Mn-doped GeSe-based magnetic semiconductor thin film-based memristor and preparation method thereof

Abstract

The application provides a Mn-doped GeSe-based magnetic semiconductor thin film-based memristor and a preparation method, relates to the technical field of memristors, and comprises, from bottom to top, a substrate layer, a resistance change medium layer and a top electrode layer, wherein the resistance change medium layer 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. The memristor of the application takes the Mn-doped GeSe-based thin film with strong ferromagnetism as the resistance change medium layer material, introduces the magnetism of the material into the resistance change process of the device, so that the memristor exhibits typical resistance transition characteristics and biological synapse characteristics, and the memristor of the application exhibits magnetic field-adjustable resistance transition characteristics and biological synapse plasticity, and shows great application potential in multifunctional nonvolatile memristor devices and neuromorphic electronic devices.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of memristors, in particular to a Mn-doped GeSe-based magnetic semiconductor thin film-based memristor and a preparation method thereof. BACKGROUND

[0002] A memristor is a circuit device that links magnetic flux and charge. A memristor-based resistive random memory device is expected to be used in a new generation of nonvolatile memory devices due to its low energy consumption, high-speed operation and high storage density.

[0003] Existing research on the medium layer of the memristor mainly focuses on traditional non-layered metal oxides, and the performance of the prepared memristor still needs to be improved and improved, therefore, finding new materials suitable for the memristor and preparing a new type of memristor are problems that need to be solved by those skilled in the art. SUMMARY

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

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the application is:

[0006] In a first aspect, the application provides a Mn-doped GeSe-based magnetic semiconductor thin film-based memristor, which comprises a substrate layer, a resistive change medium layer and a top electrode layer arranged in sequence from bottom to top, wherein the resistive change medium layer 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.

[0007] In one or more embodiments of the application, the concentration of Mn in the Mn-doped GeSe-based magnetic semiconductor thin film is 1%.

[0008] In one or more embodiments of the application, the top electrode layer is Ag, and 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 mu m.

[0009] In one or more embodiments of the application, the substrate layer comprises a Si layer, a 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.

[0010] In a second aspect, the application further provides a preparation method of a Mn-doped GeSe-based magnetic semiconductor thin film-based memristor, comprising:

[0011] S1: cutting and cleaning the Si / SiO2 / Pt substrate layer;

[0012] S2: placing the sample: placing GeSe powder and MnCl2 powder as growth sources in the middle position of the corundum sheet in a certain proportion, then placing the corundum sheet in the high-temperature zone position in the double-temperature-zone tube furnace, and placing the Si / SiO2 / Pt substrate layer obtained in step S1 in the low-temperature zone position; setting the temperature of the high-temperature zone and the low-temperature zone to 750 ℃-800 ℃ and 150 ℃-250 ℃ respectively, and maintaining the temperature of the high-temperature zone and the low-temperature zone for a certain time after reaching the temperature of the high-temperature zone and the low-temperature zone, and the whole growth process is carried out in an Ar / H2 mixed atmosphere;

[0013] S3: growing the thin film: starting the tube furnace, and taking the sample to obtain the GeMnSe magnetic semiconductor thin film for standby after the tube furnace naturally cools to room temperature;

[0014] S4: growing the electrode: using a metal hard mask method to prepare a top electrode on the upper surface of the GeMnSe thin film by a radio frequency magnetron sputtering method, the sputtering temperature is room temperature, and after the sputtering of the top electrode is completed, rapid annealing is carried out in an N2 atmosphere to obtain a magnetic memristor with an Ag / GeMnSe / Pt structure.

[0015] 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.

[0016] In one or more embodiments of the present application, in step S2, the temperature of the high-temperature zone and the low-temperature zone is set to 770 ℃ and 200 ℃ respectively,

[0017] The growth curve of the high-temperature zone is 70 min from 50 ℃ to 400 ℃, 60 min from 400 ℃ to 770 ℃, and the temperature is maintained for 60 min-150 min after reaching 770 ℃; the growth curve of the low-temperature zone is 130 min from 30 ℃ to 200 ℃, and the temperature is maintained for 60 min-150 min after reaching 200 ℃.

[0018] In one or more embodiments of the present application, the proportion of Ar in the Ar / H2 mixed atmosphere is 5%, and the gas flow is 10 sccm-50 sccm.

[0019] In one or more embodiments of the present application, in step S4, during the growth of the electrode, the deposition time is 10 min, the rapid annealing temperature is 400 ℃, and the time is 120 s.

