Test device and test method for conducting filaments in oxygen-vacancy type resistive switching devices

Abstract

The application provides a testing device and a testing method for a conductive filament in an oxygen vacancy type resistive switching device. The testing device for the conductive filament in the oxygen vacancy type resistive switching device comprises a focused ion beam microscope, which is suitable for cutting a resistive switching device to form a resistive switching device section; an in-situ chip, which is provided with a bearing surface suitable for bearing the resistive switching device; a conductive probe atomic force microscope, which scans the resistive switching device section and determines the position of the conductive filament according to a current distribution; and a transmission electron microscope, which is suitable for observing the position of the conductive filament. Thus, the current distribution result obtained by CAFM testing and the microstructure obtained by TEM testing can be strictly corresponded in the same testing area of the same resistive switching device, so that the resistance value, the current value and the corresponding atomic resolution microcrystal structure of a single conductive filament can be obtained according to the characterization information.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductors, and in particular, to a testing device and a testing method for a conduction filament in an oxygen-vacancy type resistive switching device. BACKGROUND

[0002] Most of the resistive switching devices with metal oxide as the core material, their working mechanism depends on the formation of a conduction filament connecting the upper and lower electrodes inside the resistive switching layer. It is generally believed that under the action of an applied electric field, oxygen ions will be formed inside the resistive switching layer and at the interface between the resistive switching layer and the upper and lower electrodes. These oxygen ions will migrate directionally under the driving of the potential energy of the directional electric field and Joule heat, leaving oxygen vacancies inside the resistive switching layer. The oxygen vacancies gathered together form a conductive channel, connecting the upper and lower electrodes and constituting a conduction filament. Under different loading conditions, the conduction filament will undergo the following evolution: formation in the forming process of the write operation, connection in the setting process of the set operation, and disconnection in the resetting process of the reset operation. The resistance of the resistive switching device in the original state is in the order of G ohms; after the formation of the conduction filament, a conductive channel is established between the upper and lower electrodes through the conduction filament, and the resistance of the device drops to the order of k ohms; after the reset operation, the conduction filament is disconnected, and the resistance of the resistive switching device rises to the order of M ohms. Therefore, the evolution process of the conduction filament causes the resistance of the resistive switching device to change between the high resistance state (M ohms) and the low resistance state (k ohms).

[0003] The way to characterize the conduction filament in the related art is to combine the conductive probe atomic force microscope (CAFM) with the transmission electron microscope (TEM) to perform experimental observation. First, the CAFM is used to scan and locate the conductive area on the plane of the resistive switching layer, and then the focused ion beam microscope (FIB) is used to locate and prepare a TEM sample, which is put into the TEM for characterization to observe the size, crystal morphology, and composition ratio of the conduction filament and other detailed microstructure information. This scheme has two main defects. First, for the characterization of the distribution of oxygen elements in the amorphous resistive switching layer, the TEM observation method is difficult to determine the distribution of the conduction filament. In amorphous materials, the atomic arrangement has the characteristic of long-range disorder, so it will not form a high-resolution atomic image characteristic of crystal structure, and it is difficult to obtain the atomic resolution structure information of amorphous materials. According to the inference of the device size and theoretical calculation, the conduction filament is in the order of nanometers, which is difficult to be observed by TEM. Second, the TEM sample preparation process is complex and time-consuming, and the sample preparation process needs to be performed in a vacuum environment, which is difficult to control and has a high cost.

[0004] The size of the filament should be in the range of 2nm to 5nm; while the thickness of the TEM sample is generally in the range of 20nm to 50nm, the size of the conductive filament is quite different from the size of the TEM sample, and the contrast of the conductive filament that can be shown in the bright field image test of the TEM is very limited. How to improve the characterization contrast of the conductive filament is the key to obtain the morphology details of the conductive filament. Second, the conventional TEM characterization method tests the microstructure in the cross section of the resistive switching device stack, while the CAFM tests the current distribution in the plane of the resistive switching layer. The detection results of the two test methods cannot be strictly corresponding, which limits the practical application value of the microcharacterization results. The present application aims to provide a testing device for conductive filaments in oxygen vacancy type resistive switching devices to solve the above problems. SUMMARY

[0005] The present application aims to at least partially solve one of the technical problems in the related art.

