Integrated molecular beam epitaxy device and method of using the same

Abstract

The present invention discloses an integrated molecular beam epitaxy device and a method for using the same, including a growth chamber and a sample transfer chamber, a plug valve for controlling the connection and isolation between the growth chamber and the sample transfer chamber is installed between the growth chamber and the sample transfer chamber, the growth chamber and the sample transfer chamber are both arranged on a support frame, a vacuum pumping system is installed on the growth chamber and the sample transfer chamber, the growth chamber includes a deposition chamber, an evaporation source and an electron gun are respectively installed on the deposition chamber, and the deposition chamber is configured to be superimposed and / or alternately used to evaporate and coat a substrate located in the deposition chamber. The present invention has a simple structure, and by adding another evaporation device, an electron gun, and combining it with the evaporation source, by superimposing or alternating the two devices, the combination of the electron gun and the evaporation source provides researchers with greater flexibility, and the most suitable evaporation method can be selected according to different needs. By accurately controlling the working mode of the electron gun and the evaporation source, the growth process of the film can be more finely regulated, thereby improving the quality of the film.

Description

Technical Field

[0001] The invention relates to the technical field of thin film deposition, in particular to an integrated molecular beam epitaxy device and a use method thereof. Background Art

[0002] Molecular beam epitaxy is an advanced thin film growth process that precisely controls the molecular beam or atomic beam generated by evaporation of source materials under ultra-high vacuum conditions and deposits them layer by layer on a single crystal substrate to achieve the growth of high-quality single crystal thin films. This technology can provide sub-monoatomic layer precision growth, thereby precisely controlling the thickness, composition and structure of the film, and occupies an important position in materials science and the semiconductor industry.

[0003] However, despite the above advantages of MBE technology, it still faces the following significant challenges in practical applications:

[0004] High cost: The manufacturing of MBE equipment requires complex vacuum systems, precision mechanical components, high-precision control systems, and special materials, which lead to huge initial investment in the equipment. In addition, in order to ensure the stable operation of the equipment under high vacuum and precise control conditions, regular maintenance and calibration are required, which further increases the long-term operating costs. This makes MBE technology difficult to promote in cost-sensitive application fields.

[0005] Complexity of operation and maintenance: The operation of MBE equipment requires highly specialized knowledge and skills, including but not limited to vacuum technology, material science, and semiconductor technology. At the same time, the maintenance of the equipment must also strictly follow the operating procedures, which places high demands on the professional level of the technicians. This complexity not only increases the difficulty of use, but may also lead to failures caused by improper operation or untimely maintenance, affecting production efficiency and product quality.

[0006] Low growth rate: MBE adopts a layer-by-layer growth method. Its inherent low growth rate (usually about 1μm / h or even lower) limits the application potential of this technology in large-scale production and cannot meet some scenarios with high requirements for production speed.

[0007] In view of the above problems existing in the existing MBE technology, the present invention proposes an integrated molecular beam epitaxy device and a method for using the same. Summary of the invention

[0008] The object of the present invention is to provide an integrated molecular beam epitaxy device and a method of using the same to solve the problems raised in the above background technology.

[0009] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an integrated molecular beam epitaxy device, comprising a growth chamber and a sample transfer chamber, a gate valve for controlling the connection and isolation between the growth chamber and the sample transfer chamber is installed between the growth chamber and the sample transfer chamber, the growth chamber and the sample transfer chamber are both arranged on a support frame, and a vacuum pumping system is installed on the growth chamber and the sample transfer chamber, the growth chamber comprises a deposition chamber, an evaporation source and an electron gun are respectively installed on the deposition chamber, and are configured to be superimposed and / or alternately used to evaporate and coat a substrate located in the deposition chamber, and a sample stage is installed on the deposition chamber to provide support and heating for the substrate located in the deposition chamber.

