CN107064565B - Magneto-electric-thermal multiparameter coupling microscope probe, preparation method and detection method thereof - Google Patents

Abstract

The invention provides a magneto-electric-thermal multiparameter coupling microscope probe, which comprises a probe arm and a probe tip body connected with the probe arm, wherein a thermoelectric couple layer, a heat conduction insulating layer and a magnetic electric conduction layer are sequentially covered outwards from the surfaces of the probe arm and the probe tip body; the thermoelectric couple layer and an external circuit form a thermoelectric loop; the magnetic conductive layer and the sample and external circuit form a conductive loop. The probe has a simple structure and low preparation difficulty, can detect magnetic signals, electric signals and thermal signals of magneto-electric functional materials in situ in a micro-area, and can effectively avoid signal interference between a thermoelectric loop and an electric loop.

Description

Magnetic-electric-thermal multi-parameter coupling microscope probe, preparation method and detection method thereof

Technical Field

The invention relates to a probe of a scanning probe microscope, in particular to a magnetic-electric-thermal multi-parameter coupling microscope probe, and a preparation method and a detection method thereof.

Background technique

With the rapid development of information technology, the electronic components of integrated circuits tend to be miniaturized and integrated. The size of electronic components has entered the micro/nano scale, and the problem of heat generation and heat dissipation has become a bottleneck problem that restricts further high integration. Characterizing heat-related physical properties at the micro/nano scale and understanding the physical process of heat generation and heat dissipation has become a new branch of modern thermal science - micro/nanoscale thermal science. At the micro/nano scale, the influence of the microstructure and domain structure of the material (for magnetic and ferroelectric materials) on the thermal properties is particularly important. A microcrack, hole, grain boundary, or even a domain wall may affect the thermal properties of the material. Taking multiferroic materials as an example, magnetic/electric domain reversal (or domain wall movement) and leakage current driven by external fields will cause micro-region heating. Although people have developed a variety of technical means to study these parameters, so far, there is no technology and equipment that can perform in-situ, real-time, and synchronous comprehensive characterization of these parameters, which limits the in-depth understanding of the physical mechanism of heat generation and heat dissipation in materials, and thus it is impossible to find a solution to the problem of heat generation and heat dissipation of materials at the micro/nano scale.

As an important research method for nanoscience and technology, atomic force microscopy has developed rapidly. Scanning probe microscopy is developed based on scanning tunneling microscopy. It has many advantages such as high spatial resolution and the ability to work at variable temperatures in a variety of environments such as vacuum, atmosphere, and even solution. It has been widely used in research fields such as physics, chemistry, biology, and electronics. People detect the surface morphology and other physical properties of samples by detecting various interaction forces or physical quantities such as current between the probe and the sample surface. Atomic force microscopy, magnetic force microscopy, piezoelectric force microscopy, conductive force microscopy and other technologies have been developed to detect sample surface morphology, domain structure, micro-area conductivity, and other physical parameters.

In recent years, scanning thermal probe technology has been developed, which has expanded scanning probe microscopy technology to the field of thermal research, and has achieved the spatial distribution characterization and research of thermal properties such as temperature and thermal conductivity of micro-areas on the surface of materials and devices. Although people have developed micro-area thermal imaging technology based on scanning probe microscopy, at present, this technology can only obtain thermal information in a single way, and cannot simultaneously obtain a lot of information such as magnetic domain structure, ferroelectric/piezoelectric domain structure, and conductive domain structure in real time in situ. In particular, people are still unclear about the correlation between them, and it is impossible to perform magnetic-electric-thermal coupled imaging, which limits the in-depth understanding of the physical mechanism of heat generation and heat dissipation in materials, and thus it is impossible to find a solution to the heat generation and heat dissipation problems of materials at the micro/nano scale.