[0006] In one aspect of the present application, a testing device for conductive filaments in oxygen vacancy type resistive switching devices is provided, comprising: a focused ion beam microscope, the focused ion beam microscope is adapted to cut the resistive switching device to form a cross section of the resistive switching device, so that the upper electrode cross section, the resistive switching layer cross section and the lower electrode cross section of the resistive switching device are exposed in the same plane; an in-situ chip, the in-situ chip is formed with a bearing surface adapted to bear the resistive switching device, the bearing surface is provided with a connecting electrode and a test electrode; a conductive probe atomic force microscope, the conductive probe atomic force microscope is provided with a first test cavity adapted to accommodate the in-situ chip, the first test cavity is provided with a test platform, the resistive switching device, the connecting electrode, the test electrode and the test platform are electrically connected, the conductive probe scans the cross section of the resistive switching device and determines the position of the conductive filament according to the current distribution; a transmission electron microscope, the transmission electron microscope is adapted to observe the position of the conductive filament to obtain the microstructure of the conductive filament. Thus, the current distribution result obtained by CAFM test and the microstructure obtained by TEM test can be strictly corresponding in the same test area of the same resistive switching device, so as to obtain the resistance value, the current value and the corresponding atomic resolution microcrystal structure of a single conductive filament according to the characterization information.

[0007] According to some embodiments of the present application, the testing device for conductive filaments in oxygen vacancy type resistive switching devices further comprises: an oxygen isotope carrier gas system, the oxygen isotope carrier gas system comprises a carrier gas source, the carrier gas source is in communication with the first test cavity; an ion mass spectrometer, the ion mass spectrometer labels the distribution area of the oxygen ion according to the position of the oxygen isotope.

[0008] According to some embodiments of the present application, the oxygen isotope carrier gas system further comprises: a flow regulator, the flow regulator is arranged between the carrier gas source and the first test cavity.

[0009] In another aspect of the present application, a method for testing a conductive filament in an oxygen vacancy type resistive switching device is provided, comprising: cutting the resistive switching device to form a cross section of the resistive switching device using a focused ion beam microscope, so that a top electrode cross section, a resistive switching layer cross section and a bottom electrode cross section of the resistive switching device are exposed in the same plane; placing the cut resistive switching device on an in-situ chip and electrically connecting the resistive switching device with a connecting electrode of the in-situ chip, the cross section of the resistive switching device facing a bearing plane of the in-situ chip; placing the in-situ chip on a test platform in a first test cavity of a conductive probe atomic force microscope, electrically connecting the resistive switching device, the connecting electrode, a test electrode of the in-situ chip and the test platform, scanning the cross section of the resistive switching device by a conductive probe and determining the position of the conductive filament according to current distribution; and observing the conductive filament using a transmission electron microscope to obtain a microstructure of the conductive filament. Thus, the method can realize strict correspondence between current distribution obtained by CAFM test and microstructure obtained by TEM test in the same test region of the same resistive switching device, so as to obtain resistance value, current value and corresponding atomic resolution microcrystal structure of a single conductive filament according to characterization information.

[0010] According to some embodiments of the present application, the method for testing a conductive filament in an oxygen vacancy type resistive switching device further comprises: introducing oxygen isotope gas into the first test cavity through an oxygen isotope carrier gas system, and testing distribution of the oxygen isotope in the resistive switching device using an ion mass spectrometer.

[0011] According to some embodiments of the present application, the oxygen isotope gas is introduced into the first test cavity before the resistive switching device occurs resistive switching.

[0012] According to some embodiments of the present application, the oxygen isotope gas is introduced into the first test cavity after the resistive switching device occurs resistive switching.

[0013] According to some embodiments of the present application, the placing the cut resistive switching device on the in-situ chip and connecting the resistive switching device with the connecting electrode of the in-situ chip comprises: forming a Pt component deposition wire between the resistive switching device and the connecting electrode by ion beam deposition.