[0010] As a further solution of the present invention: a cold trap located in the deposition chamber is provided on the sample stage, the cold trap includes an independent upper cold trap chamber and a lower cold trap chamber, the upper cold trap chamber and the lower cold trap chamber both adopt a hollow-out design in the middle, the upper cold trap chamber and the lower cold trap chamber are connected by a plurality of support rods for balancing the supporting force, the upper cold trap chamber is provided with a liquid nitrogen inlet and a liquid nitrogen outlet, and two fluid pipes connecting the upper cold trap chamber and the lower cold trap chamber are provided between the upper cold trap chamber and the lower cold trap chamber for realizing the circulation of liquid nitrogen in the upper cold trap chamber and the lower cold trap chamber.

[0011] As a further solution of the present invention: a chamber cover is provided above the deposition chamber, and a baffle assembly and a hydraulic feedthrough are respectively installed on the chamber cover. The number of the hydraulic feedthroughs is two, and the two hydraulic feedthroughs are respectively connected to the liquid nitrogen inlet and the liquid nitrogen outlet.

[0012] As a further solution of the present invention: the deposition chamber is equipped with a film thickness meter, a RHEED high energy reflection electron diffractometer, a fluorescent screen, a vacuum gauge, an observation window and an ion gauge.

[0013] As a further solution of the present invention: the vacuum pumping system includes two molecular pumps, and the two molecular pumps are respectively connected to the inside of the growth chamber and the sample transfer chamber, wherein a compound pump is also installed on the growth chamber.

[0014] As a further solution of the present invention: the sample stage comprises:

[0015] A substrate stage, used for carrying a substrate to be processed;

[0016] A hollow magnetic coupling is arranged above the substrate stage to drive the substrate stage to rotate;

[0017] A linear drive assembly is used to control the lifting movement of the substrate stage; the linear drive is connected to a flange, and a connecting pipe connected to a heater is installed on the flange. The heater is powered by a heating power feedthrough and is connected to a thermocouple to achieve temperature monitoring and control.

[0018] As a further solution of the present invention: a sample rack is provided inside the cavity of the sample transfer chamber for placing the wafer to be tested. The sample rack is equipped with a rotating lifting assembly that can accurately adjust and position the wafer. A sample transfer rod is also installed on the sample transfer chamber for performing automated transportation and retrieval tasks of the wafer.

[0019] A method for using an integrated molecular beam epitaxy device comprises the following steps:

[0020] S1: Place the wafer to be prepared on the sample holder, and add corresponding evaporation materials to the evaporation source and electron gun respectively according to the characteristics of the film to be prepared. Then start the vacuum system to make the vacuum degree in the growth chamber and the sample transfer chamber reach the preset requirements, and open the gate valve to prepare for sample transfer;

[0021] S2: Start the sample transfer rod, extend it and send the wafer on the sample holder to the substrate table in the growth chamber. After the wafer is stable, retract the sample transfer rod into the sample transfer chamber and close the gate valve to isolate the growth chamber and the sample transfer chamber.

[0022] S3: adjusting the position of the substrate stage and turning on the hollow magnetic coupling device to make the substrate stage start to rotate;

[0023] S4: heating the evaporation source and the electron gun so that the internal temperature reaches the melting temperature of the evaporation material and remains stable. Then, according to the actual situation, the evaporation source and the electron gun are used in a superimposed or alternating manner to perform evaporation treatment on the wafer.

[0024] S5: After the wafer evaporation is completed, the hollow magnetic coupling, evaporation source and electron gun are turned off in sequence, and the cold trap is kept working to allow the equipment to cool down naturally to room temperature. After the temperature stabilizes, the wafer sample is taken out.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. This application adds another evaporation device, an electron gun, and uses it in combination with an evaporation source. By superimposing or alternating the two devices, the combination of the electron gun and the evaporation source provides researchers with greater flexibility, and they can choose the most suitable evaporation method according to different needs. By precisely controlling the working modes of the electron gun and the evaporation source (such as superposition or alternation), the growth process of the film can be more finely regulated, thereby improving the quality of the film.