The present invention proposes a novel nano-magnetic-electric-thermal multi-parameter coupled microscope probe, which will overcome the limitations of the existing single magnetic, electrical and thermal functional modules, develop a probe with both magnetic-electric-thermal property detection, and equip it with a corresponding signal detection and processing system, which will be able to achieve in-situ characterization of changes in magnetic domains, ferroelectric domains, micro-area conductivity, micro-area heating properties and their mutual correlation. Therefore, in the field of nano-testing technology, the development of novel nano-characterization technology, especially probe characterization technology, is one of the current research hotspots in related research fields.

Summary of the invention

In view of the above technical status, the present invention provides a nanomagnetic-electric-thermal multi-parameter coupling microscope probe, which has a simple structure and can measure multiple physical parameters such as magnetism, electricity, and heat in situ and synchronously, so as to realize the study of the influence of magnetic domains and electric domains on thermal properties.

The technical solution of the present invention is: a magnetic-electric-thermal multi-parameter coupling microscope probe, comprising a probe arm and a needle tip body connected to the probe arm, wherein the tip of the needle tip body is used to contact or non-contact with a sample to measure a sample signal; the feature is that: from the surface of the needle tip body outward, there are a thermocouple layer, a heat-conducting insulating layer, and a magnetic conductive layer in sequence;

The thermocouple layer covers the area A and area B on the surface of the needle tip body, and the area on the surface of the needle tip body other than area A and area B is the remaining area, and area A and area B have no overlapping area and are connected at the tip of the needle tip body; the material covering area A is material A, and the material covering area B is material B, and material A is different from material B, and forms a thermoelectric loop with the external circuit;

The thermally conductive insulating layer covers the thermocouple layer and the remaining area of the needle tip body surface;

The magnetic conductive layer is located on the surface of the heat-conducting insulating layer, covers at least the tip of the needle tip body, and forms a conductive loop with the sample and the external circuit.

The three-dimensional structure of the needle tip body is not limited, and can be a pyramid, a cone, a truncated cone, a frustum, or the like.

In order to improve the detection sensitivity, preferably, the area A and the area B are not connected except at the tip of the needle.

Preferably, the probe arm surface includes region A’ and region B’, region A’ and region B’ have no overlapping area, region A’ is connected to region A, and region B’ is connected to region B; the external circuit includes material A covering the surface of region A’ and material B covering the surface of region B’.

The material A and the material B are conductive, and the two are connected to form a loop. When the temperature of the connection point changes, a potential difference is generated in the thermocouple loop. The material A is not limited, including one material or a combination of two or more metals and semiconductors with good electrical conductivity, such as palladium, gold, bismuth (Bi), nickel (Ni), cobalt (Co), potassium (K) and other metals and their alloys, and at least one of semiconductors such as graphite and graphene. The material B is not limited, including one material or a combination of two or more metals and semiconductors with good electrical conductivity, such as palladium, gold, bismuth (Bi), nickel (Ni), cobalt (Co), potassium (K) and other metals and their alloys, and at least one of semiconductors such as graphite and graphene.

The thermally conductive insulation has thermal conductivity and electrical insulation, and its material is not limited, including semiconductors, inorganic materials or organic materials with certain insulation properties, such as zinc oxide (ZnO), bismuth ferrite (BiFeO ₃ ), lithium cobalt oxide (LiCoO ₂ ), nickel oxide (NiO), cobalt oxide (Co ₂ O ₃ ), copper oxide (Cu _x O), silicon dioxide (SiO ₂ ), silicon nitride (SiN _x ), titanium dioxide (TiO ₂ ), tantalum pentoxide (Ta ₂ O ₅ ), niobium pentoxide (Nb ₂ O ₅ ), tungsten oxide (WO _x ), hafnium dioxide (HfO ₂ ), aluminum oxide (Al ₂ O ₃ ), graphene oxide, amorphous carbon, copper sulfide (Cu _x S), silver sulfide (Ag ₂ S), amorphous silicon, titanium nitride (TiN), polyimide (PI), polyamide (PAI), polyschiff base (PA), polysulfone (PS), etc. At least one of the following.