[0020] Based on the above technical solution, the magnetic memristor based on the Mn-doped GeSe-based magnetic semiconductor thin film and the preparation method have at least the following beneficial technical effects:

[0021] The Mn-doped GeSe-based magnetic semiconductor thin film of the present application is used as a resistance change medium layer material, and the magnetism of the material is introduced into the resistance change process of the device, so that the memristor exhibits typical resistance transition characteristics and biological synapse characteristics. 6 The memristor of the present application exhibits magnetic field adjustable resistance transition characteristics and biological synapse plasticity, especially when a magnetic field of 1000 Oe is applied, stable non-volatile resistance transition characteristics can be achieved, with a high resistance switching ratio (R OFF / R ON ) of 10 4 s, which is due to the driving migration of Ag atoms in the electric field and magnetic field. The memristor of the present application shows great application potential in multifunctional non-volatile memristor devices and neuromorphic electronic devices.

[0022] On the other hand, the present application is based on the preparation method of the Mn-doped GeSe-based magnetic semiconductor thin film memristor, which uses the Mn-doped GeSe thin film with strong ferromagnetism as the resistance change medium layer material, and uses the chemical vapor deposition method and the magnetron sputtering method to prepare the Ag / GeMnSe / Pt structure memristor. The preparation method has low requirements for equipment, does not require high vacuum environment and complex reactants, and can react in Ar / H2 mixed atmosphere under general vacuum degree, which can greatly reduce the preparation cost, and the method is simple and easy to operate, and has broad application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0024] Figure 1 is a structure schematic diagram of the GeMnSe magnetic memristor prepared in embodiments 1 to 6 of the present application.

[0025] Figure 2 is a resistance change performance diagram of the memristor prepared in embodiments 1 to 6 of the present application; wherein, Figure 2 (a) is a resistance change performance diagram of the memristor with different Mn doping concentrations of the GeMnSe resistance change medium layer in embodiment 6 of the present application; Figure 2 (b) is a resistance change performance diagram of the memristor with different thicknesses of the GeMnSe layer as the resistance change medium layer prepared in embodiments 2 to 5; Figure 2(c) is the resistive switching performance plot of GeMnSe magnetic memristor with different top electrode materials prepared in Example 1.

[0026] Figure 3 is a schematic diagram of structural characterization of GeMnSe magnetic memristor, wherein, Figure 3 (a) is the I-V logarithmic curve plot of the device Ag / GeMnSe / Pt prepared in Example 3; Figure 3 (b) is a cross-sectional SEM micrograph of the GeMnSe / Pt / Si structure of Example 3; Figure 3 (c) is an atomic force microscope (AFM) image of the GeMnSe thin film on the Pt / Si substrate.

[0027] Figure 4 is a schematic diagram of structural characterization of GeMnSe magnetic memristor, wherein, Figure 4 (a-e) are TEM-EDS element mapping images of Si, Ge, Mn, Se and Pt; Figure 4 (f) is an HRTEM image of the GeMnSe layer; Figure 4 (g) is Figure 4 the I-IV four regions in (f) corresponding IFFT images; Figure 4 (h) is a SAED image of the GeMnSe thin film.

[0028] Figure 5 is a schematic diagram of structural characterization of GeMnSe magnetic memristor, wherein, Figure 5 (a) is an EDS spectrum in the GeMnSe layer; Figure 5 (b) is an XRD spectrum of the GeMnSe thin film; Figure 5 (c) is a Raman spectrum of the GeMnSe thin film.

[0029] Figure 6 is a schematic diagram of the device for I-V test of the GeMnSe-based magnetic memristor prepared in Example 3 of the present application under different magnetic fields.

[0030] Figure 7 is a result plot of the magnetic properties of the GeMnSe-based magnetic memristor prepared in Example 3 of the present application, wherein, Figure 7 (a) is a room temperature magnetic hysteresis loop (M-H) plot of the GeMnSe magnetic semiconductor thin film; M - H ) plot; Figure 7 (b) is a plot of the magnetization intensity of the GeMnSe magnetic semiconductor thin film changing with temperature (M-T) M - T ) plot, and the inset is M - T the first derivative result plot of the curve.

[0031] Figure 8 Figure 6 is a result graph of magnetic field regulation of GeMnSe-based magnetic memristor prepared in Example 3 of the present application, wherein, Figure 8 (a) is a log coordinate graph of I-V curves of the device under different magnetic field conditions; Figure 8 (b) is a stability graph of low resistance state (LRS) and high resistance state (HRS) recorded after applying 0.1 V voltage for more than 10 4 s under a magnetic field of 1000 Oe; Figure 8 (c) is a graph of excitatory postsynaptic current (EPSC) of the device under different magnetic field sizes after 30 continuous positive pulses and 30 continuous negative pulses; Figure 8 (d) is a graph of the change of double-pulse facilitation (PPF) index of the device under different magnetic fields after applying double pulses.

