neuromorphic electronic devices.

[0015] On the other hand, the preparation method of the memristor based on the Mn-doped GeSe-based magnetic semiconductor thin film of the present application combines chemical vapor deposition method and magnetron sputtering method to prepare a memristor with an Ag / GeMnSe / Pt structure using a Mn-doped GeSe thin film with strong ferromagnetism as the resistive switching dielectric layer material. The preparation method has low requirements for equipment, does not require a high-vacuum environment and complex reactants to participate, and can react in an Ar / H2 mixed atmosphere under a general level of vacuum, which can greatly reduce the preparation cost. Moreover, the method is simple and easy to implement, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 is a schematic structural diagram of the GeMnSe magnetic memristor prepared in Embodiments 1 to 6 of the present invention.

[0018] Figure 2 is the resistive switching performance diagram of the memristor prepared in Embodiments 1 to 6 of the present application; among them, Figure 2 (a) is the resistive switching performance diagram of the memristor with different Mn doping concentrations in the GeMnSe resistive switching dielectric layer in Embodiment 6 of the present invention; Figure 2 (b) is the resistive switching performance diagram of the memristor with different thicknesses of the GeMnSe layer as the resistive switching dielectric layer prepared in Embodiments 2 to 5; Figure 2(c)Rheological property diagrams of GeMnSe magnetic memristors with different top electrode materials prepared in Example 1.

[0019] Figure 3 It is a schematic diagram of the structural characterization of the GeMnSe magnetic memristor. Among them, Figure 3 (a)is the I-V logarithmic curve graph of the device Ag / GeMnSe / Pt prepared in Example 3; Figure 3 (b)is the cross-sectional SEM micrograph of the GeMnSe / Pt / Si structure in Example 3; Figure 3 (c)is the atomic force microscope (AFM) image of the GeMnSe thin film on the Pt / Si substrate.

[0020] Figure 4 It is a schematic diagram of the structural characterization of the GeMnSe magnetic memristor. Among them, Figure 4 (a-e)are the TEM-EDS elemental mapping images of Si, Ge, Mn, Se, and Pt; Figure 4 (f)is the HRTEM image of the GeMnSe layer; Figure 4 (g)is Figure 4 the IFFT image corresponding to the four regions I-IV in (f); Figure 4 (h)is the SAED image of the GeMnSe thin film.

[0021] Figure 5 It is a schematic diagram of the structural characterization of the GeMnSe magnetic memristor. Among them, Figure 5 (a)is the EDS spectrogram in the GeMnSe layer; Figure 5 (b)is the XRD spectrogram of the GeMnSe thin film; Figure 5 (c)is the Raman spectrogram of the GeMnSe thin film.

[0022] Figure 6 It is a schematic diagram of the device for I-V testing of the GeMnSe-based magnetic memristor prepared in Example 3 of the present invention under different magnetic fields.

[0023] Figure 7 It is the result graph of the magnetic properties of the GeMnSe-based magnetic memristor prepared in Example 3 of the present invention. Among them, Figure 7 (a)is the room-temperature hysteresis loop ( M - H )graph of the GeMnSe magnetic semiconductor thin film; Figure 7 (b)is the curve graph of the magnetization intensity of the GeMnSe magnetic semiconductor thin film varying with temperature ( M - T )graph, and the inset therein is M - T the first-order differential result graph of the curve.

[0024] Figure 8 It is the result diagram of magnetic field regulation of the GeMnSe-based magnetic memristor prepared in Embodiment 3 of the present invention. Among them, Figure 8 (a)is the logarithmic coordinate diagram of the I-V curve of the device under different magnetic field conditions; Figure 8 (b)is the stability diagram of the low resistance state (LRS) and high resistance state (HRS) recorded after applying a voltage of 0.1 V for more than 10 4 s under a magnetic field of 1000 Oe; Figure 8 (c)is the excitatory postsynaptic current (EPSC) diagram of the device under different magnetic field magnitudes under the stimulation of 30 consecutive positive pulses and 30 consecutive negative pulses; Figure 8 (d)is the diagram of the change relationship of the paired-pulse facilitation (PPF) index caused by applying double pulses to the device under different magnetic fields with the time interval between the two pulses.

[0025] In the figure: 10 - top electrode layer; 20 - resistive switching dielectric layer; 30 - substrate layer; 31 - Pt layer; 32 - SiO2 layer. Detailed implementation manners

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0027] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0028] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0029] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more unless otherwise specifically defined.