[0014] According to some embodiments of the present application, after forming the cross section of the resistive switching device using the focused ion beam microscope, the resistive switching device is thinned.

[0015] According to some embodiments of the present application, the thickness of the thinned resistive switching device is not more than 50 nm. BRIEF DESCRIPTION OF DRAWINGS

[0016] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings of which:

[0017] Figure 1 A schematic structural diagram of a carrier gas system, a CAFM and an in-situ chip of one embodiment of the present application is shown;

[0018] Figure 2 A schematic structural diagram of a resistive switching device of one embodiment of the present application is shown;

[0019] Figure 3 A schematic structural diagram of an in-situ chip of one embodiment of the present application is shown;

[0020] Figure 4 A schematic structural diagram of a perspective view of a dashed area in FIG. 1 is shown; Figure 3

[0021] Figure 5 A schematic flow diagram of a testing method of a conductive filament in an oxygen vacancy type resistive switching device of one embodiment of the present application is shown;

[0022] Figure 6 A schematic diagram of a way of introducing an oxygen isotope gas of one embodiment of the present application is shown;

[0023] Figure 7 A schematic diagram of a way of introducing an oxygen isotope gas of another embodiment of the present application is shown;

[0024] Figure 8 A schematic structural diagram of an in-situ chip of embodiment 1 of the present application is shown;

[0025] Figure 9 A magnified scanning electron microscope image of a resistive switching device of embodiment 1 of the present application is shown;

[0026] Figure 10 A current distribution diagram of a CAFM test of embodiment 1 of the present application is shown;

[0027] Figure 11 A conductive filament current distribution diagram of a CAFM test of embodiment 1 of the present application is shown.

[0028] Reference signs:

[0029] 1: in-situ chip; 11: first connection electrode; 12: second connection electrode; 13: first test electrode; 14: second test electrode; 2: conductive probe atomic force microscope; 21: conductive probe; 22: conductive probe height displacement test system; 23: electrical signal test system; 3: resistive switching device; 31: lower electrode; 32: resistive switching layer; 33: upper electrode; 34: conductive filament; 4: oxygen isotope carrier gas system; 41: carrier gas source; 42: flow regulator.​ DETAILED DESCRIPTION

[0030] Embodiments of the present application are described in detail below. The embodiments described below are examples for explaining the present application and are not to be understood as limiting the present application. Unless otherwise noted, technical or conditions not specified in the embodiments are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be obtained commercially.

[0031] In one aspect of the present application, a testing device for a conduction filament 34 in an oxygen vacancy type resistive switching device is provided, referring to Figure 1 The testing device for the conduction filament 34 in the oxygen vacancy type resistive switching device includes a focused ion beam microscope (not shown in the figure), an in-situ chip 1, a conductive probe atomic force microscope 2 and a transmission electron microscope (not shown in the figure).

[0032] The focused ion beam microscope is adapted to cut the resistive switching device 3 to form a cross section of the resistive switching device, for example, referring to Figure 2 The resistive switching device 3 includes a lower electrode 31, a resistive switching layer 32 and an upper electrode 33 stacked in a first direction, the focused ion beam can cut the resistive switching device 3 along the first direction, the first direction can be perpendicular to the surface of the upper electrode 33 away from the resistive switching layer 32, or the cutting direction has a certain angle with the first direction, as long as the upper electrode 33 cross section, the resistive switching layer 32 cross section and the lower electrode 31 cross section of the resistive switching device 3 after cutting are exposed in the same plane.

[0033] Referring to Figure 1 , Figure 3 and Figure 4 The in-situ chip 1 has a bearing surface adapted to bear the resistive switching device 3, and the bearing surface is provided with a connection electrode and a test electrode. Specifically, the connection electrode includes a first connection electrode 11 and a second connection electrode 12, the first connection electrode 11 is connected with the upper electrode 33 of the resistive switching device 3, and the second connection electrode 12 is connected with the lower electrode 31 of the resistive switching device 3. The test electrode also includes a first test electrode 13 and a second test electrode 14, the first test electrode 13 is used for grounding, and the second test electrode 14 is suspended.

