LU502524B1 - A Device and Method for In-situ measurement on Low-Temperature Crystal Structure of Two-Dimensional Materials - Google Patents
A Device and Method for In-situ measurement on Low-Temperature Crystal Structure of Two-Dimensional Materials Download PDFInfo
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- LU502524B1 LU502524B1 LU502524A LU502524A LU502524B1 LU 502524 B1 LU502524 B1 LU 502524B1 LU 502524 A LU502524 A LU 502524A LU 502524 A LU502524 A LU 502524A LU 502524 B1 LU502524 B1 LU 502524B1
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- 239000013078 crystal Substances 0.000 title claims abstract description 49
- 239000000463 material Substances 0.000 title claims abstract description 48
- 238000012625 in-situ measurement Methods 0.000 title claims abstract description 20
- 238000000034 method Methods 0.000 title abstract description 11
- 239000000758 substrate Substances 0.000 claims abstract description 92
- 238000002360 preparation method Methods 0.000 claims abstract description 49
- 238000002128 reflection high energy electron diffraction Methods 0.000 claims abstract 9
- 239000007789 gas Substances 0.000 claims description 33
- 238000005057 refrigeration Methods 0.000 claims description 14
- 239000003507 refrigerant Substances 0.000 claims description 12
- 230000005540 biological transmission Effects 0.000 claims description 11
- 230000001681 protective effect Effects 0.000 claims description 11
- 238000000605 extraction Methods 0.000 claims description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 6
- 229910052802 copper Inorganic materials 0.000 claims description 6
- 239000010949 copper Substances 0.000 claims description 6
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 5
- 238000000427 thin-film deposition Methods 0.000 claims description 5
- 229910000963 austenitic stainless steel Inorganic materials 0.000 claims description 4
- SWQJXJOGLNCZEY-BJUDXGSMSA-N helium-3 atom Chemical compound [3He] SWQJXJOGLNCZEY-BJUDXGSMSA-N 0.000 claims description 4
- 238000005259 measurement Methods 0.000 abstract description 5
- 239000002184 metal Substances 0.000 abstract description 5
- 229910052751 metal Inorganic materials 0.000 abstract description 5
- 238000011065 in-situ storage Methods 0.000 abstract description 4
- 238000002844 melting Methods 0.000 abstract description 3
- 230000008018 melting Effects 0.000 abstract description 2
- 238000005516 engineering process Methods 0.000 description 17
- 239000010408 film Substances 0.000 description 11
- 238000012360 testing method Methods 0.000 description 11
- 238000002441 X-ray diffraction Methods 0.000 description 10
- 238000010894 electron beam technology Methods 0.000 description 10
- 238000004458 analytical method Methods 0.000 description 9
- 239000010409 thin film Substances 0.000 description 8
- 230000008859 change Effects 0.000 description 6
- 238000012512 characterization method Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 238000001179 sorption measurement Methods 0.000 description 4
- 238000012546 transfer Methods 0.000 description 4
- 238000001451 molecular beam epitaxy Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 238000004549 pulsed laser deposition Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- 238000000097 high energy electron diffraction Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000010249 in-situ analysis Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/24—Vacuum evaporation
- C23C14/28—Vacuum evaporation by wave energy or particle radiation
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/52—Means for observation of the coating process
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/54—Controlling or regulating the coating process
- C23C14/541—Heating or cooling of the substrates
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
- C30B25/02—Epitaxial-layer growth
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
- C30B25/02—Epitaxial-layer growth
- C30B25/12—Substrate holders or susceptors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
- G01N23/20008—Constructional details of analysers, e.g. characterised by X-ray source, detector or optical system; Accessories therefor; Preparing specimens therefor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
- G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
- G01N23/20058—Measuring diffraction of electrons, e.g. low energy electron diffraction [LEED] method or reflection high energy electron diffraction [RHEED] method
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- Mechanical Engineering (AREA)
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- Analysing Materials By The Use Of Radiation (AREA)
Abstract
The invention provides a device and a method for in-situ measurement of the low-temperature crystal structure of two-dimensional materials. The device is comprised of a low-temperature control system, a RHEED system, a substrate holder, a substrate holder lifter, a hollow Z-axis drive and a vacuum system. Switch between low-temperature working mode and high- temperature working mode can be realized by adjusting the relative distance between the substrate holder and the heat exchanger. Under the low-temperature working mode, the back of the substrate holder is in contact with the bottom of the heat exchanger, which is suitable for the low-temperature crystal structure measurement of two-dimensional materials and the preparation of metal films with low melting point. Under the high-temperature working mode, the heat exchanger is far away from the substrate holder, and the high vacuum environment ensures the minimal gas convection heat leakage. The invention integrates a low-temperature control system and a RHEED system, thus providing a low-temperature environment for the crystal structure measurement of two-dimensional materials. The invention has the advantages of simplicity in structure, convenience in operation and it is suitable for low-temperature crystal structure measurement of two-dimensional materials which is in situ and nondestructive to samples.
