Device and method for high-throughput testing of electrical properties of a compositionally graded thin film material

Abstract

The present application relates to a kind of high-throughput testing device and method of electrical properties of component gradient film material, belong to material performance test field, solve the problem that the measurement result is wrong caused by the easy damage of scanning probe to sample.It includes: probe device, located above the sample to be measured, including probe and its fixing device, for detecting the response of sample to external field;Electrical property testing device, for applying external field to sample, collecting the response signal detected by probe, and transmitting the collected data to computer;Displacement device, for loading sample and adjusting the position of sample;Probe-sample distance monitoring device, for real-time monitoring the distance between probe and sample and feeding back to computer;Computer, for controlling displacement device to stop moving at the moment when probe and sample contact, and calculating the electrical properties of sample based on the collected data.The testing device of electrical properties of component gradient film is realized, which can effectively avoid sample damage, fast, efficient and accurate.

Description

Technical Field

[0001] This invention relates to the field of material performance analysis and testing technology, and in particular to an apparatus and method for high-throughput testing of the electrical properties of composition gradient thin film materials. Background Technology

[0002] Thin film materials have shown great application potential in fields such as microelectronics and communication systems. Testing the ferroelectric and dielectric properties of thin film materials, such as hysteresis loop, dielectric constant, and leakage current, is fundamental to their application. With the development of parallel synthesis technology in materials genome engineering, in-situ physical mask sequential deposition technology has been achieved. This technology involves uniformly depositing one component of the film while simultaneously moving the physical mask above it to obtain a compositional gradient along that direction. This results in multi-component gradient films, where different locations contain different compositions, thus encompassing a complete library of compositional materials. Composition-gradient ferroelectric and dielectric thin films are characterized by a huge number of small and densely packed composition points. Testing their electrical properties requires high-throughput characterization equipment to rapidly measure the electrical properties of films containing a large number of composition points.

[0003] However, existing electrical performance testing equipment, such as ferroelectric analyzers and impedance analyzers, are designed for single samples with a single component and cannot be directly used for high-throughput testing.

[0004] Existing technology discloses a high-throughput electrical testing device. Compared to the scanning four-probe technique, which is suitable for large-size materials, the device disclosed in this invention can achieve high-throughput electrical testing of micro- and nano-sized materials. However, both the scanning four-probe technique and this patent are used to measure the resistivity of conductive materials, but cannot measure the ferroelectric and dielectric properties of dielectric thin-film insulating materials. In addition, scanning probe microscopy techniques such as scanning near-field microwave microscopy and scanning capacitance microscopy can perform spatially resolved automated electrical performance testing of thin film samples, but they are mainly for nanoscale samples, with harsh working conditions, slow scanning speed, and small scanning range, making them unsuitable for larger samples at the millimeter or hundred-micrometer scale. Moreover, the aforementioned scanning probe microscopy techniques typically use a probe stage to perform spatially resolved electrical performance testing of thin film samples, but traditional probes are made of hard alloy material, which has high hardness and exerts high pressure on the sample. For thin films with thicknesses as low as a few nanometers and top electrode thicknesses as low as tens of nanometers, these hard probes can easily damage the thin film, affecting the test results.

[0005] In summary, existing electrical measurement devices have the following shortcomings: 1) They cannot measure the electrical properties of insulating thin film materials containing a large number of component points; 2) The scanning probe microscopy device has a slow scanning speed and low detection efficiency; 3) The hard probe used in the scanning probe microscopy device is prone to damaging the thin film, affecting the detection results. Summary of the Invention

[0006] Based on the above analysis, the present invention aims to provide a high-throughput testing device and method for the electrical properties of composition gradient thin film materials, in order to solve the problem that existing devices cannot rapidly measure the electrical properties of insulating thin film materials containing a large number of composition points.