[0030] In the related art, research on memristors has focused on traditional non-layered metal oxides, and there are few reports on memristive devices based on layered selenides (such as GeSe). The inventor found that the unique layered structure of layered selenides can provide convenient and fast ion transport channels in both in-plane and out-of-plane directions to construct conductive filaments (CFs) formed by metal atoms or vacancy defects, enabling the device to exhibit obvious memristive behavior. Moreover, the GeSe-based memristor can also exhibit various biomimetic synaptic simulation functions, such as long-term potentiation (LTP) and long-term depression (LTD) plasticity. However, there is no report on the external magnetic field manipulation of the resistance and synaptic behavior of GeSe-based memristors at present. For multifunctional memristors, this is necessary for realizing information storage and neuromorphic applications.

[0031] Based on the above considerations, in order to solve the technical problems that the performance of existing memristors needs to be improved and enhanced, the present application provides a memristor based on an Mn-doped GeSe-based magnetic semiconductor thin film, including a substrate layer, a resistive switching dielectric layer, and a top electrode layer arranged in sequence from bottom to top. Among them, the resistive switching dielectric layer is an Mn-doped GeSe-based magnetic semiconductor thin film, and the thickness of the Mn-doped GeSe-based magnetic semiconductor thin film is 100 nm to 700 nm. By using an Mn-doped GeSe-based thin film with strong ferromagnetism as the resistive switching dielectric layer material and introducing the magnetism of the material into the resistance change process of the device, the memristor exhibits typical resistance switching characteristics and biomimetic synaptic characteristics. Moreover, the memristor of the present application exhibits a magnetic field-tunable resistance switching characteristic and biomimetic synaptic plasticity. In particular, a stable non-volatile resistance switching characteristic can be achieved when a magnetic field of 1000 Oe is applied. The memristor of the present application shows great application potential in multifunctional non-volatile memristive devices and neuromorphic electronic devices.

[0032] The technical solution of the present application will be described in detail below.

[0033] As Figure 1As shown in the figure, a memristor structure based on an Mn-doped GeSe-based magnetic semiconductor thin film provided by the present application includes a substrate layer 30, a resistive switching dielectric layer 20, and a top electrode layer 10 arranged in sequence from bottom to top. Among them, the substrate layer 30 includes an Si layer (with a thickness of 500 mm), an SiO2 layer 32 (with a thickness of 100 nm), and a Pt layer 31 (with a thickness of 100 nm) arranged in sequence from bottom to top. Among them, the Pt layer 31 is located between the Mn-doped GeSe-based magnetic semiconductor thin film and the SiO2 layer 32. The resistive switching dielectric layer 20 is an Mn-doped GeSe-based magnetic semiconductor thin film, and the thickness of the Mn-doped GeSe-based magnetic semiconductor thin film is 100 nm to 700 nm. The concentration of Mn in the Mn-doped GeSe-based magnetic semiconductor thin film is 1%. The top electrode layer is Ag, the thickness of the top electrode layer is 10 to 100 nm, and each top electrode is a circular electrode with a diameter of 100 μm.

[0034] On the other hand, the present application also provides a preparation method for a memristor based on an Mn-doped GeSe-based magnetic semiconductor thin film, including: S1: Cut and clean the Si / SiO2 / Pt substrate layer. Use a diamond knife to cut a 4-inch substrate into small pieces of 1 cm * 1 cm for standby, blow dry the surface of the substrate with nitrogen, and store the cleaned substrate in a vacuum glove box for standby.

[0035] S2: Place the sample: Place GeSe powder and MnCl2 powder as growth sources at a certain ratio in the middle position of the corundum plate, then place the corundum plate at the high-temperature zone position in a two-temperature zone tube furnace, and place the Si / SiO2 / Pt substrate layer obtained in step S1 at the low-temperature zone position; the distance between the Si / SiO2 / Pt substrate layer and the growth source powder on the corundum plate is 25 cm. Set the temperatures of the high-temperature zone and the low-temperature zone to 750 °C to 800 °C and 150 °C to 250 °C respectively, and keep warm for a certain time after reaching the temperatures of the high-temperature zone and the low-temperature zone. The entire growth process is carried out in an Ar / H2 mixed atmosphere, and the proportion of Ar in the Ar / H2 mixed atmosphere is 5%, and the gas flow rate is 10 sccm to 50 sccm.