The magnetic conductive layer has magnetic properties and electrical conductivity, and its material is not limited, including ferromagnetic metals such as iron (Fe), cobalt (Co), nickel (Ni), and magnetic alloys.

In order to facilitate the connection with the external circuit, the ferromagnetic conductive layer can also cover other parts of the needle tip body except the tip. As an implementation method, in the working state, the ferromagnetic conductive layer is in contact with the sample, the sample is grounded, and the external circuit is connected to the ferromagnetic conductive layer, that is, the external circuit, the ferromagnetic conductive layer, the sample and the ground form an electrical circuit for measuring the electrical signal of the sample.

The present invention also provides a method for preparing the above-mentioned magnetic-electric-thermal multi-parameter coupling microscope probe, comprising the following steps:

Step 1: using magnetron sputtering technology to deposit material A on the surface of area A of the needle tip body and material B on the surface of area B to obtain a thermocouple layer;

Step 2: Depositing a thermally conductive insulating layer on the surface of the thermocouple layer and the remaining area of the tip body except area A and area B by using magnetron sputtering technology or pulsed laser technology;

Step 3: Deposit a magnetic conductive layer on the surface of the thermal conductive insulating layer using magnetron sputtering technology.

The magnetic-electric-thermal multi-parameter coupling microscope probe of the present invention can detect the morphology, magnetic signal, electrical signal and thermal signal of the sample, and the detection method is as follows:

(1) Surface morphology and magnetic signal detection of samples

Use contact mode.

That is, the probe driving unit drives the probe so that the tip of the needle tip body is displaced to a certain initial position on the sample surface, and the probe performs a direction scan on the sample surface from the initial position. During the scanning process, the tip of the needle tip body is controlled to be in point contact or vibration point contact with the sample surface, and the displacement signal or vibration signal of the needle tip body is collected, and the topography signal of the sample is obtained through analysis;

The probe returns to the initial position and is lifted up a certain distance, and then scans the sample surface according to the orientation. During the scanning process, the tip of the needle tip body is controlled to displace or vibrate along the topographic image, and the displacement signal or vibration signal of the needle tip body is collected, and the magnetic signal image of the sample is obtained after analysis.

(2) Thermal signal detection of samples

The external circuit and the thermocouple layer of the probe form a closed thermoelectric loop. When the temperature of the connection point changes, the potential difference changes in the thermocouple loop. When the tip of the needle body contacts the sample surface, the tip body and the sample exchange heat through the covering layers of the tip, causing the potential difference in the thermal loop to change. After collection and analysis, the thermal signal image of the sample is obtained.

(3) Detection of electrical signals of samples

The tip of the needle body contacts the sample surface, and the external circuit, the magnetic conductive layer of the probe, and the sample form a closed electrical circuit, that is, the electrical signal flows into the magnetic conductive layer of the probe and the sample to form a voltage signal, which is collected and analyzed to obtain an electrical signal image of the sample.

Compared with the prior art, the present invention adopts a thermocouple structure, in which the thermocouple layer and the external power source independently constitute a thermoelectric circuit, the sample to be tested, the magnetic conductive layer and the external power source independently constitute an electric circuit, and the thermal conductive insulation layer is located between the thermal resistor layer and the magnetic conductive layer, which effectively blocks the signal interference between the thermoelectric circuit and the electric circuit, and can perform in-situ micro-area detection of magnetic signals, electric signals and thermal signals of magnetoelectric functional materials, including in-situ micro-area detection of magnetic signals, electric signals and thermal signals at micron and nanometer scales.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a schematic diagram of the front structure of the probe arm and the needle tip body of the magnetic-electric-thermal multi-parameter coupling microscope probe in Example 1 of the present invention;

FIG2 is a schematic diagram of the side structure of FIG1;

FIG3 is an enlarged schematic diagram of the thermocouple layer on the surface of the needle tip body shown in FIG1 ;

FIG4 is a schematic diagram of the structure of the thermocouple layer and part of the external circuit shown in FIG3 ;

FIG5 is a schematic diagram of the structure of the probe surface covered with a thermally conductive insulating layer as shown in FIG4 ;

6 and 7 are schematic diagrams of the structure in which the surface of the probe shown in FIG. 5 is covered with a magnetic conductive layer.