[0007] On one hand, embodiments of the present invention provide a high-throughput testing device for the electrical properties of composition gradient thin film materials, comprising: a probe device placed above the sample to be tested; including a probe and its fixing device, used to detect the sample's response to an external field; the sample to be tested is a composition gradient thin film containing multiple closely arranged composition points of millimeter-scale size; an electrical performance testing device, with measurement ports connected to the sample and the probe respectively, and a signal output terminal connected to a computer; used to apply an external field to the sample, simultaneously acquire the response signal detected by the probe, and transmit the acquired data to the computer for further calculation and display; a displacement device connected to the computer, used to load the sample to be tested, and adjust the position of the sample to be tested under the control of the computer; and a probe-sample distance monitoring device connected to the computer, used to monitor the distance between the probe and the sample in real time and feed it back to the computer; the computer controls the displacement device to stop moving at the instant the probe contacts the sample.

[0008] Specifically, the probe-sample distance monitoring device is an industrial camera, which is placed to the side of the probe with its lens aligned with the probe and at a small angle to the sample surface normal.

[0009] Specifically, the probe-sample distance monitoring device is a probe-sample capacitance feedback device, which is electrically connected to the sample and the probe, applies a voltage signal to the sample, and measures the capacitance value between the probe and the sample; the capacitance value characterizes the distance between the probe and the sample.

[0010] Specifically, the probe-sample capacitance feedback device includes: a signal generator, a lock-in amplifier, and an operational amplifier; wherein, the signal generator is connected to the sample and applies a frequency of [frequency missing]. Amplitude The operational amplifier receives and amplifies the current signal generated by the probe tip, and transmits it to the lock-in amplifier. The two inputs of the lock-in amplifier are connected to the output of the signal generator and the output of the operational amplifier, respectively. The output of the lock-in amplifier is connected to a computer to extract the frequency signal. The output voltage and its amplitude are obtained. The data is transmitted to a computer to calculate the capacitance value.

[0011] Specifically, the probe is either a hard probe or a soft probe.

[0012] Furthermore, the soft probe is a conductive polymer soft probe, liquid metal, or a soft probe.

[0013] Specifically, the displacement device includes: a platform and A lead screw stepper motor; among which, The lead screw stepper motor is computer-controlled, enabling the sample above the stage to move in space.

[0014] On the other hand, embodiments of the present invention provide a high-throughput testing method for the electrical properties of composition-gradient thin film materials, which uses the aforementioned high-throughput testing device to perform the measurement and includes the following steps:

[0015] Prepare composition gradient thin film samples, including a substrate, a composition gradient thin film deposited on the substrate and a bottom electrode, and a top electrode deposited on the surface of the thin film to be tested;

[0016] Place the sample on the displacement device and fix the probe above the sample;

[0017] The computer-controlled displacement device adjusts the spatial position of the sample so that position A of the sample contacts the probe device. During the adjustment process, the probe-sample distance monitoring device monitors the distance between the probe and the sample in real time and feeds it back to the computer. At the moment of contact, the computer instructs the displacement device to stop moving.

[0018] An electrical performance testing device was used to test the electrical performance of sample A, and the measurement data was transmitted to a computer.

[0019] The computer processes the measurement data and displays the electrical performance results at location A;

[0020] The computer then controls the displacement device again to bring the next measurement position B into contact with the probe; the above detection process is repeated using an electrical performance testing device until all positions of the sample have been tested.

[0021] Specifically, the probe is a rigid probe. The computer then controls the displacement device to bring the next measurement position B into contact with the probe. The specific operation is as follows:

[0022] The computer-controlled displacement device first moves the sample downward, away from the probe; then moves the sample horizontally so that the measurement position B is directly opposite the probe; finally, it moves the sample vertically upward so that the measurement position B contacts the probe.

[0023] Specifically, the probe is a soft probe. The computer then controls the displacement device to bring the next measurement position B into contact with the probe. The specific operation is as follows:

[0024] The computer-controlled displacement device moves the sample horizontally until the measurement position B comes into contact with the probe.

[0025] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0026] 1. Compared with existing high-throughput electrical measurement devices for measuring conductor resistivity, this device can measure the electrical properties of composition gradient thin-film insulating materials;

[0027] 2. By using a probe-sample distance monitoring device, damage to the thin film by the probe can be effectively avoided, which protects the thin film material and makes the measurement results more accurate.