Description
A Device and Method for In-situ measurement on Low-Temperature LUS02524
Crystal Structure of Two-Dimensional Materials
The invention relates to the technical field of spintronics, in particular to a device and a method for in-situ measurement of the low-temperature crystal structure of two-dimensional materials.
With the miniaturization trend of smart phones, notebook computers and other electronic products, traditional electronic devices are faced with many challenges such as increased power consumption and increased manufacturing costs. In recent years, two-dimensional materials with only a few atomic layers show many excellent properties different from traditional bulk materials, and are expected to become the key materials for spintronic devices with small volume and low power consumption. However, many novel physical properties of two-dimensional materials only appear at low temperatures. Considering the important influence of the crystal structure on thematerial properties, it is of great significance to study the crystal structure of two-dimensional materials at different temperatures, especially at low temperatures, in order to understand the relationship between the structure and properties of materials and to explore spintronic devices with excellent properties.
At present, the main techniques to study the crystal structure of materials at low temperature are low-temperature XRD (X-ray diffraction) and low-temperature TEM (transmission electron microscope). Low-temperature XRD uses X-rays as the detection light source and controls the temperature through low-temperature accessories. However, due to the limited intensity of X-rays, XRD is not suitable for crystal structure analysis of two- dimensional materials with only a few atomic layers. TEM uses the transmitted electron beam as the detection light source, and realizes the temperature control through a special low- temperature sample rod. Due to the low penetration power of the electron beam, the observed area of the sample must be thinned below 100nm before it can be used for TEM. The sample preparation process is complicated and time-consuming, and it will cause the deformation and contamination of the sample. Considering that two-dimensional materials are only a few atomic layers thick and have high specific surface area, their surfaces are sensitive to surface adsorption and external environment. However, the measurement of the crystal structures are 1 not carried out in situ for the above-mentioned low-temperature XRD and low-temperature LV502524
TEM, involving a sample transfer from the preparation equipment to the characterization equipment. The inevitable surface adsorption in the process of sample transfer may greatly change the structures and properties of two-dimensional materials. Therefore, the in-situ characterization is very important to obtain the intrinsic structure and properties of two- dimensional materials.
RHEED (Reflective High Energy Electron Diffraction) is a technology that uses the reflection of high-energy electron beam to obtain the surface information of samples (surface sensitivity of 1 ~ 4 nm). Different from XRD, RHEED technology uses high-energy electron beam instead of X-ray as the light source, having intensity high enough to obtain the crystal structure information of two-dimensional materials. Different from TEM, RHEED technology uses the reflection of electron beam instead of the transmission of electron beam to obtain crystal structure information. Therefore, the sample does not need special thinning whereby the nondestructive crystal structure analysis can be realized. Moreover, RHEED is usually set in the thin film deposition system, where the real-time monitor of epitaxial thin film growth and the in-situ crystal structure characterization are realized at the same time. However, the present RHEED technology can only be carried out at and above room temperature, but cannot be used for crystal structure analysis at low temperatures. Therefore, it is urgent to develop a technology of crystal structure characterization at low temperatures, which is suitable for two-dimensional materials, simple and nondestructive to the samples.