[0034] The conductive probe atomic force microscope 2 is provided with a first test cavity suitable for accommodating the in-situ chip 1, and a test platform is arranged in the first test cavity, and the cut resistive switching device 3 is placed on the test platform. Specifically, the cross section of the resistive switching device is oriented in a direction parallel to the test platform, so that the cross sections of the upper electrode 33, the resistive switching layer 32 and the lower electrode 31 are exposed, for example, when the cutting direction is perpendicular to the surfaces of the upper electrode 33 and the resistive switching layer 32, the resistive switching device 3 is rotated by 90° after the cross section of the resistive switching device is exposed after cutting, so that the cross sections of the upper electrode 33, the resistive switching layer 32 and the lower electrode 31 are located in the same plane, and the conductive probe 21 can scan the cross section of the resistive switching device and determine the position of the conductive filament 34 according to the current distribution.

[0035] After the positioning of the conductive filament 34 by the CAFM is completed, the transmission electron microscope is suitable for observing the position of the conductive filament 34 to obtain the microstructure of the conductive filament 34. Specifically, the in-situ chip 1 can be placed in the in-situ sample rod of the TEM for testing, and information including the crystal structure of the conductive filament 34, the microstructure and composition distribution of the inside of the resistive switching layer 32 and the upper and lower interfaces of the resistive switching layer 32 can be obtained.

[0036] The testing device of the conductive filament 34 in the oxygen vacancy type resistive switching device 3 according to the present application adopts the in-situ chip 1 compatible with the requirements of CAFM testing and TEM testing, and the in-situ chip 1 can be used to realize the CAFM testing of the upper electrode 33 or the lower electrode 31 of the resistive switching device 3 grounded. By cutting the resistive switching device 3 to form a cross section of the resistive switching device, the conductive filament 34 is formed in-situ on the cross section of the resistive switching device, and the CAFM can directly test the current distribution on the cross section of the resistive switching device. The microstructure information of the cross section of the resistive switching device, including the crystal structure of the conductive filament 34, the microstructure and composition distribution of the inside of the resistive switching layer 32 and the upper and lower interfaces of the resistive switching layer 32, can be obtained by TEM testing. The current distribution result obtained by CAFM and the microstructure obtained by TEM testing can be strictly corresponding in the same test area of the same resistive switching device 3, so that the resistance value, the current value and the corresponding atomic resolution microcrystal structure of a single conductive filament 34 can be obtained according to the characterization information.

[0037] According to some embodiments of the present application, reference is made to Figure 1The testing device of the conductive filament 34 in the oxygen vacancy type resistance switching device 3 can further comprise an oxygen isotope carrier gas system 4 and an ion mass spectrometer (not shown in the figure), the oxygen isotope carrier gas system 4 comprising a carrier gas source 41 in communication with the first testing cavity to introduce oxygen isotope gas into the first testing cavity, and the ion mass spectrometer marking the distribution area of oxygen ions according to the position of oxygen isotopes. In this way, by marking the distribution of oxygen isotopes inside and around the conductive filament 34, the diffusion path of oxygen ions in the formation process of the conductive filament 34 is analyzed, and the connection position and the breaking position of the conductive filament 34 and the quantitative response of the current transport characteristics of the resistance switching device 3 are determined. By adding the oxygen isotope carrier gas system 4 and the ion mass spectrometer, the micro resistance switching mechanism of the resistance switching device 3 can be determined, and by using simulation calculation, the number and movement range of oxygen ions diffusing under the action of electric field potential energy to overcome the migration barrier are further analyzed, thereby providing experimental basis for controlling the migration path of oxygen ions and optimizing process conditions. At the same time, by combining the operation conditions and the evolution process of the internal structure of the conductive filament 34, the regulation and control mechanism of the operation conditions on the conductive filament 34 can be analyzed, thereby providing a reference for optimizing the operation conditions.

[0038] According to some embodiments of the present application, reference is made to Figure 1 The oxygen isotope carrier gas system 4 further comprises a flow regulator 42 arranged between the carrier gas source 41 and the first testing cavity. In this way, the time and the amount of oxygen isotope gas introduced into the first testing cavity can be controlled.