[0028] 3. When using a soft probe for detection, it is easier to change the sample measurement position, thus the scanning speed is faster and the detection efficiency is higher.

[0029] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0030] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0031] Figure 1 This is a schematic diagram of the overall device of the present invention;

[0032] Figure 2 This is a frontal view of the structure of the sample to be tested;

[0033] Figure 3 This is a schematic diagram of a probe-sample capacitance feedback device;

[0034] Figure 4 This is a top view of the structure of the sample to be tested;

[0035] Figure 5 A schematic diagram of the structure of a liquid metal or ionic liquid type soft probe;

[0036] Figure label:

[0037] 1-Electrical performance testing device; 2-Probe; 2-1-Electric push rod; 2-2-Needle; 2-3-Droplet; 3-Sample to be tested; 3-1-Substrate; 3-2-Composition gradient thin film; 3-3-Bottom electrode; 3-4-Top electrode; 4-Displacement device; 5-Probe-sample capacitance feedback device; 5-1-Signal generator; 5-2-Operational amplifier; 5-3-Lock-in amplifier; 6-Industrial camera; 7-Computer. Detailed Implementation

[0038] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0039] A specific embodiment of the present invention discloses a device for high-throughput testing of the electrical properties of composition gradient thin film materials, such as... Figure 1 As shown, it includes: a probe device located above the sample to be tested, including a probe and its fixing device, for detecting the sample's response to an external field; an electrical performance testing device for applying an external field to the sample, simultaneously acquiring the response signal detected by the probe, and transmitting the acquired data to a computer; a displacement device for loading the sample to be tested and adjusting the position of the sample; a probe-sample distance monitoring device for real-time monitoring of the distance between the probe and the sample and feeding it back to the computer; and a computer for controlling the displacement device to stop moving at the instant the probe contacts the sample, and for calculating the electrical performance of the sample based on the acquired data.

[0040] Specifically, such as Figure 2 As shown, the composition gradient thin film sample includes: a substrate, a bottom electrode, a thin film, and a top electrode array; wherein, the thin film is deposited on the substrate, the bottom electrode is deposited at the exposed position of the substrate or on the back side of the substrate, and the top electrode is deposited on the thin film in an array.

[0041] In practice, for example, for a triangular thin film sample with a ternary composition gradient, in order to measure each composition point, the following method is used: Figure 4 The sample is prepared as shown; wherein the substrate is a circular silicon wafer with a diameter of 25 mm, the thin film to be tested is deposited on the substrate in the form of an equilateral triangle, the triangle can be the largest inscribed triangle of a circle with a side length of 21 mm, and the thin film to be tested has an in-plane ternary composition gradient; the bottom electrode is deposited at the exposed position of the substrate or on the back side of the substrate; the top electrodes are deposited on the thin film to be tested in an array at equal intervals, each top electrode is an equilateral triangle with a side length of 0.9 mm, the gap between adjacent top electrodes is 0.1 mm, and a maximum of 21 top electrodes are arranged on each side of the thin film to be tested, and the maximum total number can be 441.

[0042] Specifically, the probe fixing device includes: a probe base, a cantilever, and a probe clamp; the probe base is adjustablely mounted on a fixed platform, which is higher than the plane where the sample is located; one end of the cantilever is connected to the probe base, and the other end is equipped with a probe clamp; the probe clamp is used to fix the probe.

[0043] The probe has conductivity and good electrical contact. It is fixed above the sample by a probe fixing device, and a lead wire is led out from the end of the probe to connect to the electrical performance testing device.

