CN108198740A - A kind of transmission electron microscope electricity sample lever system in situ - Google Patents

Abstract

The invention relates to the research field of transmission electron microscope accessories and in-situ measurement of low-dimensional materials, in particular to an in-situ electrical sample rod system for a transmission electron microscope. The system includes: a high-vacuum circular airtight connector for conducting electrical signals, a hollow sample rod frame with surface insulation, wires placed in the sample rod frame, a ceramic heating chip, a thermistor, a temperature control unit, and a heating chip Wait. The thermistor and ceramic heating are integrated on the micro-sample stage, connected to the external circuit unit through wires and circular airtight connectors, used to monitor the heating temperature, heating rate and temperature stability of the micro-sample stage; the heating chip is placed in the micro On the sample stage, the temperature of the micro-area of the sample can be further adjusted. The invention maximizes the atomic-scale measurement and research of the macroscopic properties of materials in a vacuum environment and under heating and power-on external field conditions, and is widely applicable to exploring various high-temperature phase transitions, electrical properties, thermoelectric properties, and chemical reactions.

Description

An in-situ electrical sample holder system for transmission electron microscope

technical field

The invention relates to the research field of transmission electron microscope accessories and in-situ measurement of low-dimensional materials, in particular to an in-situ electrical sample rod system for a transmission electron microscope.

Background technique

The structural changes of materials at the sub-nanometer or atomic scale caused by the coupling of the surrounding environment and multi-physics external fields are the root of their macroscopic properties, and whether the microstructure of materials under the action of the environment and external fields can be observed at the sub-nanometer or atomic scale The evolution of structure or chemical composition becomes the key to understanding the properties of materials. The in-situ and real-time high-resolution characterization technology of nanoscale structures and properties under the action of the environment and external fields directly determines our cognition ability of materials, and is the key to realize the design of material structures and related physical and chemical fields in many fields such as guiding information, energy, environment, and biology. The common key technology of performance regulation also directly determines whether my country can continue to maintain its advantages in the international competition of nanotechnology. Therefore, developing nanoscale in-situ, real-time, dynamic characterization methods and detection technologies and improving the limit resolution under the action of external fields has become one of the important research contents in my country's current nanotechnology special projects.

The in-situ transmission electron microscopy analysis technology can be used to study the composition, structure and physical and chemical properties of materials in situ, in real time and dynamically under the conditions of gaseous, liquid, solid and plasma states and external fields such as irradiation, force, heat and electricity. The correlation of the correlation, this kind of analysis and characterization technology has the high-resolution characteristics of time scale and space scale at the same time, it can understand the intrinsic properties of materials from a deep level, promote the design and performance optimization of materials, and greatly improve the research and development efficiency of new materials. The most novel and promising field of research in nanostructure characterization. The main problem is that the advanced analysis and characterization instruments used by my country's scientific research institutes have been heavily dependent on developed countries such as Europe, America and Japan, and almost all high-end analysis equipment such as transmission electron microscope systems are imported. As the microscopic characterization technology with the most development potential, in-situ simulated environment transmission electron microscopy analysis and characterization technology has developed extremely rapidly in developed countries. In recent years, my country has developed in-situ transmission electron microscope analysis and characterization equipment, but it is obviously behind the world's technological powers, and there is still a big gap in the level of related technical equipment. With the gradual increase of support for scientific research in my country, almost all scientific research units and enterprises equipped with TEM in China have the demand for in-situ TEM sample rod systems. However, it is technically difficult to design and manufacture the in-situ simulation environment and multi-field coupling function sample rod system, and the key technologies and core patents are in the hands of foreign companies. Imported by the company, the price is very expensive, accounting for almost half of the price of the transmission electron microscope, which seriously hinders the promotion and use of in-situ transmission electron microscopy characterization technology in my country. The more prominent problem is that the function of the in-situ sample rod system imported from my country is limited, and there is no responsive customization, so it is difficult to change according to the needs of scientific research tasks. Moreover, it can only be imported into the simulated vacuum environment and the in-situ sample rod system with simple thermal and electric external field functions, which is far from meeting the complex and changeable research requirements, and greatly restricts the development of my country's in-situ TEM characterization technology. , not only the content of scientific research is limited, but more importantly, the ability to conduct original research and technology accumulation are lost. Having original scientific research equipment is the prerequisite, basis and strongest guarantee for obtaining original scientific research results. Due to technical limitations, there is no mature commercial TEM sample rod system that can simultaneously realize in-situ heating and power-on functions at home and abroad, and the heating function of the in-situ sample rod exists for high-temperature sample composition analysis (Energy Dispersive Spectroscopy, EDS) has poor accuracy and low anti-interference ability. Based on this appeal and the applicant's solid work foundation in this field for many years, the present invention maximizes the macroscopic analysis of materials in a vacuum environment and under heating and power-on external field conditions. The atomic-scale measurement and research of performance is widely used to explore various high-temperature phase transitions, electrical properties, thermoelectric properties, and chemical reactions.