[0032] In the figure: 10 - top electrode layer; 20 - resistive switching medium layer; 30 - substrate layer; 31 - Pt layer; 32 - SiO2 layer. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application.

[0034] 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.

[0035] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0036] In addition, the terms "first", "second", "third", etc. are only used for description purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0037] In the related art, research on memristors is focused on traditional non-layered metal oxides, and there are few reports on layered selenide (such as GeSe) memristors. The inventors have found that the unique layered structure of layered selenide can provide convenient and fast ion transmission channels in the in-plane and out-of-plane directions to construct conductive filaments (CF) formed by metal atoms or vacancy defects, so that the device exhibits obvious memristive behavior. Moreover, the GeSe-based memristor can also exhibit a variety of biomimetic synaptic simulation functions, such as long-term potentiation (LTP) and long-term depression (LTD) plasticity. However, there is currently no report on the external magnetic field manipulation of the resistance and synaptic behavior of the GeSe-based memristor, which is necessary for multifunctional memristors to achieve information storage and neuromorphic applications.

[0038] Based on the above considerations, in order to solve the technical problems that the performance of the existing memristor needs to be improved and improved, the present application provides a Mn-doped GeSe-based magnetic semiconductor thin film-based memristor, which comprises a substrate layer, a resistance change medium layer and a top electrode layer arranged in turn from bottom to top, wherein the resistance change medium layer is a Mn-doped GeSe-based magnetic semiconductor thin film, and the thickness of the Mn-doped GeSe-based magnetic semiconductor thin film is 100-700 nm. By using a Mn-doped GeSe-based thin film with strong ferromagnetism as the resistance change medium layer material, the magnetic properties of the material are introduced into the resistance change process of the device, so that the memristor exhibits typical resistance transition characteristics and biological synaptic characteristics, and the memristor of the present application exhibits magnetic field adjustable resistance transition characteristics and biological synaptic plasticity, especially when a magnetic field of 1000 Oe is applied, stable non-volatile resistance transition characteristics can be achieved. The memristor of the present application shows great application potential in multifunctional non-volatile memristor devices and neuromorphic electronic devices.

[0039] The technical solutions of the present application will be described in detail below.

[0040] As Figure 1As shown, the application provides a Mn-doped GeSe-based magnetic semiconductor thin film-based memristor structure, which comprises, from bottom to top, a substrate layer 30, a resistance change medium layer 20 and a top electrode layer 10. The substrate layer 30 comprises, from bottom to top, a Si layer (500 mm in thickness), a SiO2 layer 32 (100 nm in thickness) and a Pt layer 31 (100 nm in thickness). The Pt layer 31 is located between the Mn-doped GeSe-based magnetic semiconductor thin film and the SiO2 layer 32. The resistance change medium layer 20 is a Mn-doped GeSe-based magnetic semiconductor thin film. 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, and the thickness of the top electrode layer is 10 nm to 100 nm. Each top electrode is a circular electrode with a diameter of 100 μm.

[0041] In another aspect, the application also provides a preparation method of a Mn-doped GeSe-based magnetic semiconductor thin film-based memristor, which comprises:

[0042] S1: cutting and cleaning a Si / SiO2 / Pt substrate layer. A 4-inch substrate is cut into small pieces of 1 cm*1 cm using a diamond knife, the surface of the substrate is blown dry with nitrogen, and the cleaned substrate is stored in a vacuum glove box for standby.

[0043] S2: placing the sample: GeSe powder and MnCl2 powder are placed as growth sources in the middle position of a corundum piece in a certain proportion, then the corundum piece is placed in the high-temperature zone position of a double-zone tube furnace, and the Si / SiO2 / Pt substrate layer obtained in step S1 is placed in the low-temperature zone position; the distance between the Si / SiO2 / Pt substrate layer and the growth source powder on the corundum piece is 25 cm, the temperatures of the high-temperature zone and the low-temperature zone are set to 750 ℃ to 800 ℃ and 150 ℃ to 250 ℃ respectively, and a certain time is kept after the temperatures of the high-temperature zone and the low-temperature zone are reached. The whole growth process is carried out in an Ar / H2 mixed atmosphere, the proportion of Ar in the Ar / H2 mixed atmosphere is 5%, and the gas flow is 10 sccm to 50 sccm.

[0044] Preferably, the temperatures of the high-temperature zone and the low-temperature zone are set to 770 ℃ and 200 ℃ respectively, the growth curve of the high-temperature zone is 70 min from 50 ℃ to 400 ℃, 60 min from 400 ℃ to 770 ℃, and 60 min to 150 min after reaching 770 ℃; the growth curve of the low-temperature zone is 130 min from 30 ℃ to 200 ℃, and 60 min to 150 min after reaching 200 ℃.