[0039] In another aspect of the present application, a testing method of a conductive filament 34 in an oxygen vacancy type resistance switching device 3 is provided, comprising: cutting the resistance switching device 3 by a focused ion beam microscope to form a resistance switching device cross section, so that the upper electrode 33 cross section, the resistance switching layer 32 cross section and the lower electrode 31 cross section of the resistance switching device 3 are exposed in the same plane; placing the cut resistance switching device 3 on the in-situ chip 1 and electrically connecting the resistance switching device 3 with the connecting electrode of the in-situ chip 1, and the resistance switching device cross section faces the bearing plane of the in-situ chip 1; placing the in-situ chip 1 on the testing platform in the first testing cavity of the conductive probe atomic force microscope 2, and electrically connecting the resistance switching device 3, the connecting electrode, the testing electrode of the in-situ chip 1 and the testing platform, scanning the resistance switching device cross section by the conductive probe 21 and determining the position of the conductive filament 34 according to the current distribution; and observing the conductive filament 34 by a transmission electron microscope to obtain the microstructure of the conductive filament 34.

[0040] The application relates to a testing device for a conductive filament 34 in an oxygen vacancy type resistance change device 3, which adopts an in-situ chip 1 compatible with CAFM testing and TEM testing requirements. The in-situ chip 1 can be used to realize CAFM testing of the upper electrode 33 or the lower electrode 31 of the resistance change device 3 grounded. The resistance change device 3 is cut to form a resistance change device section, and the conductive filament 34 is formed in-situ on the resistance change device section. CAFM can directly test the current distribution on the section of the resistance change device laminated structure, and TEM can test the microstructure information of the resistance change device section, including the crystal structure of the conductive filament 34, the microstructure and component distribution at the upper and lower interfaces of the resistance change layer 32 and inside the resistance change layer 32. The current distribution result obtained by CAFM and the microstructure obtained by TEM can strictly correspond to the same test area of the same resistance change device 3, so that the resistance value and current value of a single conductive filament 34 and the corresponding atomic resolution microcrystal structure can be obtained according to the characterization information.

[0041] The following will be described in detail the steps of the testing method of the conductive filament 34 in the oxygen vacancy type resistance change device 3, referring to Figure 5 The method comprises the following steps.

[0042] S100: preparing a sample to be tested by a focused ion beam microscope

[0043] In this step, the resistance change device 3 is cut by the focused ion beam microscope to form a resistance change device section, so that the upper electrode 33 section, the resistance change layer 32 section and the lower electrode 31 section of the resistance change device 3 are exposed in the same plane; the cut resistance change device 3 is placed on the in-situ chip 1 and electrically connected with the connecting electrodes of the in-situ chip 1, and the resistance change device section faces the bearing plane parallel to the in-situ chip 1.

[0044] Specifically, referring to Figure 4 The first connecting electrode 11 and the second connecting electrode 12 are arranged on the in-situ chip 1, and Pt can be deposited between the upper electrode 33 and the first connecting electrode 11 and between the lower electrode 31 and the second connecting electrode 12 by ion beam deposition to form wires to realize electrical connection.

[0045] According to some specific embodiments of the application, after the resistance change device section is formed by the focused ion beam microscope, the resistance change device 3 can be further thinned. Specifically, the thickness of the thinned resistance change device 3 is not greater than 50 nm, so as to further improve the resolution of the transmission electron microscope characterization result.

[0046] According to some specific embodiments of the application, the size of the in-situ chip 1 can be a chip with a length of 4 mm, a width of 5.8 mm and a thickness of 300 μm, or a chip with a length of 4 mm, a width of 4.6 mm and a thickness of 300 μm.