Contents of the invention

Aiming at the problems existing in the prior art, the object of the present invention is to provide an in-situ electrical sample rod system for a transmission electron microscope, which can realize the macroscopic physical examination of materials in a vacuum environment and under heating and bias external field conditions in a transmission electron microscope. , Atomic scale measurement and research of chemical properties.

Technical scheme of the present invention is:

An in-situ electrical sample rod system for a transmission electron microscope, which sequentially includes a hollow sample rod frame, a high vacuum circular airtight connector for conducting electrical signals, a ceramic heating plate, a thermistor, an external circuit unit, and a hollow The metal wires, micro-sample stage, and heating chip in the sample rod frame have a specific structure as follows:

The sample rod frame is a hollow structure, and an insulating coating is deposited on its surface to avoid potential safety hazards caused by the short circuit between the metal wire and the sample rod frame. The end of the sample rod frame is connected to a high vacuum circular airtight connector that conducts electrical signals. The high-vacuum circular air-tight connector for electrical signals isolates the high vacuum inside the sample rod frame from the external atmosphere, and the high-vacuum circular air-tight connector for conducting electrical signals connects the ceramic heating plate and heat sink at the front end of the sample rod system through metal wires. Sensitive resistance, heating chip and external circuit unit;

Ceramic heaters and thermistors are integrated on the micro-sample stage, connected to external circuit units through metal wires and high-vacuum circular airtight connectors that conduct electrical signals, and are used to monitor the heating temperature and heating rate of the micro-sample stage.

In the in-situ electrical sample rod system for a transmission electron microscope, the micro-sample stage is made of metal, and an 80-120 μm thick Al ₂ O ₃ insulating layer is deposited on the surface to avoid potential safety hazards caused by short circuits between the heating chip and the sample and the micro-sample stage.

In the in-situ electrical sample rod system for a transmission electron microscope, the heating chip is placed in the micro-sample stage for micro-zone temperature regulation and carries various solid samples at the same time. The heating chip is made of aluminum oxide, oxide Silicon, silicon nitride or silicon carbide windows, which have good chemical and physical stability.

In the in-situ electrical sample rod system for the transmission electron microscope, the heating electrode on the heating chip is deposited on the window, and the heating electrode adopts Cr/Au/Al ₂ O ₃ , Ti/Au/Al ₂ O ₃ , Cr/Pt/ Al ₂ O ₃ , Ti/Pt/Al ₂ O ₃ , Cr/Cu/Al ₂ O ₃ Ti/Cu/Al ₂ O ₃ , Cr/Ag/Al ₂ O ₃ or Ti/Ag/Al ₂ O ₃ , heating The Al ₂ O ₃ on the top layer of the electrode is an inert material with high thermal conductivity and insulation, which avoids the reaction between the sample and the window material.

In the in-situ electrical sample rod system for the transmission electron microscope, the heating electrode adopts a four-electrode structure, two electrodes are used for temperature measurement, and two electrodes are used for heating. The heating wires are wrapped around the window to ensure uniform heating of the sample.

In the in-situ electrical sample rod system for the transmission electron microscope, a bias electrode is deposited on the heating chip at the same time, the bias electrode adopts a four-electrode structure, two electrodes are used to connect current, and two electrodes are used to monitor voltage drop.