[0036] Preferably, set the temperatures of the high-temperature zone and the low-temperature zone to 770 °C and 200 °C respectively. The growth curve of the high-temperature zone is from 50 °C to 400 °C in 70 minutes, from 400 °C to 770 °C in 60 minutes, and keep warm for 60 minutes to 150 minutes after reaching 770 °C; the growth curve of the low-temperature zone is from 30 °C to 200 °C in 130 minutes, and keep warm for 60 minutes to 150 minutes after reaching 200 °C.

[0037] S3: Grow the thin film: Start the tube furnace, wait for the tube furnace to cool down to room temperature naturally after the growth is completed, and take a sample to obtain a GeMnSe magnetic semiconductor thin film for standby; S4: Growth of the electrode: A top electrode is prepared on the upper surface of the GeMnSe thin film by using the metal hard mask method through radio frequency magnetron sputtering. Here, the metal top electrode is a circular electrode with a diameter of 100 μm. A metal electrode is deposited on the surface of the GeMnSe thin film by radio frequency magnetron sputtering for 10 min, with a thickness of 10 - 100 nm. The sputtering temperature is room temperature. After the metal electrode sputtering is completed, it needs to be rapidly annealed at 400 °C for 120 s in an N2 atmosphere to obtain a magnetic memristor with an Ag / GeMnSe / Pt structure. The sputtering pressure of radio frequency magnetron sputtering is adjusted between 0.7 - 1 Pa, the sputtering power range is 5 - 10 W, the atmosphere is Ar, and the flow rate is adjusted between 20 - 30 sccm.

[0038] The technical solution of the present application will be described in detail below in conjunction with the embodiments.

[0039] Embodiment 1

[0040] Embodiment 1 of the present invention provides a preparation method for a GeMnSe-based magnetic memristor (metal / GeMnSe / Pt) with different metal top electrodes, and the specific steps are as follows: Step S1: Cut and clean the Si / SiO2 / Pt substrate. Use a diamond knife to cut a 4-inch substrate into small pieces of 1 cm * 1 cm for standby, blow dry the surface of the substrate with nitrogen, and store the cleaned substrate in a vacuum glove box for standby.

[0041] Step S2: Place the sample: Place GeSe powder and MnCl2 powder in a certain proportion (where the mass ratio of MnCl2 powder is 70%) at the middle position on a 5 cm * 2.5 cm corundum plate, then place the corundum plate at the center position of the high-temperature zone in a two-temperature zone tube furnace, and place the Si / SiO2 / Pt substrate obtained in Step S1 at the center position of the low-temperature zone, where the distance between the substrate and the growth source powder is 25 cm.

[0042] Step S3: Set the heating curve: Set the temperatures of the high-temperature zone and the low-temperature zone to 770 °C and 200 °C respectively. The growth curve of the high-temperature zone is 50 °C → 400 °C in 70 min, 400 °C → 770 °C in 60 min, and keep the temperature at 770 °C for 90 min, and then the program cools down naturally. The growth curve of the low-temperature zone is 30 °C → 200 °C in 130 min, keep the temperature at 200 °C for 90 min, and then the program cools down naturally. The entire growth process is carried out in an Ar / H2 mixed atmosphere, and the ventilation flow rate is 30 sccm.

[0043] Step S4: Four top electrodes, namely Au, Ag, Cu, and Al, are prepared on the surface of the GeMnSe thin film by using the metal hard mask method through magnetron sputtering. The electrodes are circular electrodes with a diameter of 100 μm, the deposition time is 10 min, the thickness is 10 - 100 nm, the sputtering temperature is room temperature, and after the electrode sputtering is completed, rapid annealing is required at 400 °C for 120 s in an N2 atmosphere. Finally, metal / GeMnSe / Pt magnetic memristors with different metal top electrodes are successfully fabricated.

[0044] Example 2

[0045] This Example 2 provides a preparation method of a magnetic memristor Ag / GeMnSe / Pt with a 100 - nm - thick GeMnSe magnetic semiconductor thin film as the resistive switching dielectric layer. The specific steps are as follows: Step S1: Cut and clean the Si / SiO2 / Pt substrate. Use a diamond knife to cut a 4 - inch substrate into small pieces of 1 cm * 1 cm for standby, blow dry the surface of the substrate with nitrogen, and store the cleaned substrate in a vacuum glove box for standby.

[0046] Step S2: Place the sample: Place the GeSe powder and MnCl2 powder at the middle position on a 5 cm * 2.5 cm corundum plate according to the mass ratio of MnCl2 powder being 70%. Then place the corundum plate at the center position of the high - temperature zone in a two - temperature - zone tube furnace, and place the Si / SiO2 / Pt substrate obtained in Step S1 at the center position of the low - temperature zone. The distance between the substrate and the growth source powder is 25 cm. Adjusting this distance can grow a GeMnSe thin film with a uniform thickness.