[0027] 2. The cold trap device configured in the growth chamber of the present application realizes the circulation and cooling function of liquid nitrogen. By simplifying the structural design of the cold trap and hollowing out the middle, interference with external detection and observation components is avoided, and this design further reduces the manufacturing cost. This design does not occupy the internal space of the chamber, and provides a larger surface area for contact with liquid nitrogen, making the vacuum degree in the chamber lower, which is equivalent to achieving some effects of a cryopump. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0029] Figure 2 is a schematic diagram of the internal structure of the growth chamber of the present invention;

[0030] Figure 3 is an external schematic diagram of a growth chamber of the present invention;

[0031] Figure 4 is a schematic diagram of a linear drive assembly of the present invention;

[0032] Figure 5 It is a cross-sectional schematic diagram of a sample stage of the present invention;

[0033] Figure 6 It is a schematic diagram of a cold trap of the present invention;

[0034] Figure 7 It is a schematic diagram of the sample transfer chamber of the present invention;

[0035] Figure 8 is a schematic diagram of a sample holder of the present invention;

[0036] In the figure: 1. Growth chamber; 11. Deposition chamber; 12. Evaporation source; 13. Electron gun; 14. Sample stage; 141. Substrate stage; 142. Hollow magnetic coupling; 143. Linear drive assembly; 144. Flange; 145. Heater; 146. Connecting pipe; 147. Heating power feedthrough; 148. Thermocouple; 15. Cold trap; 151. Cold trap upper chamber; 152. Cold trap lower chamber; 153. Support rod; 154. Liquid nitrogen inlet; 155. Liquid nitrogen outlet; 156. Fluid tube; 16. Baffle assembly; 17. Hydraulic feedthrough; 2. Sample transfer chamber; 21. Sample rack; 22. Rotating lifting assembly; 23. Sample transfer rod; 3. Gate valve; 4. Support frame; 5. Vacuum system. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] See also Figure 1-8In an embodiment of the present invention, an integrated molecular beam epitaxy device includes a growth chamber 1 and a sample transfer chamber 2, wherein the growth chamber 1 is a chamber for realizing thin film deposition, a gate valve 3 for controlling the connection and isolation between the growth chamber 1 and the sample transfer chamber 2 is installed between the growth chamber 1 and the sample transfer chamber 2, the growth chamber 1 is connected to the gate valve 3 through an internal welding flange, and the gate valve 3 is connected to the sample transfer chamber 2 through a loose flange on the side away from the growth chamber 1, wherein the growth chamber 1 and the sample transfer chamber 2 are both arranged on a support frame 4, and the support frame 4 is relied on to realize the function of stabilizing and transporting the growth chamber 1 and the sample transfer chamber 2, and a vacuum system 5 is installed on the growth chamber 1 and the sample transfer chamber 2, and the vacuum system 5 includes a mechanical pump and a molecular pump, and the mechanical pump and the molecular pump are both provided on the growth chamber 1 and the sample transfer chamber 2, wherein a compound pump is also installed on the growth chamber 1, and the vacuum degree of the growth chamber 1 and the sample transfer chamber 2 is first evacuated to below 50Pa by turning on the mechanical pump, and then the molecular pump is turned on. The sub-pump evacuates the growth chamber 1 and the sample transfer chamber 2, and starts the ion pump in the compound pump and sets the ignition cycle of the titanium sublimation pump in the compound pump to ensure that the vacuum degree of the two chambers meets the operating requirements. An extremely high vacuum environment is achieved by equipping a mechanical pump, a molecular pump and a compound pump to meet the vacuum degree required for high-precision evaporation coating. The vacuum degree of the system can reach 1X10-10mbar. In this embodiment, the vacuum degree of the growth chamber 1 is 1X10-10mbar, and the vacuum degree of the sample transfer chamber 2 is 1X10-8mbar; the growth chamber 1 includes a deposition chamber 11, on which an evaporation source 12 and an electron gun 13 are respectively installed, and are configured to be superimposed and / or alternately used to evaporate and coat the substrate located in the deposition chamber 11, and a sample stage 14 is installed on the deposition chamber 11 for providing support and heating for the substrate located in the deposition chamber 11.