[0047] S200: positioning the conductive filament 34 by CAFM

[0048] The in-situ chip 1 is placed on the test platform of the conductive probe atomic force microscope 2, and the resistive switching device 3, the connection electrode, the test electrode of the in-situ chip 1 and the test platform are electrically connected, and the cross section of the resistive switching device is scanned by the conductive probe 21 and the position of the conductive filament 34 is determined according to the current distribution. Specifically, referring to Figure 3 , the in-situ chip 1 further comprises a first test electrode 13 and a second test electrode 14, the first test electrode 13 and the first connection electrode 11 are connected by a wire, and the second test electrode 14 and the second connection electrode 12 are connected by a wire. During the CAFM test, one of the first connection electrode 11 and the second connection electrode 12 is grounded, and the other is suspended.

[0049] According to some embodiments of the present application, the size of the needle tip of the CAFM conductive probe 21 can be 5 nm, so as to improve the resolution of the current distribution test.

[0050] According to some embodiments of the present application, during the CAFM test, oxygen isotope gas can also be introduced into the first test cavity. Specifically, the oxygen isotope gas can be introduced into the first test cavity through the oxygen isotope carrier gas system.

[0051] The specific introduction method of the oxygen isotope gas is described in detail as follows:

[0052] According to some embodiments of the present application, referring to Figure 6 , the oxygen isotope gas can be introduced into the first test cavity before the in-situ chip 1 is placed in the first test cavity, and the in-situ chip 1 is placed on the test platform in the oxygen isotope atmosphere to perform the resistive switching operation. Under the action of the electric field, the oxygen isotope gas is ionized into oxygen ions, which enter the resistive switching region from the interface or the surface of the resistive switching layer 32, participate in the oxygen ion migration process under the electric field loading condition, and determine the migration path of the oxygen ions in the resistive switching process of the resistive switching device 3. Then, the distribution of the oxygen isotope is tested by the ion mass spectrometer, so as to mark the distribution area of the oxygen ions.

[0053] According to some other embodiments of the present application, referring to Figure 7 , the oxygen isotope gas can also be introduced into the first test cavity after the resistive switching device 3 completes the resistive switching. Specifically, the in-situ chip 1 is first placed on the test platform in the vacuum or inert gas atmosphere to perform the resistive switching operation, so that the conductive channel composed of oxygen vacancies is formed in the resistive switching layer 32 of the resistive switching device 3. After the resistive switching is completed, the oxygen isotope gas is introduced into the first test cavity, and a read voltage is loaded to ionize the oxygen isotope gas into oxygen ions, which neutralize the oxygen vacancies in the resistive switching layer 32. The distribution of the oxygen isotope, which represents the distribution of the oxygen vacancies, is tested by the ion mass spectrometer, so as to determine the morphology and distribution of the conductive filament 34.

[0054] S300: TEM observation of the microscopic information of the cross-section of the resistive switching device.

[0055] In this step, transmission electron microscopy (TEM) is used to test the microstructure information of the resistive switching device cross-section, including the crystal structure of the conductive filament 34, the interior of the resistive switching layer 32, and the microstructure and composition distribution at the upper and lower interfaces of the resistive switching layer 32. Specifically, the in-situ chip 1 can be placed on the in-situ sample holder of the TEM, and then tested using the TEM.

[0056] Example 1

[0057] TiN / TaO2 / HfO x Characterization of conductive filaments in the resistive switching device 3 with a TiN structure:

[0058] Figure 8 The in-situ chip for the resistive switching device prepared by focused ion beam adopts the Protochip in-situ power-on test chip structure. The resistive switching device on the chip is 15um long and 10um wide. The resistive switching device is placed between two connecting electrodes by Pt deposition of conductive lines. Figure 9 This is a magnified scanning electron microscope image of the resistive switching stacked structure. Current distribution in the resistive layer region was measured using CAFM contact mode. To improve the resolution of the CAFM current measurement, a conductive probe with a tip size of 5 nm was used. The CAFM test parameters were adjusted to control the magnitude of the acquired electrical signal to the pA level to prevent the current signals from the upper and lower electrodes from overshadowing the current signals of the conductive filaments in the resistive switching layer. The first CAFM test showed the current distribution of the resistive switching device under high resistance conditions. The upper electrode was grounded, the CAFM conductive probe was connected to the upper electrode, the resistive switching layer was in an insulated state, and the current at the lower electrode was in the pA range. Figure 10 As shown in the diagram. The second CAFM test of the low-resistivity device shows a current distribution. A conductive path was detected in the resistive switching layer 32 region; therefore, the upper and lower electrodes 31 are in a conductive state, as shown. Figure 11 As shown.