In order to solve the above technical problems, the invention discloses a device and a method for in-situ measurement on the low-temperature crystal structure of two-dimensional materials. The technical scheme of the invention is implemented as follows:
A device for in-situ measurement on the low-temperature crystal structure of two- dimensional materials comprises a low-temperature control system, a RHEED system, a substrate holder, a substrate holder lifter, a hollow Z-axis driver and a vacuum system;
Wherein, the low-temperature control system is located on and connected to the vacuum system, the RHEED system is installed at the side of the vacuum system, the substrate holder is installed below the low-temperature control system, the hollow Z-axis driver is located at the junction of the low-temperature control system and the vacuum system and controls the low-temperature control system, and the substrate holder lifter is installed at the upper side of 2 the hollow Z-axis driver and controls the substrate holder; The height of the substrate holder LV502524 can be independently controlled by the substrate holder lifter, so that the relative distance between the substrate holder and the heat exchanger can be adjusted.
The bottom of that substrate holder is provide with a substrate; The substrate holder integrates a temperature feedback control system consisting of a heater, a thermometer and a feedback temperature control element;
The low-temperature control system comprises a closed cycle refrigerator, an air extraction device, an air transmission device, a mass flow controller and a heat exchanger;
The circulate refrigerator is located at that upper part of the low-temperature control system, the air extraction device is connecte with the gas delivery device and located at the side of the closed-cycle refrigerator, the mass flow controller is locate on the connecting pipeline between the gas delivery device and the closed-cycle refrigerator, and the heat exchanger is connected and located below the closed-cycle refrigerator.
Preferably, the vacuum system comprises a vacuum preparation chamber, a vacuum pump and a vacuum interface; The vacuum pump is installed on the lower side wall of the vacuum preparation chamber, the vacuum interface is located at the top of the vacuum preparation chamber, and the heat exchanger extends into the vacuum preparation chamber through the vacuum interface.
Preferably, the RHEED system comprises a RHEED electron gun and a RHEED fluorescent screen, The RHEED electron gun is located at one side of the vacuum preparation chamber, and the RHEED fluorescent screen is located at the other side of the vacuum preparation chamber.
Preferably, the closed cycle refrigerator comprises a refrigeration head, a compressor and a gas conveying pipeline; The refrigeration head extends into the heat exchanger, and the refrigeration head is connected with the compressor through a gas transmission pipeline.
Preferably, the outer surface of the substrate holder is made of oxygen-free copper with high thermal conductivity.
Preferably, the vacuum preparation chamber is a thin film deposition chamber.
Preferably, the heat exchanger is provided with a protective cover; The protective cover wraps the surface of the heat exchanger.
Preferably, the protective cover is made of austenitic stainless steel and has a long tubular structure. 3
Preferably, the types of the closed cycle refrigerator include pulse tube refrigerator and LU502524
Gifford-McMahon refrigerator; The refrigerant gas in the closed cycle refrigerator is selected from one of helium 3 or helium 4.
A method for in-situ measurement of low-temperature crystal structure of two- dimensional materials includes low-temperature working mode and high-temperature working mode.
In a low-temperature working mode, the substrate holder lifter lifts the substrate holder so that the back surface of the substrate holder is completely contacted with the bottom end of the heat exchanger, the mass flow controller accurately controls the balance between the flow rate of refrigerant gas and the heating power of the heater of the substrate holder, and at the same time, the hollow Z-axis driver adjusts the overall height of the substrate holder and the heat exchanger. Such that the electron beam emitted from the RHEED electron gun grazes the substrate surface of the substrate holder, and the electron beam with crystal structure information reflected by the substrate surface appears on the RHEED screen;
In a high-temperature working mode, the substrate holder is lowered by the substrate holder lifter, so that the substrate holder is far away from the heat exchanger; the temperature control is realized by a temperature feedback control system integrated in the substrate holder, so as to meet the requirement of substrate temperature for film preparation; and meanwhile, the overall height of the substrate holder and the heat exchanger is adjusted by the hollow Z- axis driver, so as to meet the requirement of substrate height for film preparation.