[0039] Specifically, there are multiple evaporation sources 12, and the multiple evaporation sources 12 are all installed obliquely on the deposition chamber 11. In the present embodiment, preferably, the oblique installation angle of the evaporation source 12 is 30° relative to the end face of the observation window, and when the straight-line distance between the crucible of the evaporation source 12 and the wafer surface on the sample stage 14 is 280 mm, the number of evaporation sources 12 used is 6, which can ensure the deposition rate of the thin film, and the electron gun 13 has multiple crucibles, which can be equipped with a variety of different evaporation materials, and melt one material each time evaporation occurs. A crucible in use is located at the center of the electron gun 13, and is placed vertically relative to the sample stage 14, that is, the material can be evaporated vertically upward, which greatly improves the deposition rate.

[0040] In order to optimize the performance and efficiency of the molecular beam epitaxy (MBE) device, increasing the number of evaporation sources 12 or electron guns 13 is considered, but this solution faces significant technical and economic challenges.

[0041] Specifically: the deposition chamber 11 is currently not capable of installing a double evaporation source 12 or a double electron gun 13. To adapt the deposition chamber 11 to this configuration, large-scale design modifications and structural adjustments are required. These modifications are not only complex, but will also significantly increase the manufacturing cost of the device, thereby weakening its economic feasibility; and the heating temperature rise limit of the evaporation source 12 is much lower than that of the electron gun 13, which means that the evaporation source 12 can process a limited number of materials. In particular, when faced with materials that require higher temperatures to evaporate, the evaporation source 12 may not be able to reach the required temperature conditions. In contrast, the electron gun 13 has a higher heating temperature rise capability and can support a wider range of evaporation materials, including those that require higher temperatures to evaporate effectively. In comparison, the combination of the electron gun 13 and the evaporation source 12 can achieve better results; by combining the advantages of the two, a wider range of choices and better deposition control can be provided without significantly increasing system complexity and cost.

[0042] During use, it should be noted that the melting point of the material used to make the crucible in the evaporation source 12 and the electron gun 13 must be much higher than the evaporation material, and the material used for the crucible cannot produce a chemical reaction with the evaporation material.

[0043] In this embodiment, the material used for the crucible is aluminum oxide. Cobalt material is placed in the crucibles of the evaporation source 12 and the electron gun 13 as the evaporation material. In order to perform evaporation deposition, the controllers of the evaporation source 12 and the electron gun 13 are used to heat and raise the temperature of their respective crucibles. Before starting evaporation, it is necessary to ensure that the baffles of the evaporation source 12 and the electron gun 13 are in a closed state to prevent the evaporation material from being deposited on the wafer too early. When the temperature reaches the melting point of the cobalt material, observe through the observation window whether the evaporation source 12 and the electron gun 13 emit obvious red light. If obvious red light is observed, it means that the cobalt material has reached the melting point and is in a sublimation state. After the temperature stabilizes for a period of time, the baffles of the evaporation source 12 and the electron gun 13 are opened, and the wafer is evaporated by overlapping use. This overlapping use method is intended to accelerate the film deposition rate and improve the uniformity of the film. However, during the co-evaporation process, the evaporation source 12 and the electron gun 13 will generate a large amount of thermal radiation in the deposition chamber 11. This may interfere with the diffusion of the evaporated material and affect the thin film deposition. In order to obtain better thin film uniformity and a faster deposition rate, we can adopt an alternating operation mode: first, heat up the evaporation source 12. When it is observed that the crucible has obvious brightness and the temperature is stable, open the baffle to deposit the thin film. After the deposition reaches the target time, close the baffle and perform gradient cooling to prevent the crucible from breaking due to excessive cooling. When the temperature of the evaporation source 12 drops to room temperature, control the electron gun 13 to start heating. When obvious brightness appears and the temperature is stable, open the baffle to perform evaporation. Through this alternating mode, we have successfully improved the uniformity of thin film deposition to 1% and maintained a faster deposition rate. The above-mentioned superimposed and alternating methods can improve the uniformity of the thin film. When alternating, it is recommended to use the evaporation source 12 first. This is because the electron gun 13 is placed vertically under the sample stage 14. Using the electron gun 13 later can further improve the uniformity of the thin film.

[0044] In addition, it is also applicable to the case of evaporating different materials. For example, arsenic material can be added to the electron gun 13, and gallium material can be added to the evaporation source 12. The controller heats up and melts these materials. When the crucible is observed to glow and the temperature is stable, the baffle is opened to deposit a gallium arsenide film on the surface of the wafer. This film is usually used in the semiconductor industry and can meet the heating treatment requirements of evaporation materials with different melting points.