[0047] Step S3: Set the heating curve: Set the temperatures of the high - temperature zone and the low - temperature zone to 770 °C and 200 °C respectively. The growth curve of the high - temperature zone is 50 °C → 400 °C in 70 min, 400 °C → 770 °C in 60 min, keep the temperature at 770 °C for 60 min, and then the program cools down naturally. The growth curve of the low - temperature zone is 30 °C → 200 °C in 130 min, keep the temperature at 200 °C for 60 min, and then the program cools down naturally. The whole growth process is carried out in an Ar / H2 mixed atmosphere, and the gas flow rate is 30 sccm. In this step, adjusting the holding time to 60 min can grow a GeMnSe thin film with a thickness of 100 nm.

[0048] Step S4: Use the metal hard mask method to prepare a top Ag electrode on the surface of the GeMnSe thin film by magnetron sputtering. Here, the Ag electrode is a circular electrode with a diameter of 100 μm, the deposition time is 10 min, the thickness is 10 - 100 nm, the sputtering temperature is room temperature. After the Ag electrode sputtering is completed, it needs to be rapidly annealed at 400 °C for 120 s in an N2 atmosphere. Finally, the Ag / GeMnSe / Pt magnetic memristor is successfully fabricated.

[0049] Example 3

[0050] This Example 3 provides a method for fabricating a magnetic memristor Ag / GeMnSe / Pt with a 300 - nm - thick GeMnSe magnetic semiconductor thin film as the resistive switching dielectric layer. The specific steps are as follows: Step S1: Cut and clean the Si / SiO2 / Pt substrate. Use a diamond knife to cut a 4 - inch substrate into small pieces of 1 cm * 1 cm for standby. Blow dry the surface of the substrate with nitrogen, and store the cleaned substrate in a vacuum glove box for standby.

[0051] Step S2: Place the samples: Place the GeSe powder and MnCl2 powder at the middle position on a 5 cm * 2.5 cm corundum wafer according to the mass ratio of MnCl2 powder being 70%. Then place the corundum wafer at the center position of the high - temperature zone in a two - temperature - zone tube furnace, and place the Si / SiO2 / Pt substrate obtained in Step S2 at the center position of the low - temperature zone, where the distance between the substrate and the growth source powder is 25 cm.

[0052] Step S3: Set the heating curve: Set the temperatures of the high - temperature zone and the low - temperature zone to 770 °C and 200 °C respectively. The growth curve of the high - temperature zone is 50 °C → 400 °C in 70 min, 400 °C → 770 °C in 60 min, keep the temperature at 770 °C for 90 min, and then the program cools down naturally. The growth curve of the low - temperature zone is 30 °C → 200 °C in 130 min, keep the temperature at 200 °C for 90 min, and then the program cools down naturally. The whole growth process is carried out in an Ar / H2 mixed atmosphere, and the gas flow rate is 30 sccm. In this step, by adjusting the holding time of 90 min, a GeMnSe thin film with a thickness of 300 nm can be grown.

[0053] Step S4: Use the metal hard mask method to prepare a top Ag electrode on the surface of the GeMnSe thin film by magnetron sputtering. Here, the Ag electrode is a circular electrode with a diameter of 100 μm, the deposition time is 10 min, the thickness is 10 - 100 nm, the sputtering temperature is room temperature. After the Ag electrode sputtering is completed, it needs to be rapidly annealed at 400 °C for 120 s in an N2 atmosphere. Finally, the Ag / GeMnSe / Pt magnetic memristor is successfully fabricated.

[0054] Example 4

[0055] Example 4 provides a method for preparing a magnetic memristor Ag / GeMnSe / Pt with a 500-nm-thick GeMnSe magnetic semiconductor thin film as a resistive switching dielectric layer. The specific steps are as follows: Step S1: Cut and clean the Si / SiO2 / Pt substrate. Use a diamond knife to cut a 4-inch substrate into small pieces of 1 cm * 1 cm for standby. Blow dry the surface of the substrate with nitrogen, and store the cleaned substrate in a vacuum glove box for standby.

[0056] Step S2: Place the samples: Place GeSe powder and MnCl2 powder at the middle position on a 5 cm * 2.5 cm corundum wafer according to the mass ratio of MnCl2 powder being 70%. Then place the corundum wafer at the center position of the high-temperature zone in a two-temperature-zone tube furnace, and place the Si / SiO2 / Pt substrate obtained in Step S2 at the center position of the low-temperature zone, where the distance between the substrate and the growth source powder is 25 cm.