[0045] S3: Growth of thin film: start the tube furnace, and wait until the growth is completed and the tube furnace is naturally cooled to room temperature. Sample the GeMnSe magnetic semiconductor thin film to obtain a GeMnSe magnetic semiconductor thin film for standby;

[0046] S4: Growth of electrode: a metal hard mask method is used to prepare a top electrode on the upper surface of the GeMnSe thin film by a radio frequency magnetron sputtering method. The metal top electrode here is a circular electrode with a diameter of 100 μm. The metal electrode is deposited on the surface of the GeMnSe thin film by radio frequency magnetron sputtering for 10 min, and the thickness is 10-100 nm. The sputtering temperature is room temperature. After the metal electrode sputtering is completed, rapid annealing is required at 400 ℃ under N2 atmosphere for 120 s to obtain a magnetic memristor with Ag / GeMnSe / Pt structure. The sputtering pressure of the radio frequency magnetron sputtering is adjusted between 0.7-1 Pa, the sputtering power is adjusted between 5-10 W, the atmosphere is Ar, and the flow rate is adjusted between 20-30 sccm.

[0047] The technical solutions of the present application will be described in detail below in conjunction with the embodiments.

[0048] Embodiment 1

[0049] This embodiment 1 provides a preparation method of a GeMnSe-based magnetic memristor (metal / GeMnSe / Pt) with different metal top electrodes, and the specific steps are as follows:

[0050] Step S1: Cut and clean the Si / SiO2 / Pt substrate. Use a diamond knife to cut a 4-inch substrate into a small piece 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: Sample: place GeSe powder and MnCl2 powder in a certain proportion (wherein the mass ratio of MnCl2 powder is 70%) on the middle position of a 5 cm*2.5 cm corundum piece, and then place the corundum piece in the center position of the high-temperature zone of the double-temperature-zone tube furnace. Place the Si / SiO2 / Pt substrate obtained in step S1 in the center position of the low-temperature zone, wherein the distance between the substrate and the growth source powder is 25 cm.

[0052] Step S3: Set the temperature rising curve: set the temperatures of the high-temperature zone and the low-temperature zone to 770 ℃ and 200 ℃ respectively. The growth curve of the high-temperature zone is 50 ℃→400 ℃ for 70 min, 400 ℃→770 ℃ for 60 min, and 770 ℃ for 90 min. Then, the program is naturally cooled. The growth curve of the low-temperature zone is 30 ℃→200 ℃ for 130 min, and 200 ℃ for 90 min. Then, the program is naturally cooled. The whole growth process is carried out in an Ar / H2 mixed atmosphere, and the flow rate of the air is 30 sccm.

[0053] Step S4: Four kinds of top electrodes, Au, Ag, Cu and Al, were prepared on the surface of the GeMnSe thin film by a metal hard mask method through a magnetron sputtering method, the electrodes were circular electrodes with a diameter of 100 μm, the deposition time was 10 min, the thickness was 10-100 nm, the sputtering temperature was room temperature, and after the electrode sputtering was completed, rapid annealing at 400 ℃ for 120 s was required in a N2 atmosphere. Finally, a metal / GeMnSe / Pt magnetic memristor with different metal top electrodes was successfully prepared.

[0054] Example 2

[0055] This embodiment 2 provides a preparation method of a magnetic memristor Ag / GeMnSe / Pt with a 100 nm thick GeMnSe magnetic semiconductor thin film as a resistive switching medium layer, and the specific steps are as follows:

[0056] Step S1: Cut and clean the Si / SiO2 / Pt substrate, use a diamond knife to cut the 4-inch substrate into 1 cm*1 cm pieces for standby, blow dry the surface of the substrate with nitrogen, and store the cleaned substrate in a vacuum glove box for standby.

[0057] Step S2: Sample: Place GeSe powder and MnCl2 powder on a 5 cm*2.5 cm corundum piece in a ratio of 70% MnCl2 powder by mass in the middle position, then place the corundum piece in the center of the high temperature zone of the double-zone tube furnace, and place the Si / SiO2 / Pt substrate obtained in step S1 in the center of the low temperature zone, wherein the distance between the substrate and the growth source powder is 25 cm, and adjusting this distance can grow a GeMnSe thin film with uniform thickness.