[0045] See also Figure 2-6In one embodiment, in this embodiment, preferably, a cold trap 15 located in the deposition chamber 11 is provided on the sample stage 14, and liquid nitrogen is filled into the cold trap 2 to control the temperature of the substrate stage 141 in the chamber to improve the efficiency and quality of thin film deposition. The cold trap 15 includes an independent upper cold trap chamber 151 and a lower cold trap chamber 152. The upper cold trap chamber 151 and the lower cold trap chamber 152 are both hollowed out in the middle, wherein the upper cold trap chamber 151 is fixedly connected to the sample stage 14 and is installed in the deposition chamber 11 together with the sample stage 14. A chamber cover is provided above the deposition chamber 11. The chamber cover is respectively provided with a baffle assembly 16 and a hydraulic feedthrough 17. There are two hydraulic feedthroughs 17, which are respectively connected to the liquid nitrogen inlet 154 and the liquid nitrogen outlet 155. The upper chamber 151 of the cold trap is connected to the lower chamber 152 of the cold trap by a plurality of support rods 153 for balancing the support force. The upper chamber 151 of the cold trap is provided with a liquid nitrogen inlet 154 and a liquid nitrogen outlet 155. The liquid nitrogen inlet 154 and the liquid nitrogen outlet 155 do not distinguish between the inlet and the outlet, which facilitates the subsequent setting of the liquid nitrogen circulation line in the cold trap 15. The cavity of the upper chamber 151 of the cold trap is divided into an inlet and an outlet by two closing plates. The liquid nitrogen area and the liquid nitrogen discharge area are connected, and the liquid nitrogen inlet 154 and the liquid nitrogen outlet 155 are connected to the liquid nitrogen inlet area and the liquid nitrogen discharge area respectively. Therefore, after the liquid nitrogen enters the liquid nitrogen inlet area of ​​the cold trap upper chamber 151, it will not be directly discharged into the liquid nitrogen discharge area, but will enter the interior of the cold trap lower chamber 152 through the fluid pipe 156 below the liquid nitrogen inlet area. When the cold trap lower chamber 152 is full, it will enter the liquid nitrogen discharge area through the fluid pipe 156 below the liquid nitrogen discharge area, and then be discharged through the liquid nitrogen outlet 155. There are also two connecting cold trap upper chamber 151 and cold trap lower chamber 152. The fluid tube 156 of 152 is used to realize the circulation of liquid nitrogen in the upper chamber 151 and the lower chamber 152 of the cold trap, which realizes the circulation and cooling function of the liquid nitrogen while simplifying the structural design of the cold trap 15. The hollow position in the middle avoids interference with external detection and observation components. This design further reduces the manufacturing cost. In addition, this design does not occupy the internal space of the deposition chamber 11, and provides a larger surface area for contact with liquid nitrogen, so that the vacuum degree in the deposition chamber 11 becomes lower, which is equivalent to realizing part of the effect of the cryopump and reducing the cost of subsequent use.

[0046] See also Figure 2-5In one embodiment, in this embodiment, preferably, the deposition chamber 11 is respectively equipped with a film thickness meter, a RHEED high energy reflection electron diffractometer, a fluorescent screen, a vacuum gauge, an observation window and an ion gauge. Furthermore, the deposition rate of the thin film is measured by the quartz crystal oscillator module of the film thickness meter, and the crystal phase and other parameters of the thin film are monitored by the RHEED high energy reflection electron diffractometer. The laser is emitted by the RHEED electron gun, which is refracted by the wafer and incident on the fluorescent screen. A RHEED analysis instrument is connected outside the fluorescent screen, and the film deposition effect is judged by analyzing the dot matrix. In addition, the film deposition action and environment inside the deposition chamber 11 can be monitored under the action of the observation window.