[0057] Step S3: Set the heating curve: Set the temperatures of the high-temperature zone and the low-temperature zone to 770 °C and 200 °C respectively. The growth curve of the high-temperature zone is 50 °C → 400 °C in 70 min, 400 °C → 770 °C in 60 min, hold at 770 °C for 120 min, and then cool down naturally by the program. The growth curve of the low-temperature zone is 30 °C → 200 °C in 130 min, hold at 200 °C for 120 min, and then cool down naturally by the program. The entire growth process is carried out in an Ar / H2 mixed atmosphere, and the gas flow rate is 30 sccm. In this step, adjusting the holding time to 120 min can grow a GeMnSe thin film with a thickness of 500 nm.

[0058] Step S4: Use the metal hard mask method to prepare a top electrode of Ag on the surface of the GeMnSe thin film by magnetron sputtering. The Ag electrode here is a circular electrode with a diameter of 100 μm, the deposition time is 10 min, the thickness is 10 - 100 nm, the sputtering temperature is room temperature, and after the Ag electrode sputtering is completed, it needs to be rapidly annealed at 400 °C for 120 s in an N2 atmosphere. Finally, the Ag / GeMnSe / Pt magnetic memristor is successfully prepared.

[0059] Example 5

[0060] This example provides a method for preparing a magnetic memristor Ag / GeMnSe / Pt with a 700-nm-thick GeMnSe magnetic semiconductor thin film as a resistive switching dielectric layer. The specific steps are as follows: Step S1: Cut and clean the Si / SiO2 / Pt substrate. Use a diamond knife to cut a 4-inch substrate into small pieces of 1 cm * 1 cm for standby. Blow dry the surface of the substrate with nitrogen, and store the cleaned substrate in a vacuum glove box for standby.

[0061] Step S2: Place the sample: Place GeSe powder and MnCl2 powder at the middle position on a 5 cm * 2.5 cm corundum plate according to the mass ratio of MnCl2 powder being 70%. Then place the corundum plate at the center position of the high-temperature zone in a two-temperature-zone tube furnace, and place the Si / SiO2 / Pt substrate obtained in Step S2 at the center position of the low-temperature zone, where the distance between the substrate and the growth source powder is 25 cm.

[0062] Step S3: Set the heating curve: Set the temperatures of the high-temperature zone and the low-temperature zone to 770 °C and 200 °C respectively. The growth curve of the high-temperature zone is from 50 °C to 400 °C in 70 min, from 400 °C to 770 °C in 60 min, keep the temperature at 770 °C for 150 min, and then the program cools down naturally. The growth curve of the low-temperature zone is from 30 °C to 200 °C in 130 min, keep the temperature at 200 °C for 150 min, and then the program cools down naturally. The whole growth process is carried out in an Ar / H2 mixed atmosphere, and the gas flow rate is 30 sccm. In this step, adjusting the holding time to 150 min can grow a GeMnSe thin film with a thickness of 700 nm.

[0063] Step S4: Use the metal hard mask method to prepare a top electrode of Ag on the surface of the GeMnSe thin film by magnetron sputtering. The Ag electrode here is a circular electrode with a diameter of 100 μm, the deposition time is 10 min, the thickness is 10 - 100 nm, the sputtering temperature is room temperature, and after the Ag electrode sputtering is completed, it needs to be rapidly annealed at 400 °C for 120 s in an N2 atmosphere. Finally, an Ag / GeMnSe / Pt magnetic memristor is successfully prepared.

[0064] In the steps of Example 2 - Example 6, adjusting the holding time can grow a GeMnSe thin film with a thickness of 300 nm, and the optimal growth time for growing a GeMnSe with a thickness of 300 nm is 90 min.

[0065] Example 6

[0066] This Example 6 studied the influence of the Mn doping concentration in the GeMnSe thin film on the resistive switching performance of the memristor. This Example 6 provides a preparation method of a magnetic memristor Ag / GeMnSe / Pt with a GeMnSe magnetic semiconductor thin film with different Mn doping concentrations as the resistive switching dielectric layer. The specific steps are as follows: Step S1: Cut and clean the Si / SiO2 / Pt substrate. Use a diamond knife to cut a 4-inch substrate into small pieces of 1 cm * 1 cm for standby. Dry the surface of the substrate with nitrogen gas, and store the cleaned substrate in a vacuum glove box for standby.