[0058] Step S3: Set the temperature rising curve: set the temperature of the high temperature zone and the low temperature zone to 770 ℃ and 200 ℃ respectively, the growth curve of the high temperature zone is 50 ℃→400 ℃ for 70 min, 400 ℃→770 ℃ for 60 min, and 770 ℃ for 60 min, then the program naturally cools down, the growth curve of the low temperature zone is 30 ℃→200 ℃ for 130 min, 200 ℃ for 60 min, and then the program naturally cools down, the whole growth process is carried out in an Ar / H2 mixed atmosphere, and the flow rate of the gas is 30 sccm. In this step, adjusting the holding time for 60 min can grow a 100 nm thick GeMnSe thin film.

[0059] Step S4: The top electrode of Ag was prepared on the surface of the GeMnSe thin film by a metal hard mask method through a magnetron sputtering method, the Ag electrode here was a circular electrode with a diameter of 100 pm, the deposition time was 10 min, the thickness was 10-100 nm, the sputtering temperature was room temperature, and after the Ag electrode sputtering was completed, rapid annealing at 400 °C for 120 s was required in a N2 atmosphere. Finally, the Ag / GeMnSe / Pt magnetic memristor was successfully prepared.

[0060] Example 3

[0061] This example 3 provides a preparation method of a magnetic memristor Ag / GeMnSe / Pt with a 300 nm thick GeMnSe magnetic semiconductor thin film as a resistive switching medium layer, the specific steps are as follows:

[0062] Step S1: Cut and clean the Si / SiO2 / Pt substrate, use a diamond knife to cut a 4-inch substrate into 1 cm*1 cm pieces for standby, blow dry the surface of the substrate with nitrogen, and store the clean substrate in a vacuum glove box for standby.

[0063] Step S2: Put the sample: Put GeSe powder and MnCl2 powder on the middle position of the 5 cm*2.5 cm corundum piece in a ratio of 70% MnCl2 powder, then put the corundum piece in the center of the high temperature zone of the double temperature zone tube furnace, and put the Si / SiO2 / Pt substrate obtained in step S2 in the center of the low temperature zone, wherein the distance between the substrate and the growth source powder is 25 cm.

[0064] Step S3: Set the temperature rising curve: set the temperature 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 for 70 min, 400 °C→770 °C for 60 min, and 770 °C for 90 min, then the program naturally cools down, the growth curve of the low temperature zone is 30 °C→200 °C for 130 min, 200 °C for 90 min, and then the program naturally cools down, the whole growth process is carried out in an Ar / H2 mixed atmosphere, and the flow rate of the gas is 30 sccm. In this step, adjusting the holding time for 90 min can grow a 300 nm thick GeMnSe thin film.

[0065] Step S4: The top electrode of Ag was prepared on the surface of the GeMnSe thin film by a metal hard mask method through a magnetron sputtering method, the Ag electrode here was a circular electrode with a diameter of 100 pm, the deposition time was 10 min, the thickness was 10-100 nm, the sputtering temperature was room temperature, and after the Ag electrode sputtering was completed, rapid annealing at 400 °C for 120 s was required in a N2 atmosphere. Finally, the Ag / GeMnSe / Pt magnetic memristor was successfully prepared.

[0066] Example 4

[0067] This example 4 provides a preparation method of a magnetic memristor Ag / GeMnSe / Pt with a 500 nm thick GeMnSe magnetic semiconductor thin film as a resistive switching medium layer, the specific steps are as follows:

[0068] Step S1: Cut and clean the Si / SiO2 / Pt substrate, use a diamond knife to cut a 4-inch substrate into 1 cm*1 cm pieces for standby, blow dry the surface of the substrate with nitrogen, and store the clean substrate in a vacuum glove box for standby.

[0069] Step S2: Put the sample: Put GeSe powder and MnCl2 powder on the middle position of the 5 cm*2.5 cm corundum piece in a ratio of 70% MnCl2 powder, then put the corundum piece in the center of the high temperature zone of the double temperature zone tube furnace, and put the Si / SiO2 / Pt substrate obtained in step S2 in the center of the low temperature zone, wherein the distance between the substrate and the growth source powder is 25 cm.

[0070] Step S3: Set the temperature rising curve: set the temperature 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 for 70 min, 400 °C→770 °C for 60 min, 770 °C for 120 min, and then the program naturally cools down, the growth curve of the low temperature zone is 30 °C→200 °C for 130 min, 200 °C for 120 min, and then the program naturally cools down, the whole growth process is carried out in an Ar / H2 mixed atmosphere, and the flow rate of the gas is 30 sccm. In this step, adjusting the holding time for 120 min can grow a 500 nm thick GeMnSe thin film.

[0071] Step S4: The top electrode of Ag was prepared on the surface of the GeMnSe thin film by a metal hard mask method through a magnetron sputtering method, the Ag electrode here was a circular electrode with a diameter of 100 pm, the deposition time was 10 min, the thickness was 10-100 nm, the sputtering temperature was room temperature, and after the Ag electrode sputtering was completed, rapid annealing at 400 DEG C for 120 s was required in a N2 atmosphere. Finally, the Ag / GeMnSe / Pt magnetic memristor was successfully prepared.