[0047] See also Figure 4-5 In one embodiment, in this embodiment, preferably, the sample stage 14 includes:

[0048] A substrate stage 141, used for carrying a substrate to be processed;

[0049] The hollow magnetic coupler 142 is disposed above the substrate stage 141 to drive the substrate stage 141 to rotate, so as to improve the uniformity of thin film deposition;

[0050] A linear drive assembly 143 is used to control the lifting movement of the substrate stage 141 to adjust the loading position of the substrate stage 141 and the height from the heater 145;

[0051] The linear drive assembly 143 is connected to a flange 144 on which is mounted a connecting pipe 146 connected to a heater 145 , which is powered by a heating power feedthrough 147 and connected to a thermocouple 148 for temperature monitoring and control.

[0052] In the past, the sample stage of this type of molecular beam epitaxy equipment required two sets of linear lifting devices, one set for controlling the distance between the heater 145 and the substrate stage 141, and the other set for controlling the position of the wafer picking up and placing the sample. In this embodiment, the position of the heater is fixed and only the position of the substrate stage 141 is moved, that is, only one set of linear drive components 143 is needed, which greatly optimizes the sample stage structure and reduces the manufacturing cost.

[0053] In order to ensure the consistency of film deposition conditions, the vertical angle between the evaporation source 12 and the substrate stage 141 remains fixed during the film deposition process. In this embodiment, the angle is set to 30° as a unified benchmark for all film depositions.

[0054] In a conventional dual lift system, the heater 145 and the substrate stage 141 would move simultaneously to achieve the desired angle, however, in this embodiment, since the heater 145 is connected to the flange 144 via a hollow tube, and the flange 144 is fixed to the linear drive assembly 143, this means that the height position of the flange 144 is fixed, and thus the position of the heater 145 also remains unchanged.

[0055] Therefore, when the angle between the evaporation source 12 and the substrate stage 141 needs to be adjusted, only the substrate stage 141 needs to be moved. Specifically, when the linear drive assembly 143 is controlled to lower the substrate stage 141, the wafer sampling or placement work can be performed safely. After completing these actions, the linear drive assembly 143 is controlled again to raise the substrate stage 141 to the exact angle position (e.g., 30°) originally set with the evaporation source 12 to continue the thin film deposition process.

[0056] See also Figure 1 In one embodiment, in this embodiment, preferably, a sample rack 21 is provided inside the cavity of the sample transfer chamber 2 for placing the wafer to be tested. The sample rack 21 is equipped with a rotating lifting assembly 22, which can accurately adjust and position the wafer. A sample transfer rod 23 is also installed on the sample transfer chamber 2 for performing automated transportation and retrieval tasks of the wafer.

[0057] A method for using an integrated molecular beam epitaxy device comprises the following steps:

[0058] S1: Place the wafer to be prepared on the sample holder, and add corresponding evaporation materials to the evaporation source and electron gun respectively according to the characteristics of the film to be prepared. Then start the vacuum system to make the vacuum degree in the growth chamber and the sample transfer chamber reach the preset requirements, and open the gate valve to prepare for sample transfer;

[0059] S2: Start the sample transfer rod, extend it and send the wafer on the sample holder to the substrate table in the growth chamber. After the wafer is stable, retract the sample transfer rod into the sample transfer chamber and close the gate valve to isolate the growth chamber and the sample transfer chamber.

[0060] S3: adjusting the position of the substrate stage and turning on the hollow magnetic coupling device to make the substrate stage start to rotate;

[0061] S4: heating the evaporation source 12 and the electron gun 13 so that the internal temperature reaches the melting temperature of the evaporation material and remains stable, and then, according to the actual situation, the evaporation source 12 and the electron gun 13 are used in a superimposed or alternating manner to perform evaporation treatment on the wafer;

[0062] S5: After the wafer evaporation is completed, the hollow magnetic coupler 142, the evaporation source 12 and the electron gun 13 are closed in sequence, and the cold trap 15 is kept working to allow the equipment to naturally cool down to room temperature. After the temperature stabilizes, the wafer sample is taken out.