[0059] Depend on Figure 10 It can be seen that after cutting, the resistive switching device, without electrical resistive switching operation, lacks conductive filaments. Therefore, the current distribution between the upper and lower electrodes differs significantly, the resistive switching layer is in an insulating state, and there is no current signal. Figure 11 It can be seen that conductive filaments are formed inside the resistive switching device on the in-situ chip. In the CAFM test results, it can be seen that the upper and lower electrodes are connected, and there are locally distributed conductive channels inside the resistive switching layer.

[0060] In the description of the present application, it is to be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements 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.

[0061] In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of 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 "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0062] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0063] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0064] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0065] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A testing device for conductive filaments in an oxygen vacancy-type resistive switching device, characterized in that, The application comprises: a focused ion beam microscope adapted to cut a resistive switching device to form a resistive switching device section, so that the upper electrode section, the resistive switching layer section and the lower electrode section of the resistive switching device are exposed in the same plane; an in-situ chip on which a bearing surface adapted to bear the resistive switching device is formed, the bearing surface being provided with a connecting electrode and a test electrode; a conductive probe atomic force microscope provided with a first test cavity adapted to accommodate the in-situ chip, the first test cavity being provided with a test platform, the resistive switching device, the connecting electrode, the test electrode and the test platform being electrically connected, the conductive probe scanning the resistive switching device section and determining the position of the conductive filament according to the current distribution; a transmission electron microscope adapted to observe the position of the conductive filament to obtain the microstructure of the conductive filament. The application further comprises: an oxygen isotope carrier gas system comprising a carrier gas source in communication with the first test cavity; an ion mass spectrometer adapted to test the distribution area of oxygen ions according to the position of oxygen isotopes.

2. The test device of claim 1, wherein, The oxygen isotope carrier gas system further comprises a flow regulator arranged between the carrier gas source and the first test cavity.

3. A method of testing a conducting filament in an oxygen-vacancy-based resistive switching device, the method comprising: applying a first voltage to the device; applying a second voltage to the device; and measuring a current through the device. The application comprises: cutting a resistive switching device to form a resistive switching device section by using a focused ion beam microscope, so that the upper electrode section, the resistive switching layer section and the lower electrode section of the resistive switching device are exposed in the same plane; placing the cut resistive switching device on an in-situ chip and electrically connecting the resistive switching device with a connecting electrode of the in-situ chip, the resistive switching device section facing a bearing plane of the in-situ chip; placing the in-situ chip on a test platform in a first test cavity of a conductive probe atomic force microscope, electrically connecting the resistive switching device, the connecting electrode, a test electrode of the in-situ chip and the test platform, and scanning the resistive switching device section by using a conductive probe and determining the position of the conductive filament according to the current distribution; observing the conductive filament by using a transmission electron microscope to obtain the microstructure of the conductive filament. The application further comprises: passing an oxygen isotope gas into the first test cavity through an oxygen isotope carrier gas system, and testing the distribution of the oxygen isotopes in the resistive switching device by using an ion mass spectrometer.

4. The method of claim 3, wherein, The oxygen isotope gas is passed into the first test cavity before the resistive switching device is subjected to resistive switching.

5. The method of claim 3, wherein, The oxygen isotope gas is passed into the first test cavity after the resistive switching device is subjected to resistive switching.

6. The method of claim 3, wherein, The method of placing the cut resistive switching device on the in-situ chip and connecting the resistive switching device with the connecting electrode of the in-situ chip comprises forming a Pt-made deposited wire between the resistive switching device and the connecting electrode by ion beam deposition.

7. The method of claim 3, wherein, The resistive switching device is thinned after the resistive switching device section is formed by using the focused ion beam microscope.

8. The method of claim 7, wherein, The thickness of the thinned resistive switching device is not greater than 50 nm.

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