[0072] Example 5

[0073] The embodiment provides a preparation method of a magnetic memristor Ag / GeMnSe / Pt with a 700 nm thick GeMnSe magnetic semiconductor thin film as a resistive switching medium layer, and the specific steps are as follows:

[0074] Step S1: Cutting and cleaning the Si / SiO2 / Pt substrate, using a diamond knife to cut the 4-inch substrate into 1 cm*1 cm small pieces for standby, blowing the surface of the substrate dry with nitrogen, and storing the cleaned substrate in a vacuum glove box for standby.

[0075] Step S2: Sample: GeSe powder and MnCl2 powder are placed on the middle position of the 5 cm*2.5 cm corundum piece in a ratio of 70% MnCl2 powder, and then the corundum piece is placed in the center of the high-temperature zone of the double-zone tube furnace, and the Si / SiO2 / Pt substrate obtained in step S2 is placed in the center of the low-temperature zone, wherein the distance between the substrate and the growth source powder is 25 cm.

[0076] Step S3: Set the temperature rising curve: the temperature of the high-temperature zone and the low-temperature zone is set to 770 DEG C and 200 DEG C respectively, the growth curve of the high-temperature zone is 50 DEG C→400 DEG C for 70 min, 400 DEG C→770 DEG C for 60 min, and 770 DEG C for 150 min, and then the program is naturally cooled, the growth curve of the low-temperature zone is 30 DEG C→200 DEG C for 130 min, 200 DEG C for 150 min, and then the program is naturally cooled, and the whole growth process is carried out in an Ar / H2 mixed atmosphere, and the flow rate of the air is 30 sccm. In this step, adjusting the holding time for 150 min can grow a 700 nm thick GeMnSe thin film.

[0077] Step S4: The top electrode of Ag was prepared on the surface of the GeMnSe thin film by a metal hard mask method through a magnetron sputtering method. 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 the Ag electrode needs to be rapidly annealed at 400 ℃ for 120 s in a N2 atmosphere after sputtering. Finally, the Ag / GeMnSe / Pt magnetic memristor is successfully prepared.

[0078] In the steps of Example 2-Example 6, the holding time is adjusted to grow a GeMnSe thin film with a thickness of 300 nm. The optimal growth time for growing a GeMnSe thin film with a thickness of 300 nm is 90 min.

[0079] Example 6

[0080] This Example 6 studies 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 method for preparing a magnetic memristor Ag / GeMnSe / Pt with a GeMnSe magnetic semiconductor thin film with different Mn doping concentrations as a resistive switching medium layer. The specific steps are as follows:

[0081] Step S1: Cut and clean the Si / SiO2 / Pt substrate. Use a diamond knife to cut a 4-inch substrate into 1 cm*1 cm pieces for standby. Blow dry the surface of the substrate with nitrogen, and store the cleaned substrate in a vacuum glove box for standby.

[0082] Step S2: Sample: Place GeSe powder and MnCl2 powder in a certain proportion (the mass ratio of MnCl2 powder in the mixed powder is 33%, 50%, 60% and 70% respectively) on the middle position of a 5 cm*2.5 cm corundum piece, and then place the corundum piece in the center position of the high temperature zone in the double-zone tube furnace. Place the Si / SiO2 / Pt substrate obtained in step S1 in the center position of the low temperature zone, wherein the distance between the substrate and the growth source powder is 25 cm.

[0083] Step S3: Set the temperature rising curve: set the temperature of the high temperature zone and the low temperature zone to 770 ℃ and 200 ℃ respectively. The growth curve of the high temperature zone is 50 ℃→400 ℃ for 70 min, 400 ℃→770 ℃ for 60 min, and 770 ℃ for 90 min. Then the program naturally cools down. The growth curve of the low temperature zone is 30 ℃→200 ℃ for 130 min, and 200 ℃ for 90 min. Then the program naturally cools down. The whole growth process is carried out in an Ar / H2 mixed atmosphere with a flow rate of 30 sccm.

[0084] Step S4: The top electrode of Ag was prepared on the surface of GeMnSe thin film by magnetron sputtering method using metal hard mask method, the Ag electrode here is a circular electrode with a diameter of 100 pm, the deposition time is 10 min, the thickness is 10-100 nm, the sputtering temperature is room temperature, and after the sputtering of Ag electrode is completed, it needs to be rapidly annealed at 400 °C for 120 s in N2 atmosphere, finally the Ag / GeMnSe / Pt magnetic memristor with Mn doping concentration of 0.4%, 0.6%, 0.8% and 1.0% is successfully prepared.