[0063] The working principle and use process of the present invention are as follows: first, ensure that the internal environment of each chamber is in an atmospheric state to avoid accidents when opening the chamber, open the quick-opening door of the sample transfer chamber 2, place the wafer on the sample rack 21, close the quick-opening door, close the gate valve 3, and respectively start the mechanical pumps of the growth chamber 1 and the sample transfer chamber 2. When the vacuum degree reaches below 50Pa, both the growth chamber 1 and the sample transfer chamber 2 start the molecular pump 201 (when the vacuum is evacuated from the atmosphere for the first time, there is a large amount of water vapor and other gases in the chamber that are difficult to extract in ultra-high vacuum. Therefore, it is necessary to bake and degas the growth chamber 1 and the sample transfer chamber 2 after the vacuum degree in the chamber is relatively stable. The baking time is about two to three days. After the baking is completed, the temperature of the growth chamber 1 drops below 100°C), then start the ion pump of the compound pump, and set the ignition cycle of the titanium sublimation pump in the compound pump. When the vacuum degree of the growth chamber 1 and the sample transfer chamber 2 meets the requirements, the gate valve 3 can be opened at this time, and the lifting component can be rotated to remove the gas. 22 controls the height and angle of the sample holder 21 and cooperates with the sample transfer rod 23 to transfer the wafer to the manipulator on the sample transfer rod 203, drives the magnetic coupling linear drive of the sample transfer rod 203, moves the manipulator to the growth chamber 1, adjusts the sample stage 14 to an appropriate height and angle, places the wafer on the substrate stage 141, moves the manipulator to the sample transfer chamber 2, closes the gate valve 3 and waits for the vacuum degree of the growth chamber 1 to stabilize, moves the substrate stage 141 to a certain angle position determined by the evaporation source 12, starts the continuous rotation of the hollow magnetic coupling 142, and before the evaporation source 12 is installed in the growth chamber 1, adds 1 / 3 of the volume of evaporation material to the PBN crucible inside the evaporation source 12, connects the thermocouple 148 to the power supply temperature control meter, and activates the controller to heat the material to the melting temperature. At the same time, ensure that there is uninterrupted circulating water in the integrated water cooling, rotate the magnetic coupling to keep the baffle in a shielded state, open the baffle when the melting temperature is stable, and start evaporation. The electron gun 13 is the same as the evaporation source 12. When the evaporation source 12 or the electron gun 13 is heated, the cold trap 15 is filled with liquid nitrogen, and the heater 145 of the sample stage 14 is controlled to heat up to the required temperature. When both are heated to the required temperature, the baffle is opened to evaporate and deposit the film. When the electron gun 13 and the evaporation source 12 are used for co-evaporation and deposition of the film, it is necessary to ensure that the cold trap 15 circulates liquid nitrogen normally to prevent the cavity from being subjected to thermal radiation and causing the temperature to be too high. At the same time, the temperature control power supply of the electron gun 13 and the evaporation source 12 is controlled to heat up, and gradually heat up to the required melting temperature of the evaporation material. Observe whether there is obvious light in the crucible of the cavity. After the light appears and the temperature is stable, open the baffle for evaporation. When the electron gun 13 and the evaporation source 12 are used alternately for evaporation, it is recommended to use the evaporation source 12 first. This is because the electron gun 13 is placed vertically below the sample stage 14. Using the electron gun 13 later can improve the uniformity of the film. The heating operation of the electron gun 105 and the evaporation source 106 used alternately is consistent with the superposition use.After the film deposition is completed, first turn off the rotation of all baffles and the hollow magnetic coupler 142, and perform step-by-step cooling on the heater 145, the evaporation source 12 and the electron gun 13. The power supply cannot be turned off directly to avoid large thermal strain on the material. After the thermocouple 148 detects that the temperature has dropped to room temperature, stop filling with liquid nitrogen.

[0064] Although this specification is described according to implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0065] Therefore, the above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application; that is, all equivalent changes made according to the scope of the claims of the present application are within the protection scope of the claims of the present application.