The low-temperature control system in the invention provides a low-temperature environment and precise temperature control conditions for the test, and by accurately controlling the flow rate of low-temperature refrigeration gas and the balance of heating power of the substrate heater, the precise control of the substrate temperature and the wide- range temperature change test of the crystal structure of two-dimensional materials are realized, thus solving the problem that the existing RHEED technology cannot test the low- temperature crystal structure;
The RHEED technology in the invention is compatible with many thin film preparation systems such as pulsed laser deposition system and molecular beam epitaxy system, which ensures the in-situ measurement of the crystal structure of two-dimensional materials, thus avoiding the influence of surface adsorption in the sample transfer process involved in other crystal structure analysis technologies including XRD and TEM technologies;
Compared with the traditional low-temperature TEM technology, the low-temperature
RHEED technology of the invention has the advantages of no special sample preparation and 4 nondestructive to samples, and compared with the traditional low-temperature XRD, it has the LV502524 characteristics of high light source intensity and suitability for crystal structure analysis of two-dimensional materials.
The low-temperature control system in the invention not only provides low-temperature test conditions for RHHED system, but also provides low-temperature preparation conditions for film preparation system, expanding the function of film preparation, and is especially suitable for the preparation of low-melting-point metal films.
According to the invention, a set of devices can be used to realize the preparation of two- dimensional materials and the wide-range temperature change test and analysis of crystal structures, and the space utilization rate of the devices is greatly improved.
In order to more clearly explain the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only one embodiment of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to these drawings on the premise of no creative effort.
Fig. 1 is a schematic diagram of the device structure of embodiment 1.
In the above drawings, each figure number indicates: 1. Compressor 2. Pumping equipment 3. Gas transmission equipment 4. Mass flow controller 5. Refrigeration head 6. Heat exchanger 7. Vacuum interface 8. Substrate holder lifter 9. Hollow Z-axis driver 10. RHEED Electron gun 11. RHEED Screen 12. Vacuum pump 13. Vacuum preparation chamber
14. Substrate holder LU502524 15. Substrate
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, but not all of them. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in the field without creative labor are within the scope of the present invention.
In a specific embodiment, as shown in fig. 1, a device for in-situ measurement on the low-temperature crystal structure of two-dimensional materials includes a low-temperature control system, a RHEED system, a substrate holder 14, a substrate holder lifter 8, a hollow
Z-axis driver 9 and a vacuum system;
Wherein, the low-temperature control system is located on and connected to the vacuum system, RHEED system is installed at the side of the vacuum system, substrate holder 14 is installed below the low-temperature control system, hollow Z-axis driver is located at the junction of the low-temperature control system and the vacuum system and controls the low- temperature control system, substrate holder lifter 8 is installed at the upper side of the hollow
Z-axis driver and controls substrate holder 14, and substrate holder 14 can move by controlling the hollow Z-axis driver; The height of the substrate holder 14 can be independently controlled by the substrate holder lifter 8, so that the relative distance between the substrate holder 14 and the heat exchanger 6 can be adjusted.
A substrate 15 is arranged at the bottom of the substrate holder 14; The substrate 15 is adhered to the center of the surface of the substrate holder 14 by an adhesive with good thermal conductivity and high and low temperature resistance. The substrate 14 is integrated with a temperature feedback control system consisting of a heater, a thermometer and a feedback temperature control element;
The low temperature control system comprises a closed cycle refrigerator, an air extraction device 2, an air transmission device 3, a mass flow controller 4 and a heat exchanger 6; The circulating refrigerator is located at the upper part of the low-temperature control system, the pumping equipment 2 is connected with the gas conveying equipment 3 6 and is located at the side of the closed-cycle refrigerator, the mass flow controller 4 is located LU502524 on the connecting pipeline between the gas conveying equipment 3 and the closed-cycle refrigerator, and the heat exchanger 6 is connected and located below the closed-cycle refrigerator.
The vacuum system comprises a vacuum preparation chamber 13, a vacuum pump 12 and a vacuum interface 7; The vacuum pump 12 is installed on the lower side wall of the vacuum preparation chamber 13 to evacuate the vacuum preparation chamber 13, the vacuum interface 7 is located at the top of the vacuum preparation chamber 13, and the heat exchanger 6 extends into the vacuum preparation chamber 13 through the vacuum interface 7 to refrigerate the sample.