[0044] Specifically, the probe can be a hard or soft probe; for example, a hard probe can be a commercial beryllium copper straight needle or a commercial spring probe, with a probe tip diameter of 0.1-1 mm, and a lead wire extending from the probe end to connect to the electrical performance testing device; for example, a soft probe can be a conductive polymer, liquid metal, or ionic liquid type soft probe; wherein, a conductive polymer soft probe is made by coating the tip of the aforementioned hard probe with a layer of conductive polymer; liquid metal or ionic liquid soft probes, such as... Figure 5 As shown, it includes a syringe, a needle, and an electric actuator. The electric actuator is controlled by a computer. The syringe contains liquid metal or ionic liquid, and a wire is led out from the syringe to connect to an electrical performance testing device. During implementation, by controlling the electric actuator, the liquid is pushed to the nozzle, so that the droplet at the nozzle is kept in a state of not dripping.

[0045] Specifically, the electrical performance testing device includes a ferroelectric analyzer and an impedance analyzer, which are used to measure the ferroelectric and dielectric properties of the sample, respectively. The measurement ports of the electrical performance testing device are connected to the sample and the probe, respectively, and the output port is connected to the computer. An external field is applied to the sample, the response signal detected by the probe is collected, and the measurement data is transmitted to the computer for further calculation. The computer displays the test results.

[0046] During implementation, the ferroelectric analyzer applies a voltage signal to the sample and measures the induced current of the sample in response to the voltage signal using a probe. Based on the voltage signal and the induced current, the ferroelectric analyzer calculates and obtains its hysteresis loop and leakage current.

[0047] During implementation, the impedance analyzer applies a voltage signal to the sample and measures the capacitance between the sample and the probe. Based on the voltage signal and capacitance value, the impedance analyzer calculates the dielectric constant.

[0048] Specifically, the displacement device is used to load the sample and move its position; it includes: a stage, a vacuum pump, and... The three-dimensional lead screw stepper motor has a stage with numerous micropores for air guidance. A vacuum pump located below the stage is used to extract air from below the stage and from the micropores, allowing the sample to be adsorbed and fixed on the stage. The x, y, and z axis stepper motors are computer-controlled to enable the sample to move vertically and horizontally with a displacement accuracy of 1 μm and a travel distance on the order of centimeters.

[0049] Furthermore, the device also includes a probe-sample distance monitoring device, which is connected to a computer to monitor the distance between the probe and the sample in real time, preventing excessive contact between the probe tip and the sample from damaging the sample and causing deviations in the measurement results.

[0050] Specifically, the probe-sample distance monitoring device can use an industrial camera or a probe-sample capacitive feedback device, or both an industrial camera and a probe-sample capacitive feedback device, to jointly monitor the distance between the probe and the sample.

[0051] For example, if an industrial camera is used, during implementation, the industrial camera is connected to a computer and placed to the side of the probe to monitor the distance between the probe and the sample surface in real time. When the probe contacts the sample, the computer immediately commands the sample to stop its displacement in the z-direction. Specifically, the industrial camera forms a small angle with the normal to the sample surface, approximately... Because the sample surface is relatively smooth, under the action of an external light source, the reflection of the probe tip on the sample surface can be clearly seen. As the sample gradually approaches the probe tip, the tip and its reflection also gradually approach each other. When the sample and the tip are in contact, the tip and its reflection will also be in contact. Based on this, the distance between the sample and the tip and whether they are in contact can be determined.

[0052] Alternatively, for example, a probe-sample capacitance feedback device can be used to measure the capacitance formed by the probe and the sample, which can characterize the distance between the probe and the sample; specifically, it includes: a signal generator, an operational amplifier, and a lock-in amplifier; in implementation, the signal generator is connected to the sample bottom electrode, providing it with a frequency of Amplitude The operational amplifier receives and processes the current signal generated by the probe tip; the processed signal is then transmitted to the lock-in amplifier. The two inputs of the lock-in amplifier are connected to the outputs of the signal generator and the operational amplifier, respectively. The output of the lock-in amplifier is connected to a computer to extract the frequency signal. The voltage signal and voltage amplitude are obtained. The data is transmitted to the computer, where the capacitance value is calculated. The operational amplifier's gain is G, and the capacitance value C can be calculated using the following formula:

[0053] ;