Among them: 1 probe arm, 2 needle tip body, 3 one side of the needle tip body, 4 another side of the needle tip body, 5 the front side of the needle tip body, 6 the back side of the needle tip body, 7 thermal insulation layer, 8 magnetic conductive layer.

Detailed ways

The present invention is further described in detail below in conjunction with examples. It should be pointed out that the following examples are intended to facilitate the understanding of the present invention and are not intended to limit the present invention in any way.

Embodiment 1:

In this embodiment, a commercially available uncoated Si probe is selected, and its structure is shown in Figure 1, including a probe arm 1 and a needle tip body 2 connected to the probe arm 1. As shown in Figures 1 and 2, the needle tip body 2 is a tetrahedral pyramid structure, consisting of a front side 5, a back side 6 opposite to the front side, and two side surfaces 3 and 4.

As shown in FIG3 , the surface of the needle tip body is divided into region A, region B, and the region other than region A and region B is the remaining region. In FIG3 , the region filled with lines on the surface of the needle tip body is region A (i.e., one side surface 3 of the needle tip body), and the region filled with rectangles is region B (i.e., the other side surface 4 of the needle tip body). Region A and region B have no overlapping area and are connected only at the tip of the needle tip body.

As shown in Figure 4, the probe arm surface includes area A’ and area B’. The area filled with lines on the probe arm surface in Figure 4 is A’, and the area filled with rectangles is B’. Area A’ and area B’ have no overlapping area and are not connected. Area A’ is connected to area A, and area B’ is connected to area B.

The following covering layer was prepared on the probe surface.

(1) The uncoated Si probe was cleaned with 50,000 Hz ultrasonic wave for 5 min.

(2) As shown in FIG3 , a mask plate of a specific shape and size is designed, and platinum is evaporated on the surface of region A and gold is evaporated on the surface of region B by using magnetron sputtering technology or pulsed laser technology to form a thermocouple layer. Furthermore, as shown in FIG4 , platinum is evaporated on the surface of region A’ and gold is evaporated on the surface of region B’ to form a part of the external circuit. The thermocouple layer and the external circuit form a thermoelectric loop for measuring the thermal signal of the sample.

(3) As shown in FIG5 , silicon dioxide is deposited on the surface of the thermocouple layer and the surface of the remaining area of the needle tip body (i.e., the front side 5 and the back side 6 of the needle tip body) except area A and area B by using magnetron sputtering technology or pulsed laser technology to obtain a thermally conductive insulating layer 7, as shown by the horizontal line filling in FIG5 ;

(4) As shown in FIG6 , an iron-based magnetic conductive layer 8 is deposited on the surface of the thermocouple layer and the surface of the thermal conductive insulating layer by magnetron sputtering technology or pulsed laser technology, as shown by the grid lines filled in FIG6 . The ferromagnetic conductive layer is connected to an external circuit. In the working state, the ferromagnetic conductive layer is in contact with the sample, the sample is grounded, and the external circuit is connected to the ferromagnetic conductive layer, that is, the external circuit, the ferromagnetic conductive layer, the sample and the ground form an electrical circuit for measuring the electrical signal of the sample.

When the probe prepared above is used to detect the morphology and magnetic signal, thermal signal and electrical signal of the sample, the detection method is as follows:

(1) Used to detect the surface morphology and magnetic signals of samples

The probe driving unit drives the probe so that the tip of the needle tip body is displaced to a certain initial position on the sample surface. The probe performs a directional scan on the sample surface in a transverse direction from the initial position. During the scanning process, the tip of the needle tip body is controlled to be in point contact or vibration point contact with the sample surface, and a longitudinal displacement signal or vibration signal of the needle tip body is collected, and a topographic signal of the sample is obtained through analysis.