Claims

1. An integrated molecular beam epitaxy device, comprising a growth chamber and a sample transfer chamber, wherein a gate valve for controlling the connection and isolation between the growth chamber and the sample transfer chamber is installed between the growth chamber and the sample transfer chamber, wherein the growth chamber and the sample transfer chamber are both arranged on a support frame, and a vacuum pumping system is installed on the growth chamber and the sample transfer chamber, wherein: The growth chamber includes a deposition chamber, on which an evaporation source and an electron gun are respectively installed, and are configured to be superimposed and / or alternately used to evaporate and coat a substrate located in the deposition chamber. A sample stage is installed on the deposition chamber for providing support and heating for the substrate located in the deposition chamber.

2. The integrated molecular beam epitaxy device according to claim 1, characterized in that: A cold trap is provided on the sample stage and is located in the deposition chamber. The cold trap includes an upper cold trap chamber and a lower cold trap chamber that are independent of each other. Both the upper cold trap chamber and the lower cold trap chamber adopt a hollow-out design in the middle. The upper cold trap chamber and the lower cold trap chamber are connected by a plurality of support rods for balancing the support force. A liquid nitrogen inlet and a liquid nitrogen outlet are installed in the upper cold trap chamber. Two fluid pipes that connect the upper cold trap chamber and the lower cold trap chamber are also provided between the upper cold trap chamber and the lower cold trap chamber for realizing the circulation of liquid nitrogen in the upper cold trap chamber and the lower cold trap chamber.

3. The integrated molecular beam epitaxy device according to claim 1, characterized in that: A chamber cover is provided above the deposition chamber, and a baffle assembly and a hydraulic feedthrough are respectively installed on the chamber cover. There are two hydraulic feedthroughs, and the two hydraulic feedthroughs are respectively connected to the liquid nitrogen inlet and the liquid nitrogen outlet.

4. The integrated molecular beam epitaxy device according to claim 1, characterized in that: The deposition chamber is equipped with a film thickness meter, a RHEED high energy reflection electron diffractometer, a fluorescent screen, a vacuum gauge, an observation window and an ion gauge.

5. The integrated molecular beam epitaxy device according to claim 1, characterized in that: The vacuum pumping system comprises two molecular pumps, and the two molecular pumps are respectively connected with the inside of the growth chamber and the sample transfer chamber, wherein a compound pump is also installed on the growth chamber.

6. The integrated molecular beam epitaxy device according to claim 1, characterized in that: The sample stage comprises: A substrate stage, used for carrying a substrate to be processed; A hollow magnetic coupling is arranged above the substrate stage to drive the substrate stage to rotate; A linear drive assembly is used to control the lifting movement of the substrate stage; the linear drive is connected to a flange, and a connecting pipe connected to a heater is installed on the flange. The heater is powered by a heating power feedthrough and is connected to a thermocouple to achieve temperature monitoring and control.

7. The integrated molecular beam epitaxy device according to claim 1, characterized in that: A sample rack is provided inside the cavity of the sample transfer chamber for placing wafers to be tested. The sample rack is equipped with a rotating lifting assembly that can accurately adjust and position the wafers. A sample transfer rod is also installed on the sample transfer chamber for performing automated conveying and retrieval tasks of wafers.

8. A method for using the integrated molecular beam epitaxy device according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: Place the wafer to be prepared on the sample holder, and add corresponding evaporation materials to the evaporation source and electron gun respectively according to the characteristics of the film to be prepared. Then start the vacuum system to make the vacuum degree in the growth chamber and the sample transfer chamber reach the preset requirements, and open the gate valve to prepare for sample transfer; S2: Start the sample transfer rod, extend it and send the wafer on the sample holder to the substrate table in the growth chamber. After the wafer is stable, retract the sample transfer rod into the sample transfer chamber and close the gate valve to isolate the growth chamber and the sample transfer chamber. S3: adjusting the position of the substrate stage and turning on the hollow magnetic coupling device to make the substrate stage start to rotate; S4: heating the evaporation source and the electron gun so that the internal temperature reaches the melting temperature of the evaporation material and remains stable, and then, according to the actual situation, the evaporation source and the electron gun are used alternately to perform evaporation treatment on the wafer; S5: After the wafer evaporation is completed, the hollow magnetic coupling, evaporation source and electron gun are turned off in sequence, and the cold trap is kept working to allow the equipment to cool down naturally to room temperature. After the temperature stabilizes, the wafer sample is taken out.

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