[0085] The results are as follows:

[0086] As Figure 1 mentioned, Figure 1 is a schematic diagram of the metal / GeMnSe / Pt / SiO2 / Si structure memristor.

[0087] As Figure 2 mentioned, Figure 2 (a) is the resistive switching performance (I-V curve of the device) of the memristor when the GeMnSe resistive switching medium layer with different Mn doping concentrations is grown by the CVD method in Example 6, it is obvious that the memristor with Mn concentration of 1.0% shows the largest resistance switching ratio (R OFF / R ON , ~10 3 ). Figure 2 (b) is the resistive switching performance (I-V curve of the device) of the memristor when the GeMnSe thin film with different thicknesses is used as the resistive switching medium layer in Example 2 to Example 5, all the GeMnSe thin films 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 medium layer shows the best resistance transition behavior, while the 100 nm thick GeMnSe layer makes the device in a completely conductive state, from Figure 2 (b) it can be seen that the I-V curve of the device at this time is in a low resistance state, indicating that the device has been voltage breakdown, and the 700 nm thick GeMnSe layer makes the device always in a high resistance state, without transition from high resistance to low resistance. Figure 2 (c) is the resistive switching performance (I-V curve of the device) of the GeMnSe-based magnetic memristor 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 resistance transition behavior, and the other three devices show confusing irregular behavior, which indicates that Ag electrode is the best choice for the top electrode, because Ag has strong chemical stability, light mass and high diffusion rate, and is easy to form conductive filaments in the memristor.

[0088] Figure 3 is a schematic diagram of the structure 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 resistance transition behavior. Figure 3 (b) is a cross-sectional SEM micrograph of a GeMnSe / Pt / Si structure prepared in Example 3, wherein the thickness of the GeMnSe film and the Pt electrode layer is 300 nm and 100 nm, respectively. Figure 3 (c) is an atomic force microscope (AFM) image of a GeMnSe film on a Pt / Si substrate, as can be seen from the figure, the prepared GeMnSe magnetic semiconductor film has good surface flatness, and the surface roughness is 0.985 nm.

[0089] Figure 4 (a-e) are TEM-EDS element mapping images of Si, Ge, Mn, Se and Pt, it can be seen that the distribution of each element is very uniform. Figure 4 (f) is an HRTEM image of the GeMnSe layer; Figure 4 (g) is Figure 4 (f) I-IV four regions corresponding to the IFFT image in the figure, both the HRTEM image and the IFFT image here show that the microstructure of the GeMnSe film is polycrystalline structure. Figure 4 (h) is a SAED image of the GeMnSe film, the SAED image also proves that the GeMnSe film is polycrystalline structure. Figure 5 (a) is an EDS spectrum of the GeMnSe film, which proves the existence of Mn doped elements. Figure 5 (b) is an XRD spectrum of the GeMnSe film, from the figure it can be seen that the film has diffraction peaks at 32.1°, 32.9°, 52.7°, respectively, corresponding to (111), (400) and (511) crystal planes, which corresponds to the JCPDS 48-1226 card of a-GeSe, belonging to the space group Pnma, with good crystallinity, also indicating that the doping of Mn does not change the crystal structure of GeSe. Figure 5 (c) is a Raman spectrum of the GeMnSe film, two characteristic vibration peaks of GeSe appear in the spectrum.

[0090] Device performance test.

[0091] The electrical performance and synaptic simulation function of the Ag / GeMnSe / Pt magnetic memristor were tested in different sizes of magnetic field, and the device test device schematic diagram is shown in the following Figure 6 , Figure 6is a schematic diagram of a device testing device in a magnetic field, wherein 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 in contact with the positive electrode of the probe station, the Pt bottom electrode is in contact with the negative electrode of the probe station, the software operation page is entered, the voltage scanning mode is selected, and the testing is performed. During the scanning process, the scanning voltage is set to -2 V®2 V, and the scanning direction is set to four: 0 V®2 V, 2 V®0 V, 0 V®-2 V, and -2 V®0 V. In order to avoid the device from being broken down due to excessive current during the application of the voltage, it is necessary to set the current limit (Icc) to 100 mA. When testing the brain synapse function, a Keithley 2400 digital source meter is used as a pulse excitation application and response signal acquisition instrument to test the simulated biological synapse function of the device.