The probe returns to the initial position and is lifted upward for a certain distance, and then scans the sample surface according to the transverse orientation. During the scanning process, the tip of the needle tip body is controlled to longitudinally displace or vibrate along the topographic image, and the longitudinal displacement signal or vibration signal of the needle tip body is collected, and the magnetic signal image of the sample is obtained through analysis;

(2) Used to detect the thermal signal of the sample

The external circuit and the thermocouple layer of the probe form a closed thermal loop. When the temperature of the connection point at the tip of the needle changes, the potential difference changes in the thermocouple loop. The probe driving unit drives the probe to move to a certain position on the sample surface, so that the tip of the needle body contacts the sample surface. The needle body exchanges heat with the sample through each covering layer, so that the potential signal in the thermal loop changes. After collection and analysis, a thermal signal image of the sample is obtained.

(3) Used to detect the electrical signal of the sample

The probe driving unit drives the probe to move to a certain position on the sample surface, so that the tip of the needle body contacts the sample surface, and the external circuit, the magnetic conductive layer of the probe, and the sample form a closed electrical circuit, that is, the electrical signal flows into the magnetic conductive layer of the probe and the sample to form a voltage signal. After collection and analysis, an electrical signal image of the sample is obtained.

Embodiment 2:

In this embodiment, the probe structure is substantially the same as the Si probe structure in Embodiment 1, the only difference being that the step (4) is as follows:

As shown in FIG7 , an iron-based magnetic conductive layer 8 is deposited on the surface of the thermocouple layer and the surface of the thermally conductive insulating layer by magnetron sputtering technology or pulsed laser technology, as shown by the grid lines filled in FIG7 . That is, compared with FIG6 , the iron-based magnetic conductive layer 8 in FIG7 covers the entire front surface of the probe needle tip and the front end of the probe body, and this structure facilitates the magnetic conductive layer to connect to the external circuit. In the working state, the ferromagnetic conductive layer contacts the sample, the sample is grounded, and the external circuit is connected to the ferromagnetic conductive layer, that is, the external circuit, the ferromagnetic conductive layer, the sample and the ground form an electrical circuit for measuring the electrical signal of the sample.

The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims (8)