[0067] Step S2: Place the samples: Place GeSe powder and MnCl2 powder in the middle position on a 5 cm * 2.5 cm corundum plate according to a certain ratio (the mass ratios of MnCl2 powder in the mixed powder are 33%, 50%, 60%, and 70% respectively). Then place the corundum plate at the center position of the high-temperature zone in a two-temperature zone tube furnace, and place the Si / SiO2 / Pt substrate obtained in Step S1 at the center position of the low-temperature zone, where the distance between the substrate and the growth source powder is 25 cm.

[0068] Step S3: Set the heating curve: Set the temperatures of the high-temperature zone and the low-temperature zone to 770 °C and 200 °C respectively. The growth curve of the high-temperature zone is 50 °C → 400 °C in 70 min, 400 °C → 770 °C in 60 min, and keep the temperature at 770 °C for 90 min, then the program cools down naturally. The growth curve of the low-temperature zone is 30 °C → 200 °C in 130 min, keep the temperature at 200 °C for 90 min, and then the program cools down naturally. The whole growth process is carried out in an Ar / H2 mixed atmosphere, and the ventilation flow rate is 30 sccm.

[0069] Step S4: Use the metal hard mask method to prepare a top electrode of Ag on the surface of the GeMnSe thin film by magnetron sputtering. The Ag electrode here is a circular electrode with a diameter of 100 μm, the deposition time is 10 min, the thickness is 10 - 100 nm, the sputtering temperature is room temperature. After the Ag electrode sputtering is completed, it needs to be rapidly annealed at 400 °C for 120 s in an N2 atmosphere. Finally, Ag / GeMnSe / Pt magnetic memristors with four different Mn doping concentrations of 0.4%, 0.6%, 0.8%, and 1.0% are successfully prepared.

[0070] The results are as follows: As Figure 1 described, Figure 1 is a schematic diagram of a metal / GeMnSe / Pt / SiO2 / Si structure memristor.

[0071] As Figure 2 described, Figure 2 (a) is the resistive switching performance (I-V curve of the device) of the memristor when using the CVD method to grow GeMnSe resistive switching dielectric layers with different Mn doping concentrations in Example 6. Obviously, among all the memristors, the memristor with a Mn concentration of 1.0% shows the largest resistance switching ratio (R OFF / R ON, ~10 3 ). Figure 2 (b) shows the resistive switching performance (I-V curves of the device) of memristors with GeMnSe thin films of different thicknesses as the resistive switching dielectric layer in Examples 2 to 5. All GeMnSe thin films with different thicknesses are doped with 1.0% Mn. From Figure 2 (b), it can be seen that the memristor with a 300-nm-thick GeMnSe resistive switching dielectric layer shows the best resistive switching behavior, while the 100-nm-thick GeMnSe layer makes the device in a fully conductive state. From Figure 2 (b), it can be seen that the I-V curves of the device are in the low-resistance state at this time, indicating that the device has been voltage-breakdown. The 700-nm-thick GeMnSe layer makes the device always in the high-resistance state, and there is no transition from high resistance to low resistance. Figure 2 (c) shows the resistive switching performance (I-V curves of the device) of GeMnSe-based magnetic memristors prepared with different top electrode materials in Example 1. From Figure 2 (c), it can be seen that only the Ag / GeMnSe / Pt device shows typical non-volatile resistive switching behavior, and the other three devices all show confusing irregular behaviors. This indicates that the Ag electrode is the best choice for the top electrode because Ag has strong chemical stability, light mass, and high diffusivity, and is easy to form conductive filaments in the memristor.

[0072] Figure 3 is a schematic diagram of the structural characterization of the device. Figure 3 (a) is the I-V logarithmic curve of a typical device Ag / GeMnSe / Pt with a 300-nm-thick GeMnSe layer and a Mn concentration of 1.0% prepared in Example 3. The device shows very obvious non-volatile resistive switching behavior. Figure 3 (b) is a cross-sectional SEM micrograph of the GeMnSe / Pt / Si structure prepared in Example 3, where the thicknesses of the GeMnSe thin film and the Pt electrode layer are 300 nm and 100 nm, respectively. Figure 3 (c) is an atomic force microscope (AFM) image of the GeMnSe thin film on the Pt / Si substrate. It can be seen from the figure that the prepared GeMnSe magnetic semiconductor thin film has good surface flatness, and the surface roughness is 0.985 nm.