[0092] As shown in Figure 7 , Figure 7 is the basic magnetic property of the resistive switching medium 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 application has room temperature ferromagnetism, and the saturation magnetization is 28.3×10 -3 emu / cm 3 ; Figure 7 (b) is the curve of the magnetization of the GeMnSe magnetic semiconductor thin film with temperature M - T , and the insert is the first-order differential result of the curve M - T , from which it can be estimated that the Curie temperature of the GeMnSe thin film is 280 K. Figure 8 is a result graph of magnetic field regulation of the device, Figure 8 (a) is the I-V curve of the device in the logarithmic coordinate under different magnetic field conditions, and it is obvious that with the increase of the magnetic field, the SET voltage (Vset) of the device shows the phenomenon of shifting to a higher voltage region, which indicates the obvious magnetic field controlled resistance switching characteristic; Figure 8 (b) is the stability of 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, which shows that the device still has good stability under the condition of applying a magnetic field; Figure 8 (c) is the excitatory synaptic current level of the device under different magnetic field sizes under the stimulation of 30 continuous positive pulses and 30 continuous negative pulses, and interestingly, the amplitude of the excitatory synaptic current increases with the increase of the magnetic field H, which shows that H helps to enhance and inhibit the weight of the synapse in the memristor; Figure 8(d) is the relationship between the double-pulse facilitation index caused by applying double pulses to the device under different magnetic fields and the time interval between the two pulses. + Due to the shift of the motion trajectory of Ag ions caused by the magnetic field, longer Ag conductive filaments are formed, which promotes the current conduction in the GeMnSe layer, and thus the synaptic signals related to the current, such as the excitatory synaptic current level and the double-pulse facilitation index, are enhanced.

[0093] The electrical performance test of the present application shows that the device exhibits non-volatile resistance change memory characteristics, and the resistance switching behavior of the GeMnSe-based memristor is effectively regulated by using a magnetic field.

[0094] In summary, the GeMnSe magnetic semiconductor thin film magnetic memristor prepared by the preparation method used in the present application exhibits obvious resistance transition characteristics and biological synaptic plasticity, and both of these two characteristics can be regulated by using a magnetic field.

[0095] The above only describes the preferred embodiments of the present application and is not intended to limit the present application, and any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A memristor based on Mn-doped GeSe-based magnetic semiconductor thin film, characterized in that, The memristor comprises a substrate layer (30), a resistive switching dielectric layer (20), and a top electrode layer (10) arranged sequentially from bottom to top. The resistive switching dielectric layer (20) is a Mn-doped GeSe-based magnetic semiconductor thin film with a thickness of 300 nm to 500 nm and a Mn concentration of 1%. The top electrode layer (10) is Ag with a thickness of 10 to 100 nm. Each top electrode is a circular electrode with a diameter of 100 μm. The memristor has magnetic field-controlled resistive switching characteristics and biological synaptic plasticity. With the increase of the magnetic field, the memristor has the characteristic of shifting the SET voltage to a higher voltage and the characteristic of increasing the resistance switching ratio. The method for fabricating the memristor includes: S1: Trim and clean the Si / SiO2 / Pt substrate layer; S2: Sample placement: GeSe powder and MnCl2 powder are placed in the middle of the corundum sheet as the growth source with a mass ratio of 70% for MnCl2 powder. Then, the corundum sheet is placed in the high-temperature zone of the dual-temperature zone tube furnace, and the Si / SiO2 / Pt substrate obtained in step S1 is placed in the low-temperature zone. The distance between the substrate and the growth source powder is 25cm. S3: Thin Film Growth: Start the tube furnace and set the temperatures of the high-temperature zone and the low-temperature zone to 770℃ and 200℃, respectively. The growth curve for the high-temperature zone is 50℃→400℃ in 70 min, 400℃→770℃ in 60 min, holding at 770℃ for 90~120 min, and then allowing the temperature to cool down naturally. The growth curve for the low-temperature zone is 30℃→200℃ in 130 min, holding at 200℃ for 90~120 min, and then allowing the temperature to cool down naturally. The entire growth process is carried out in an Ar / H2 mixed atmosphere with a gas flow rate of 30 sccm. After the growth is completed, the tube furnace is allowed to cool down naturally to room temperature. S4: Growth electrode: An Ag top electrode was prepared on the surface of a GeMnSe thin film by magnetron sputtering using a metal hard mask method. The Ag electrode was a circular electrode with a diameter of 100 μm. The deposition time was 10 min, the thickness was 10~100 nm, and the sputtering temperature was room temperature. After sputtering, the Ag top electrode was rapidly annealed at 400 °C for 120 s in a N2 atmosphere to obtain a magnetic memristor with an Ag / GeMnSe / Pt structure.

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

3. The memristor according to claim 1, characterized in that, The Ar / H2 mixed atmosphere contains 5% Ar and has a gas flow rate of 10 sccm to 50 sccm.

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