1. A magnetic-electric-thermal multi-parameter coupling microscope probe, comprising a probe arm and a needle tip body connected to the probe arm, wherein the tip of the needle tip body is used to contact or non-contact with a sample to measure a sample signal; wherein the probe comprises a thermocouple layer, a heat-conducting insulating layer, and a magnetic conductive layer from the surface of the needle tip body outward; The thermocouple layer covers the area A and area B on the surface of the needle tip body, and the area other than area A and area B on the surface of the needle tip body is the remaining area, and area A and area B have no overlapping area and are connected at the tip of the needle tip body, and are not connected except for the tip of the needle tip; the material covering area A is material A, and the material covering area B is material B, and material A is different from material B, and a thermoelectric circuit is formed with an external circuit, and material A is deposited on the surface of area A of the needle tip body by magnetron sputtering technology, and material B is deposited on the surface of area B; the probe arm surface includes area A' and area B', and area A' and area B' have no overlapping area, and area A' is connected to area A, and area B' is connected to area B; the external circuit includes material A covering the surface of area A' and material B covering the surface of area B'; when the tip of the needle tip body contacts the sample surface, the tip body and the sample are heat exchanged through the covering layers of the tip, so that the potential difference in the thermal circuit changes, and a thermal signal image of the sample is obtained after collection and analysis; The thermally conductive insulating layer covers the thermocouple layer and the remaining area of the needle tip body surface; The magnetic conductive layer is located on the surface of the heat-conducting insulating layer, covers at least the tip of the needle tip body, and forms a conductive loop with the sample and the external circuit. 2. The magnetic-electric-thermal multi-parameter coupling microscope probe according to claim 1 is characterized in that the three-dimensional structure of the needle tip body includes a pyramid, a cone, a prism, and a truncated cone. 3. The magnetic-electric-thermal multi-parameter coupling microscope probe according to claim 1, characterized in that: the material A is selected from one material or a combination of two or more materials selected from metals and semiconductors with good electrical conductivity; The material B is selected from one material or a combination of two or more metals and semiconductors having good electrical conductivity. 4. The magnetic-electric-thermal multi-parameter coupling microscope probe according to claim 1 is characterized in that: the material A includes one or a combination of two or more of palladium, gold, bismuth, nickel, cobalt, potassium, graphite, and graphene; the material B includes one or a combination of two or more of palladium, gold, bismuth, nickel, cobalt, potassium, graphite, and graphene. 5. The magnetic-electric-thermal multi-parameter coupling microscope probe according to claim 1 is characterized in that the thermal conductive insulating layer material includes one or a combination of two or more of zinc oxide, bismuth ferrite, lithium cobalt oxide, nickel oxide, cobalt oxide, copper oxide, silicon dioxide, silicon nitride, titanium dioxide, tantalum pentoxide, niobium pentoxide, tungsten oxide, hafnium dioxide, aluminum oxide, graphene oxide, amorphous carbon, copper sulfide, silver sulfide, amorphous silicon, titanium nitride, polyimide, polyamide, polyschiff base, and polysulfone. 6. The magnetic-electric-thermal multi-parameter coupling microscope probe according to claim 1 is characterized in that the material of the magnetic conductive layer includes ferromagnetic metals such as iron, cobalt, nickel and magnetic alloys. 7. The method for preparing a magnetic-electric-thermal multi-parameter coupling microscope probe according to any one of claims 1 to 6, characterized in that it comprises the following steps: Step 1: using magnetron sputtering technology to deposit material A on the surface of area A of the needle tip body and material B on the surface of area B to obtain a thermocouple layer; Step 2: Depositing a thermally conductive insulating layer on the surface of the thermocouple layer and the remaining area of the tip body except area A and area B by using magnetron sputtering technology or pulsed laser technology; Step 3: Deposit a magnetic conductive layer on the surface of the thermal conductive insulating layer using magnetron sputtering technology. 8. The method of using the magnetic-electric-thermal multi-parameter coupling microscope probe described in any one of claims 1 to 6 to detect the morphology and magnetic signals, thermal signals and electrical signals of a sample is as follows: (1) Surface morphology and magnetic signal detection of samples In the contact mode, the tip of the needle tip body is displaced to a certain initial position on the sample surface, and the sample surface is directionally scanned from the initial position. During the scanning process, the tip of the needle tip body is controlled to make point contact or vibrate point contact with the sample surface, and the displacement signal or vibration signal of the needle tip body is collected, and the sample morphology signal is obtained through analysis; The probe returns to the initial position and is lifted up a certain distance, and then scans the sample surface according to the orientation. During the scanning process, the tip of the needle tip body is controlled to move or vibrate along the topographic image, and the displacement signal or vibration signal of the needle tip body is collected, and the magnetic signal image of the sample is obtained through analysis; (2) Thermal signal detection of samples The external circuit and the thermocouple layer of the probe form a closed thermoelectric loop. When the temperature of the connection point changes, the potential difference in the thermocouple loop changes. When the tip of the needle tip body contacts the sample surface, the tip tip body and the sample exchange heat through the covering layers of the tip, causing the potential signal in the thermal loop to change. After collection and analysis, a thermal signal image of the sample is obtained. (3) Detection of electrical signals of samples The tip of the needle body contacts the sample surface, and the external circuit, the magnetic conductive layer of the probe, and the sample form a closed electrical circuit, that is, the electrical signal flows into the magnetic conductive layer of the probe and the sample to form a voltage signal, which is collected and analyzed to obtain an electrical signal image of the sample.