In the in-situ electrical sample rod system for the transmission electron microscope, the bias electrode is deposited on the window, and the bias electrode is made of high temperature resistant metal materials: Cr/Au, Ti/Au, Cr/Pt, Ti/Pt, Cr /CuTi/Cu, Cr/Ag or Ti/Ag.

The in-situ electrical sample rod system for the transmission electron microscope can realize the atomic-scale measurement and research of the macroscopic properties of the material under the conditions of heating and powering the external field in the high vacuum of the transmission electron microscope, and the heating temperature range of the miniature sample stage is : Room temperature to 200°C, maximum heating rate ≥ 10°C/s, maximum heating rate of heating chip ≥ 500°C/s, maximum cooling rate ≥ 500°C/s, heating temperature range: room temperature to 1000°C, temperature stability ≤ ± 0.1 ℃, applied bias voltage ≤±30V, current ≤1A.

Advantage of the present invention and beneficial effect are:

1. The present invention mainly includes: a high-vacuum circular airtight connector for conducting electrical signals, a hollow sample rod frame with surface insulation, a wire placed in the sample rod frame, a ceramic heating chip, a thermistor, and a temperature control unit , heating chip, etc., the thermistor and ceramic heating are integrated on the micro-sample stage, connected to the external circuit unit through wires and circular airtight connectors, used to monitor the heating temperature, heating rate and temperature stability of the micro-sample stage, The heating chip is placed on the micro-sample stage, which can further control the temperature of the sample micro-region.

2. Based on the above-mentioned in-situ sample rod structure, the system can realize the atomic-scale measurement and research of the macroscopic properties of materials under the conditions of heating and power-on external field in the high vacuum of the transmission electron microscope. The heating temperature range of the micro-sample stage: room temperature to 200 ℃, maximum heating rate ≥ 10 ℃ / s, maximum heating rate of heating chip ≥ 500 ℃ / s, maximum cooling rate ≥ 500 ℃ / s, heating temperature range: room temperature to 1000 ℃, temperature stability ≤ ± 0.1 ℃, applied bias Voltage ≤±30V, current ≤1A.

3. The ceramic heater and the thermistor of the present invention are combined and integrated on the micro-sample stage, which can accurately control the temperature of the sample at the macro scale.

4. The heating chip on the micro-sample stage of the present invention can accurately monitor the temperature of the micro-zone of the sample in real time, and realize the temperature adjustment function of the sample to the greatest extent.

5. The bias function of the present invention adopts a four-electrode structure, which can accurately measure the electrical signals of samples at different temperatures, is not affected by contact resistance, and has strong anti-interference ability.

6. The effective micro-zone heating area of the present invention is small and concentrated, and the infrared radiation caused by it has little influence on background noise interference of transmission electron microscope EDS analysis, and can accurately analyze the composition of samples above 650°C.

Description of drawings

Fig. 1 Effect diagram of the in-situ electrical sample holder system for transmission electron microscopy.

Fig. 2 The perspective view of the assembly of the miniature sample stage at the front end of the sample rod.

Figure 3 is a stereoscopic schematic diagram of the assembled miniature sample stage.

Fig. 4 is a schematic structural diagram of a heating chip with a bias function.

The reference signs are explained as follows:

1—sample rod frame; 2—high vacuum circular airtight connector that conducts electrical signals; 3—ceramic heating plate; 4—thermistor; 5—metal wire; 6—miniature sample stage; 7—heating chip; 8—window; 9—heating electrode; 10—bias electrode.

Detailed ways

The specific implementation manner of the invention will be described in further detail below in conjunction with the accompanying drawings and embodiments. For the detailed description of these embodiments, it should be understood that those skilled in the art can practice the present invention, and can use other embodiments without departing from the spirit of the appended claims and the scope of the present invention. Modifications and/or changes are made to the examples shown. Furthermore, although specific features of the present invention are disclosed in the embodiments, such specific features can be properly modified to achieve the functions of the present invention.