[0054] The principle of the probe-sample capacitance feedback device described above is that there is an air medium between the probe tip and the sample, which can be equivalent to a capacitor C; let... The dielectric constant of air is The radius of the needle tip. Let C be the distance from the needle tip to the sample surface. The capacitance C can then be estimated using the following formula:

[0055] ;

[0056] ;

[0057] When the probe is far from the sample, the capacitance value is close to 0 and cannot be detected; when the probe gets close to the sample to the point that the industrial camera cannot distinguish it, the capacitance value increases sharply and can be detected; when the probe touches the sample, the capacitance value immediately drops to 0, and this information is fed back to the computer, which immediately issues a command to stop the sample from moving.

[0058] Alternatively, an industrial camera and a probe-sample capacitance feedback device can be combined to monitor the distance between the probe and the sample surface and whether the probe is in contact with the sample in real time. Typically, industrial cameras have limited resolution. When the probe-sample distance approaches the micrometer level, a probe-sample capacitance feedback device is needed to measure the capacitance formed by the probe and sample, thus more accurately determining whether the probe is in contact with the sample. Once the probe contacts the sample, the computer receives the feedback information and immediately controls the displacement device to stop moving, effectively preventing the probe from damaging the sample.

[0059] Furthermore, a heating device is set between the three-dimensional displacement device and the sample to heat the sample and provide a thermal field testing environment for the sample's electrical properties; specifically, it includes: an insulating sheet, a heating stage, and a heat-insulating base plate. The bottom of the heating stage is a heat-insulating base plate, and the top is an insulating sheet; wherein, the heat-insulating base plate is placed on the displacement stage of the three-dimensional displacement device and can be made of polytetrafluoroethylene, which can effectively reduce heat dissipation and keep the sample temperature stable; the sample is placed on the insulating sheet to avoid charge interference from the heating stage or the displacement stage.

[0060] Another embodiment of the present invention discloses a high-throughput testing method for the electrical properties of composition gradient thin film materials, which uses the testing apparatus described in the above embodiment to perform the measurement. The testing steps include:

[0061] Place the sample on the displacement device and fix the probe above the sample;

[0062] The computer-controlled displacement device adjusts the spatial position of the sample so that position A of the sample contacts the probe device. During the adjustment process, the probe-sample distance monitoring device monitors the distance between the probe and the sample in real time and feeds it back to the computer. At the moment of contact, the computer instructs the displacement device to stop moving.

[0063] An electrical performance testing device was used to test the electrical performance of sample A, and the measurement data was transmitted to a computer.

[0064] The computer processes the measurement data and displays the electrical performance results at location A;

[0065] The computer then controls the displacement device again to bring the next measurement position B into contact with the probe; the above detection process is repeated using an electrical performance testing device until all positions of the sample have been tested.

[0066] Specifically, if the probe is a hard probe, the computer again controls the displacement device to bring the next measurement position B into contact with the probe. The specific operation is as follows:

[0067] The computer-controlled displacement device first moves the sample downward, away from the probe; then moves the sample horizontally so that the measurement position B is directly opposite the probe; finally, it moves the sample vertically upward so that the measurement position B contacts the probe.

[0068] Specifically, if the probe is a soft probe, the computer again controls the displacement device to bring the next measurement position B into contact with the probe. The specific operation is as follows:

[0069] The computer-controlled displacement device moves the sample horizontally until the measurement position B comes into contact with the probe.

[0070] In summary, the aforementioned high-throughput testing device and method for the electrical properties of composition-gradient thin film materials firstly utilizes both an industrial camera and a probe-sample capacitance feedback device to monitor the distance between the probe and the sample surface and whether the probe is in contact with the sample in real time, effectively preventing probe damage to the sample. Secondly, the conductive probe is a soft probe, which, compared to a hard probe, effectively avoids probe damage to the sample and allows for direct horizontal movement to the next testing position on the sample during testing, eliminating sample lifting and lowering time and further improving scanning speed and detection efficiency. Additionally, the device incorporates a heating element to apply a thermal field to the sample, enabling rapid testing of the sample's electrical properties within the thermal field. The device has a wide range of applications.