RHEED system includes RHEED electron gun 10 and RHEED fluorescent screen 11;
RHEED electron gun 10 is located at one side of vacuum preparation chamber 13, and
RHEED fluorescent screen 11 is located at the other side of vacuum preparation chamber 13, which is used for real-time monitoring and in-situ analysis of crystal structure during film growth.
The closed cycle refrigerator comprises a refrigeration head 5, a compressor 1 and a gas conveying pipeline; The refrigeration head 5 extends into the heat exchanger 6, and the refrigeration head 5 is connected with the compressor 1 through a gas transmission pipeline.
In this embodiment, the gas transmission equipment 3, the mass flow controller 4, the heat exchanger 6, and the gas extraction equipment 2 are connected in sequence through the gas transmission pipeline. The gas delivery device 3 delivers the refrigerant gas into the pipeline. The mass controller 4 is used to accurately control the flow rate of refrigerant gas.
The heat exchanger 6 can be further cooled by filling refrigerant gas as cooling medium, or by setting throttle valve and liquid helium pool inside. The air extraction device 2 is used to provide a pipeline low-pressure environment for continuous refrigeration. Other low temperature control techniques in the field can also be used to achieve similar effects.
The working modes of this embodiment include a low-temperature working mode and a high-temperature working mode;
The low-temperature mode is used for in-situ measurement of the crystal structure of two-dimensional materials at low temperature, and can also be used for preparing low-melting metal films requiring low-temperature conditions. In this mode, the temperature of the substrate holder 14 is lower than room temperature; The second is the high-temperature working mode, which is usually the mode of the thin film preparation system. In this mode, the temperature of the substrate holder 14 is higher than or equal to room temperature. 7
In the low-temperature mode, the substrate holder 14 is lifted by the substrate holder LU502524 lifter 8, so that the back surface of the substrate holder 14 is completely contacted with the bottom end of the heat exchanger 6 to realize heat conduction, and the mass flow controller 4 accurately controls the flow rate of refrigerant gas and the balance of heating power of the heater of the substrate holder 14, thus realizing the precise control of the temperature of the substrate holder 14. At the same time, the whole height of the substrate holder 14 and the heat exchanger 6 is adjusted by the hollow Z-axis driver 9, so that the electron beam emitted by the
RHEED electron gun 10 can graze the surface of the substrate 15, and the electron beam with crystal structure information reflected by the surface of the substrate 15 appears on the
RHEED screen 11.
In the high-temperature operation mode, the substrate holder 14 is lowered by the substrate holder lifter 8, so that the substrate holder 14 is far away from the heat exchanger 6 to reduce the heat radiation of the substrate holder 14. At the same time, the high vacuum environment ensures minimal gas convection heat leakage. A temperature feedback control system integrated in the substrate stage 14 is used to control the temperature of the high- temperature zone, so as to meet the requirements of the substrate 15 for the preparation of thin films. In the high-temperature working mode of the present invention, the specific maximum temperature that can be reached depends on the substrate holder 14 of the thin film preparation system itself.
In a preferred embodiment, the outer surface of the substrate holder 14 is made of oxygen-free copper with high thermal conductivity.
In this embodiment, in order to achieve good heat conduction between the substrate holder 14 and the bottom of the heat exchanger 6, and to ensure uniform temperature in the sample area, the outer surface of the substrate holder 14 is made of oxygen-free copper with high thermal conductivity. Of course, this patent is not limited to oxygen-free copper with high thermal conductivity, and other materials with excellent thermal conductivity can also be made, which can be replaced after comprehensive consideration of economy, raw material acquisition and other aspects.
In a preferred embodiment, the vacuum preparation chamber 13 is a thin film deposition chamber.
In this embodiment, the vacuum preparation chamber 13 can be a thin film deposition chamber of a pulsed laser deposition system, a molecular beam epitaxy system or other thin film preparation systems compatible with RHEED system. The substrate holder 14 provided 8 in the thin film preparation system can usually realize the control from room temperature to LV502524 high temperature.