As shown in Figures 1 to 4, the in-situ electrical sample rod system for a transmission electron microscope of the present invention mainly includes: a hollow sample rod frame 1, a high vacuum circular airtight connector 2 for conducting electrical signals, a ceramic heating plate 3, The thermistor 4, the external circuit unit, the metal wire 5 placed in the frame of the hollow sample rod, the micro sample stage 6, the heating chip 7 and other parts, the specific structure is as follows:

The sample rod frame 1 is a hollow structure, and an insulating coating is deposited on its surface to avoid potential safety hazards caused by the short circuit between the metal wire 5 and the sample rod frame 1. The end of the sample rod frame 1 is connected to the high vacuum circular airtight connector that conducts electrical signals 2 connected, the high-vacuum circular airtight connector 2 that conducts electrical signals isolates the high vacuum inside the sample rod frame 1 from the external atmosphere, and the high-vacuum circular air-tight connector 2 that conducts electrical signals connects the sample rod through a metal wire 5 The ceramic heating chip 3, thermistor 4, heating chip 7 and external circuit unit at the front end of the system. The function of the external circuit unit is to monitor the temperature of the ceramic heating chip, the heating chip, the bias electrode and the current.

As shown in Fig. 2-Fig. 3, the ceramic heater 3 and thermistor 4 are installed on the miniature sample stage 6, and are connected with the external circuit unit through the metal wire 5 and the high-vacuum circular airtight connector 2 that conducts the electric signal, Used to monitor the heating temperature and heating rate of the micro sample stage. The micro-sample stage 6 is made of metal (such as copper-tungsten alloy, etc.), and a 100 μm thick Al ₂ O ₃ insulating layer is deposited on its surface to avoid potential safety hazards caused by short circuits between the heating chip and the sample and the micro-sample stage 6 .

As shown in Figure 4, the heating chip 7 is placed in the micro-sample stage 6, which is used for micro-region temperature regulation, and carries various solid samples at the same time. It is made of aluminum oxide, silicon oxide, silicon nitride or carbide transparent to the electron beam The silicon window 8 is composed of good chemical and physical stability. The heating electrode 9 on the heating chip 7 is deposited on the window 8, and the heating electrode 9 is made of Cr/Au/Al ₂ O ₃ , Ti/Au/Al ₂ O ₃ , Cr/Pt/Al ₂ O ₃ , Ti/Pt/Al ₂ O ₃ , Cr/Cu/Al ₂ O ₃ , Ti/Cu/Al ₂ O ₃ , Cr/Ag/Al ₂ O ₃ or Ti/Ag/Al ₂ O ₃ , Al ₂ O ₃ on the top layer has high thermal conductivity Insulating inert material to avoid reaction of the sample with the window material. The heating electrode 9 adopts a four-electrode structure, two electrodes are used for temperature measurement, and two electrodes are used for heating. The heating wires are wrapped around the window 8 to ensure uniform heating of the sample. Bias electrodes 10 are deposited on the heating chip 7 at the same time, which also adopts a four-electrode structure, two electrodes are used for connecting current, and two electrodes are used for monitoring voltage drop. The bias electrode 10 is deposited on the window 8, using high temperature resistant metal materials, such as: Cr/Au, Ti/Au, Cr/Pt, Ti/Pt, Cr/Cu Ti/Cu, Cr/Ag or Ti/Ag, etc. .

The results of the examples show that the present invention maximizes the atomic-scale measurement and research of the macroscopic properties of materials in a vacuum environment and under heating and external field conditions, and is widely applicable to exploring various high-temperature phase transitions, electrical properties, thermoelectric properties, chemical reaction etc.

The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are only illustrative, rather than restrictive. Under the enlightenment of the invention, without departing from the gist of the invention and the scope of protection of the claims, many forms can also be made, and these all belong to the protection of the present invention.