[0071] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0072] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-throughput testing device for the electrical properties of composition gradient thin film materials, characterized in that, The application relates to a probe-sample distance monitoring device, a probe-sample distance monitoring device, a computer, and a probe-sample distance monitoring device. The probe-sample distance monitoring device is an industrial camera, and the industrial camera is connected with the computer, is arranged on the side of the probe, and has a lens which is aligned with the probe and has an angle with the normal line of the surface of the sample; the probe-sample distance monitoring device is used for collecting the image of the distance between the probe and the sample and transmitting the image to the computer, the distance between the probe and the sample is obtained by analyzing the image by the computer, and the movement and stop of the displacement device are controlled according to the distance between the probe and the sample. The probe is a hard probe or a soft probe. The soft probe is a conductive polymer type soft probe, a liquid metal type soft probe or an ionic liquid type soft probe. The application further relates to a probe-sample distance monitoring method. The sample is placed on the translation device, and the probe is fixed above the sample. The displacement device is controlled by the computer to adjust the spatial position of the sample, so that the position A of the sample is in contact with the probe device; the distance between the probe and the sample is monitored in real time during the adjustment process by the probe-sample distance monitoring device, and the displacement device is stopped by the computer at the moment when the two are in contact. The electrical performance of the sample at the position A is tested by the electrical performance testing device, and the measured data is transmitted to the computer. The probe-sample capacitance feedback device comprises a signal generator, a lock-in amplifier and an operational amplifier; wherein the signal generator is connected with the sample to apply an alternating voltage signal with a frequency of and an amplitude of ; the input end of the operational amplifier is connected with the probe, and the output end is connected with the lock-in amplifier, for receiving and amplifying the current signal generated by the needle tip and transmitting to the lock-in amplifier; the two input ends of the lock-in amplifier are respectively connected with the output end of the signal generator and the output end of the operational amplifier, and the output end of the lock-in amplifier is connected with the computer, for extracting the output voltage with a frequency of , obtaining the amplitude , transmitting to the computer, and calculating the capacitance value.

2. The high-throughput device for electrical property measurement of compositionally-graded thin film materials of claim 1, wherein, The measured data is processed by the computer, and the electrical performance result of the position A is displayed.

3. The high-throughput device for electrical property measurement of compositionally-graded thin film materials of claim 1, wherein, The next measurement position B is in contact with the probe by controlling the displacement device by the computer again; the above detection process is repeated by the electrical performance testing device until all the positions of the sample are tested.

4. The high-throughput device for electrical property measurement of compositionally-graded thin film materials of claim 3, wherein, When the probe is a hard probe, the next measurement position B is in contact with the probe by controlling the displacement device by the computer again, and the specific operation is as follows: the sample is first moved downward and away from the probe by controlling the displacement device by the computer; then the sample is horizontally moved so that the measurement position B is opposite to the probe; finally, the sample is vertically moved upward so that the measurement position B is in contact with the probe.

5. The high-throughput device for electrical property measurement of compositionally-graded thin film materials of claim 1, wherein, The displacement device comprises a carrier and a three-dimensional A shaft screw stepping motor; wherein the carrier is used for placing a sample, The shaft screw stepping motor is controlled by a computer to move the sample above the carrier in space.

6. A high-throughput testing method for electrical properties of a compositionally-graded thin film material, wherein the high-throughput testing method is implemented by using the high-throughput testing device of claim 1, and wherein the high-throughput testing method comprises: providing the high-throughput testing device; and performing the high-throughput testing method by using the high-throughput testing device. When the probe is a soft probe, the next measurement position B is in contact with the probe by controlling the displacement device by the computer again, and the specific operation is as follows: the sample is horizontally moved by controlling the displacement device by the computer so that the measurement position B is in contact with the probe. ​ ​ ​ ​ ​ 7. The method of claim 6, wherein the method further comprises: ​ ​ 8. The method of claim 6, wherein the method further comprises: ​ ​

Images