In a preferred embodiment, the heat exchanger 6 is provided with a protective cover; The shield covers the surface of the heat exchanger 6. The protective cover is made of austenitic stainless steel and has a long tubular structure.
In this embodiment, the heat exchanger 6 isolates its internal low-temperature environment from the vacuum environment by a protective cover. The protective cover can be made of common materials suitable for vacuum sealing, such as austenitic stainless steel but not limited to this material. The shape and structure of the protective cover is generally long and tubular, so it is convenient to go deep into the vacuum chamber to refrigerate the sample.
In a preferred embodiment, the types of closed cycle refrigerators include pulse tube refrigerators and Gifford-McMahon refrigerators, The refrigerant gas in the closed cycle refrigerator is selected from one of Helium 3 or Helium 4.
In this embodiment, the types of closed cycle refrigerators include pulse tube refrigerators, Gifford-McMahon refrigerators, and improved refrigerators based on these principles. Of course, a more suitable refrigerator can be selected according to actual needs, as long as it can meet the required requirements. The refrigerant gas may be Helium 3, Helium 4 or other refrigerant gases. The choice of refrigerator model and refrigerant gas depends on the specific refrigeration requirements.
The low-temperature control system of this embodiment provides a low-temperature environment and precise temperature control conditions for the test. By accurately controlling the flow rate of low-temperature refrigeration gas and the balance of heating power of the heater of the substrate holder 14, the precise control of the temperature of the substrate holder 14 and the wide-range temperature change test of the crystal structure of two-dimensional materials are realized, and the problem that the existing RHEED technology cannot test the low-temperature crystal structure is solved.
In this embodiment, the outer surface of the substrate holder 14 is made of oxygen-free copper with high thermal conductivity or other materials with excellent thermal conductivity to ensure the good thermal conductivity at the bottom of the substrate holder 14 and the heat exchanger 6 of the low-temperature control system and the uniform temperature of the sample area. At the same time, the temperature of the substrate holder 14 can be accurately controlled by accurately controlling the flow rate of refrigerant gas and the balance of heater power of the substrate holder 14, thus realizing the wide-range temperature change test of the crystal structure of two-dimensional materials. 9
The substrate holder lifter 8 of this embodiment can independently control the height of LU502524 the substrate holder 14, and can switch between low-temperature and high-temperature working modes by adjusting the relative distance between the substrate holder 14 and the heat exchanger 6. In the low-temperature working mode, the back of the substrate holder 14 is completely in contact with the bottom of the heat exchanger 6, which is suitable for the low- temperature crystal structure measurement of two-dimensional materials and the preparation of low-melting-point metal films. In the high-temperature working mode, the heat exchanger 6 is far away from the substrate holder 14, and the high vacuum environment ensures minimal gas convection heat leakage.
The RHEED technology in the invention is compatible with many thin film preparation systems such as pulsed laser deposition system and molecular beam epitaxy system, ensuring the in-situ measurement of the crystal structure of two-dimensional materials, thus avoiding the influence of surface adsorption in the sample transfer process involved in other crystal structure analysis technologies including XRD and TEM technologies;
Compared with the traditional low-temperature TEM technology, the low-temperature
RHEED technology of this embodiment has the advantages of no special sample preparation and nondestructive to samples, and compared with the traditional low-temperature XRD, it has the characteristics of high light source intensity and suitability for crystal structure analysis of two-dimensional materials.
The low-temperature control system of this embodiment not only provides low- temperature test conditions for RHHED system, but also provides low-temperature preparation conditions for film preparation system, expanding the function of film preparation, and is especially suitable for the preparation of low melting point metal films.
According to the embodiment, a set of devices can be used to realize the preparation of two-dimensional materials and the wide-range temperature change test and analysis of crystal structures, thus greatly improving the space utilization rate of the devices. It should be pointed out that the above description is only a preferred embodiment of the present invention, and it is not intended to limit the present invention. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.