[0073] Figure 4 (a-e) are TEM-EDS elemental mapping images of Si, Ge, Mn, Se, and Pt, and it can be seen that the distribution of each element is very uniform. Figure 4 (f) is a HRTEM image of the GeMnSe layer; Figure 4 (g) is Figure 4(f)The IFFT images corresponding to the four regions I-IV in the figure. Both the HRTEM image and the IFFT image here show that the microstructure of the GeMnSe thin film is a polycrystalline structure. Figure 4 (h)The SAED image of the GeMnSe thin film, which also proves that the GeMnSe thin film is a polycrystalline structure. Figure 5 (a)is the EDS spectrum of the GeMnSe thin film, which proves the existence of the Mn doping element. Figure 5 (b)is the XRD spectrum of the GeMnSe thin film. It can be clearly seen from the figure that the thin film has diffraction peaks at 32.1°, 32.9°, and 52.7°, corresponding to the (111), (400), and (511) crystal planes respectively. This corresponds to the JCPDS 48-1226 card of α-GeSe and belongs to the space group of Pnma, with good crystallinity, which also shows that the doping of Mn does not change the crystal structure of GeSe. Figure 5 (c)is the Raman spectrum of the GeMnSe thin film, and two characteristic vibration peaks of GeSe appear in the spectrum.

[0074] Device performance test.

[0075] The electrical properties and synaptic simulation functions of the Ag / GeMnSe / Pt magnetic memristor were tested in magnetic fields of different magnitudes. The schematic diagram of the device test setup is shown later Figure 6 as Figure 6 shown. It is the schematic diagram of the device test setup in the magnetic field, where the direction of the magnetic field is parallel to the surface of the device. When testing the performance of the memristor, the top electrode of the device is contacted with the positive electrode of the probe station, and the Pt bottom electrode is contacted with the negative electrode of the probe station. Enter the software operation page and select the voltage sweep mode for testing. During the scanning process, the scanning voltage is set to -2 V®2 V, and the scanning directions are set to four: 0 V®2 V, 2 V®0 V, 0 V®-2 V, -2 V®0 V. To avoid breakdown of the device due to excessive current during the application of voltage, the current limit (Icc) needs to be set to 100 mA. When testing the brain-like synaptic function, the Keithley 2400 digital source meter is used as the instrument for applying pulse excitation and acquiring response signals to test the device for simulating biological synaptic functions.

[0076] As Figure 7 shown, Figure 7 it is the basic magnetic properties of the resistive switching dielectric layer GeMnSe of the device. Figure 7 (a)is the room-temperature hysteresis loop of the GeMnSe magnetic semiconductor thin film ( M - H ), which shows that the GeMnSe magnetic semiconductor thin film prepared by the present invention has room-temperature ferromagnetism, and the saturation magnetization intensity is 28.3×10-3 emu / cm 3 ; Figure 7 (b) is the curve of the magnetization intensity of the GeMnSe magnetic semiconductor thin film varying with temperature ( M - T ), and the inset in it is M - T the first-order differential result of the curve, from which the Curie temperature of the GeMnSe thin film can be estimated to be 280 K. Figure 8 is the result diagram of magnetic field regulation of the device, Figure 8 (a) is the logarithmic coordinate of the I-V curve of the device under different magnetic field conditions. Obviously, with the increase of the magnetic field, the device shows an offset phenomenon of the SET voltage (Vset) to a higher voltage region, which indicates obvious magnetic field-controlled resistive switching characteristics; Figure 8 (b) is the stability of the LRS and HRS recorded after applying a voltage of 0.1 V for more than 10 4 s under a magnetic field of 1000 Oe, indicating that the device still has relatively good stability under the applied magnetic field condition; Figure 8 (c) is the excitatory synaptic current level in different magnetic field magnitudes under the stimulation of 30 consecutive positive pulses and 30 consecutive negative pulses of the device. Interestingly, the amplitude of the excitatory synaptic current increases with the increase of the magnetic field H, indicating that H helps to enhance and inhibit the synaptic weight in the memristor; Figure 8 (d) is the variation relationship of the double-pulse facilitation index caused by applying double pulses to the device under different magnetic fields with the time interval between the two pulses. Since the magnetic field will cause the movement trajectory of Ag + ions to deviate, resulting in the formation of longer Ag conductive filaments and promoting the current conduction in the GeMnSe layer, the synaptic signals related to the current, such as the excitatory synaptic current level and the double-pulse facilitation index, will be enhanced.