Claims (8)

1. a kind of transmission electron microscope electricity sample lever system in situ, it is characterised in that：The system includes hollow sample successively Product bar frame (1) conducts the high vacuum circle hermetic connector (2) of electric signal, is ceramic heating flake (3), thermistor (4), outer Portion's circuit unit, the plain conductor (5) being placed in hollow specimen holder frame, minute sample platform (6), heating chip (7), it is specific to tie Structure is as follows：

Specimen holder frame (1) is hollow structure, and surface deposition insulating coating avoids plain conductor therein (5) and specimen holder Frame (1) short circuit generates security risk, the end of specimen holder frame (1) and the high vacuum circle hermetic connector of conduction electric signal (2) be connected, by conducting the high vacuum circle hermetic connector (2) of electric signal, the internal high vacuum of isolation specimen holder frame (1) with Atmosphere outside, the high vacuum circle hermetic connector (2) for conducting electric signal connect sample lever system by plain conductor (5) Ceramic heating flake (3), thermistor (4), heating chip (7) and the external circuit unit of front end；

Ceramic heating flake (3) and thermistor (4) are integrated on minute sample platform (6), pass through plain conductor (5) and conduction telecommunications Number high vacuum circle hermetic connector (2) be connected with external circuit unit, for monitoring to the heating temperature of minute sample platform And the rate of heat addition.

2. transmission electron microscope described in accordance with the claim 1 electricity sample lever system in situ, it is characterised in that：Miniature sample Sample platform (6) is metal material, and surface deposition has 80~120 μ m-thick Al₂O₃Insulating layer, avoid heating chip and sample with it is miniature Sample stage (6) short circuit generates security risk.

3. transmission electron microscope described in accordance with the claim 1 electricity sample lever system in situ, it is characterised in that：Heating core Piece (7) is placed in minute sample platform (6), is regulated and controled for micro-area temperature, while carry various solid samples, heating chip (7) By being formed to the transparent aluminium oxide of transmission electron beam, silica, silicon nitride or silicon carbide window (8), with good chemistry And physical stability.

4. according to the electricity sample lever system in situ of the transmission electron microscope described in claim 1 or 3, it is characterised in that：Add Heating electrode (9) on hot chip (7) is deposited on window (8), and heating electrode (9) is using Cr/Au/Al₂O₃、Ti/Au/ Al₂O₃、Cr/Pt/Al₂O₃、Ti/Pt/Al₂O₃、Cr/Cu/Al₂O₃Ti/Cu/Al₂O₃、Cr/Ag/Al₂O₃Or Ti/Ag/Al₂O₃, heating The Al of electrode (9) top layer₂O₃For high heat conductive insulating inert material, sample is avoided to be reacted with window material.

5. according to the electricity sample lever system in situ of the transmission electron microscope described in claim 4, it is characterised in that：Heating electricity Pole (9) is using four electrode structures, and two path electrodes are used for thermometric, and for two path electrodes for heating, heating wires are surrounded on window (8) four Week, it is ensured that sample homogeneous heating.

6. according to the electricity sample lever system in situ of the transmission electron microscope described in claim 4, it is characterised in that：Heating core Deposition has bias electrode (10) simultaneously on piece (7), and using four electrode structures, two path electrodes are used to connect electricity bias electrode (10) Stream, two path electrodes drop for monitoring voltage.

7. according to the electricity sample lever system in situ of the transmission electron microscope described in claim 6, it is characterised in that：Bias plasma Pole (10) is deposited on window (8), and bias electrode (10) is using refractory metal material：Cr/Au、Ti/Au、Cr/Pt、Ti/Pt、 Cr/Cu Ti/Cu, Cr/Ag or Ti/Ag.

8. according to the electricity sample lever system in situ of the transmission electron microscope described in one of claim 1 to 7, feature exists In：The system can be realized in the case where heating and powering up condition of external field in the high vacuum of transmission electron microscope to the atom of material macro property Scale measures and research, minute sample platform (6) heating temperature range：To 200 DEG C, maximum heating rate >=10 DEG C/sec add room temperature Hot chip (7) maximum heating rate >=500 DEG C/sec, maximum cooling rate >=500 DEG C/sec, heating temperature range：Room temperature is extremely 1000 DEG C, temperature stability≤± 0.1 DEG C is biased≤± 30V, electric current≤1A.