Claims (9)
1. A device for in-situ measurement on the low-temperature crystal structure of two- LV502524 dimensional materials is characterized by comprising a low-temperature control system, a RHEED system, a substrate holder, a substrate holder lifter, a hollow Z-axis driver and a vacuum system; Wherein, the low-temperature control system is located on and connected to the vacuum system, the RHEED system is installed at the side of the vacuum system, the substrate holder is installed below the low-temperature control system, the hollow Z-axis driver is located at the junction of the low-temperature control system and the vacuum system and controls the low-temperature control system, and the substrate holder lifter is installed at the upper side of the hollow Z-axis driver and controls the substrate holder; The bottom of that substrate holder is provide with a substrate; The substrate holder integrates a temperature feedback control system consisting of a heater, a thermometer and a feedback temperature control element; The low-temperature control system comprises a closed cycle refrigerator, an air extraction device, an air transmission device, a mass flow controller and a heat exchanger; The circulate refrigerator is located at that upper part of the low-temperature control system, the air extraction device is connected with the gas delivery device and located at the side of the closed-cycle refrigerator, the mass flow controller is locate on the connecting pipeline between the gas delivery device and the closed-cycle refrigerator, and the heat exchanger is connected and located below the closed-cycle refrigerator.
2. A device for in-situ measurement the low-temperature crystal structure of two- dimensional materials according to claim 1, characterized in that the vacuum system comprises a vacuum preparation chamber, a vacuum pump and a vacuum interface; The vacuum pump is installed on the lower side wall of the vacuum preparation chamber, the vacuum interface is located at the top of the vacuum preparation chamber, and the heat exchanger extends into the vacuum preparation chamber through the vacuum interface.
3. A device for in-situ measurement of low-temperature crystal structure of two- dimensional materials according to claim 2 is characterized in that the RHEED system comprises a RHEED electron gun and a RHEED fluorescent screen, The RHEED electron gun is located at one side of the vacuum preparation chamber, and the RHEED fluorescent screen is located at the other side of the vacuum preparation chamber.
4. A device for in-situ measurement on the low-temperature crystal structure of two- dimensional materials according to claim 3 is characterized in that the closed cycle refrigerator comprises a refrigeration head, a compressor and a gas conveying pipeline; 11
The refrigeration head extends into the heat exchanger, and the refrigeration head is LUV502524 connected with the compressor through a gas transmission pipeline.
5. A device for in-situ measurement of low-temperature crystal structure of two- dimensional materials according to claim 4 is characterized in that the outer surface of the substrate holder is made of oxygen-free copper with high thermal conductivity.
6. A device for in-situ measurement of low-temperature crystal structure of two- dimensional materials according to claim 5 is characterized in that the vacuum preparation chamber is a thin film deposition chamber.
7. A device for in-situ measurement of low-temperature crystal structure of two- dimensional materials according to claim 6 is characterized in that the heat exchanger is provided with a protective cover; The protective cover wraps the surface of the heat exchanger.
8. A device for in-situ measurement on low-temperature crystal structure of two- dimensional materials according to claim 7 is characterized in that the protective cover is made of austenitic stainless steel and has a long tubular structure.
9. A device for in-situ measurement on the low-temperature crystal structure of two- dimensional materials according to claim 8, characterized in that the types of closed-cycle refrigerators include pulse tube refrigerators and Gifford-McMahon refrigerators; The refrigerant gas in the closed cycle refrigerator is selected from one of helium 3 or helium 4. 12
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| LU502524A LU502524B1 (en) | 2022-07-19 | 2022-07-19 | A Device and Method for In-situ measurement on Low-Temperature Crystal Structure of Two-Dimensional Materials |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| LU502524A LU502524B1 (en) | 2022-07-19 | 2022-07-19 | A Device and Method for In-situ measurement on Low-Temperature Crystal Structure of Two-Dimensional Materials |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| LU502524B1 true LU502524B1 (en) | 2024-01-22 |
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ID=89720114
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| LU502524A LU502524B1 (en) | 2022-07-19 | 2022-07-19 | A Device and Method for In-situ measurement on Low-Temperature Crystal Structure of Two-Dimensional Materials |
Country Status (1)
| Country | Link |
|---|---|
| LU (1) | LU502524B1 (en) |
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2022
- 2022-07-19 LU LU502524A patent/LU502524B1/en active
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