[0077] The electrical property test of this application shows that the device exhibits non-volatile resistive switching storage characteristics, and the magnetic field effectively regulates the resistive switching behavior of the GeMnSe-based memristor. The typical biological synaptic plasticity of the GeMnSe-based memristor is studied through DC and pulse tests, and it is found that the magnetic field also has an obvious regulatory effect on the synaptic plasticity of the GeMnSe-based memristor.

[0078] In summary, the GeMnSe magnetic semiconductor thin-film magnetic memristor prepared by the preparation method used in the present invention exhibits obvious resistance switching characteristics and biological synaptic plasticity, and both of these characteristics can be regulated by a magnetic field. At the same time, the CVD method for preparing the GeMnSe magnetic semiconductor thin film in the present invention has low requirements for equipment, does not require a high-vacuum environment and complex reactants to participate, and can react in an Ar / H2 mixed atmosphere under a general-level vacuum degree. The magnetron sputtering method for preparing the memristor electrode is also a very general method of use, thus greatly reducing the experimental cost and being simple and easy to implement, and having broad application prospects in the preparation of multifunctional non-volatile memristive devices and neuromorphic electronic devices.

[0079] The foregoing are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A memristor based on an Mn-doped GeSe-based magnetic semiconductor thin film, characterized in that It includes a substrate layer (30), a resistive switching dielectric layer (20), and a top electrode layer (10) arranged successively from bottom to top. Among them, the resistive switching dielectric layer (20) is a Mn-doped GeSe-based magnetic semiconductor thin film, and the thickness of the Mn-doped GeSe-based magnetic semiconductor thin film is 100 nm to 700 nm.

2. The memristor according to claim 1, wherein The concentration of Mn in the Mn-doped GeSe-based magnetic semiconductor thin film is 1%.

3. The memristor according to claim 1, characterized in that, The top electrode layer (10) is Ag, the thickness of the top electrode layer (10) is 10 to 100 nm, and each top electrode is a circular electrode with a diameter of 100 μm.

4. The memristor according to claim 1, characterized in that, The substrate layer (30) includes an Si layer, an SiO2 layer (32), and a Pt layer (31) arranged successively from bottom to top. Among them, the Pt layer (31) is located between the Mn-doped GeSe-based magnetic semiconductor thin film and the SiO2 layer (32).

5. A preparation method of a memristor based on an Mn-doped GeSe-based magnetic semiconductor thin film, characterized in that, It includes: S1: Cut and clean the Si / SiO2 / Pt substrate layer; S2: Place the sample: Place GeSe powder and MnCl2 powder as growth sources in the middle of a corundum wafer, then place the corundum wafer in the high-temperature zone of a two-temperature-zone tube furnace, and place the Si / SiO2 / Pt substrate layer obtained in step S1 in the low-temperature zone; Set the temperatures of the high-temperature zone and the low-temperature zone to 750 °C to 800 °C and 150 °C to 250 °C respectively, and keep the temperature after reaching the temperatures of the high-temperature zone and the low-temperature zone. The whole growth process is carried out in an Ar / H2 mixed atmosphere; S3: Grow the thin film: Start the tube furnace, and wait until the tube furnace cools down to room temperature naturally after the growth ends, and take a sample to obtain a GeMnSe magnetic semiconductor thin film for standby; S4: Grow the electrode: Use the metal hard mask method to prepare a top electrode on the upper surface of the GeMnSe thin film by radio frequency magnetron sputtering. The sputtering temperature is room temperature. After the top electrode sputtering is completed, rapid annealing is carried out in an N2 atmosphere to obtain a magnetic memristor with an Ag / GeMnSe / Pt structure.

6. The preparation method according to claim 5, characterized in that, In step S2, the distance between the Si / SiO2 / Pt substrate layer and the growth source powder on the corundum wafer is 25 cm.

7. The preparation method according to claim 5, characterized in that, In step S2, the temperatures of the high-temperature zone and the low-temperature zone are set to 770 °C and 200 °C respectively, The growth curve of the high-temperature zone is from 50 °C to 400 °C for 70 min, from 400 °C to 770 °C for 60 min, and keep the temperature for 60 min to 150 min after reaching 770 °C; The growth curve of the low-temperature zone is from 30 °C to 200 °C for 130 min, and keep the temperature for 60 min to 150 min after reaching 200 °C.

8. The preparation method according to claim 5, characterized in that, The proportion of Ar in the Ar / H2 mixed atmosphere is 5%, and the gas flow rate is 10 sccm to 50 sccm.

9. The preparation method according to claim 5, wherein In step S4, when growing the electrode, the deposition time is 10 min, the rapid annealing temperature is 400 °C, and the time is 120 s.

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