A molecular beam epitaxy apparatus contamination in-situ cleaning system and method

Abstract

The application relates to the technical field of semiconductor manufacturing equipment, and particularly provides a molecular beam epitaxy equipment pollutant in-situ cleaning system and method. The system comprises a radiation heating unit, a condensation capturing unit, a temperature acquisition assembly and a controller. The controller is used for acquiring metal type information of a metal to be cleaned and current vacuum degree of the molecular beam epitaxy equipment when the molecular beam epitaxy equipment does not perform a process, then determining a target temperature interval according to the metal type information and the current vacuum degree, and further used for controlling the condensation capturing unit to switch to a low-position working state, and controlling the radiation heating unit to perform radiation heating on a substrate heater, so that side wall temperature information is located in the target temperature interval, until a time length during which the side wall temperature information is maintained in the target temperature interval reaches a preset time length, and then controlling the condensation capturing unit to switch to a high-position retracted state. The system can effectively reduce the pollutant deposition amount of the substrate heater side wall.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing equipment technology, and more specifically, to an in-situ cleaning system and method for contaminants in molecular beam epitaxy equipment. Background Technology

[0002] Molecular beam epitaxy (MBE), a core process in the modern semiconductor industry, enables the growth of high-quality crystalline thin films with atomic-level flatness and precise composition on substrates under ultra-high vacuum conditions by controlling atomic or molecular beams. This technology is a crucial foundation for fabricating high-performance microwave devices, optoelectronic devices, and cutting-edge quantum computing structures. In the growth chamber of an MBE facility, the substrate heater is a centrally located core component. Its sidewalls, due to their large surface area and proximity to the molecular beam, become the primary deposition area for metal materials outside the substrate. Over long-term operation, metals such as aluminum, gallium, and indium form thick, irregular films on the sidewalls of the substrate heater. Due to the mismatch in thermal expansion coefficients with the substrate, these films generate stress during repeated thermal cycling, eventually leading to cracking and warping, forming unstable metal fragments or flakes suspended on the sidewalls of the substrate heater. These metal fragments or flakes are susceptible to detachment due to mechanical vibration, thermal shock, or gravity, causing serious contamination problems.

[0003] Currently, the only viable solution is complete shutdown and manual cleaning of the cavity. This method has several inherent drawbacks: First, opening the cavity completely destroys the ultra-high vacuum and ultra-clean cavity environment upon which MBE technology relies; second, the manual cleaning process inevitably introduces particulate contaminants such as human skin flakes and dust; and finally, the entire cleaning-restoration cycle is extremely long, severely impacting equipment utilization. These drawbacks severely restrict the production efficiency and cost control of MBE equipment.

[0004] There is currently no effective technical solution to the above problems. Summary of the Invention

[0005] The purpose of this application is to provide an in-situ cleaning system and method for contaminants in a molecular beam epitaxy (MBE) device. This system can effectively reduce the amount of contaminant deposits on the sidewalls of the substrate heater by in-situ heating the substrate heater when the device is not in operation, causing the metal contaminants to sublimate, and then using a condensation capture unit to capture the sublimated metal contaminants.

[0006] In a first aspect, this application provides an in-situ contaminant cleaning system for molecular beam epitaxy equipment, used to clean metallic contaminants deposited on the sidewalls of a substrate heater in a molecular beam epitaxy equipment, comprising: The radiation heating unit is installed on the molecular beam epitaxy equipment; The condensation trapping unit is located inside the molecular beam epitaxy equipment and can switch between two states: high-position retraction and low-position operation. When the condensation trapping unit is in the high-position retraction state, the distance between it and the substrate heater is greater than when it is in the low-position operation state. A temperature acquisition component, installed on a molecular beam epitaxy device, is used to acquire sidewall temperature information of the substrate heater. The controller is used to acquire the metal type information of the metal to be cleaned and the current vacuum level of the molecular beam epitaxy equipment when no process is being performed. Then, it determines the target temperature range based on the metal type information and the current vacuum level. The lower limit of the target temperature range is greater than the sublimation temperature of the metal to be cleaned at the current vacuum level, and the upper limit of the target temperature range is less than the preset recrystallization temperature corresponding to the substrate heater and the first preset safety temperature corresponding to the cold screen of the molecular beam epitaxy equipment. It is also used to control the condensation capture unit to switch to a low-level working state and control the radiation heating unit to radiate heat the substrate heater so that the sidewall temperature information is within the target temperature range until the sidewall temperature information is maintained within the target temperature range for a preset duration. Then, it controls the condensation capture unit to switch to a high-level retracted state.

[0007] Optionally, when there are multiple metals to be cleaned, there are multiple metal type information and multiple target temperature ranges. Each metal to be cleaned corresponds to one metal type information and one target temperature range. The process of controlling the condensation capture unit to switch to a low-level working state and controlling the radiation heating unit to radiate heat the substrate heater so that the sidewall temperature information is within the target temperature range, until the sidewall temperature information is maintained within the target temperature range for a preset duration, and then controlling the condensation capture unit to switch to a high-level retracted state includes: A1. Control the condensation capture unit to switch to low-level working state; A2. Select the target temperature range with the smallest upper limit value; A3. Control the radiation heating unit to radiate heat the sidewall of the substrate heater so that the sidewall temperature information is within the currently selected target temperature range; A4. Use the radiant heating unit to maintain the side wall temperature information within the currently selected target temperature range until the side wall temperature information is maintained within the target temperature range for a preset duration. A5. Delete the currently selected target temperature range, and then analyze whether a target temperature range still exists. If yes, return to step A2; otherwise, proceed to step A6. A6. Control the radiant heating unit to stop radiant heating and control the condensation capture unit to stop cooling. Then, when the temperature of the condensation capture unit rises to the second preset safe temperature, control the condensation capture unit to switch to the high-level retracted state.

[0008] Optionally, the in-situ contaminant cleaning system of the molecular beam epitaxy equipment also includes a gaseous metal atom concentration acquisition component. This component is used to acquire the concentration information of gaseous atoms formed by the sublimation of the metal to be cleaned in the region between the substrate heater and the condensation trapping unit. Step A4 includes: A41. Obtain the corresponding preset concentration threshold based on the metal to be cleaned corresponding to the currently selected target temperature range. A42. Use the radiant heating unit to maintain the sidewall temperature within the currently selected target temperature range; A43. Analyze whether the sidewall temperature information is maintained within the target temperature range for a preset duration and the concentration of gaseous atoms formed by the sublimation of the metal to be cleaned corresponding to the currently selected target temperature range is less than the preset concentration threshold. If yes, proceed to step A5; otherwise, return to step A42.

[0009] Optionally, the gaseous metal atom concentration acquisition component includes a quadrupole mass spectrometer. The metal to be cleaned is indium, gallium, or aluminum. The quadrupole mass spectrometer acquires the concentration information of indium in the region between the substrate heater and the condensation trapping unit by acquiring the ion current intensity of mass numbers 113 and 115. The quadrupole mass spectrometer acquires the concentration information of gallium in the region between the substrate heater and the condensation trapping unit by acquiring the ion current intensity of mass number 69. The quadrupole mass spectrometer acquires the concentration information of aluminum in the region between the substrate heater and the condensation trapping unit by acquiring the ion current intensity of mass number 27.

[0010] Optionally, step A4 includes: A41. Use the median value of the currently selected target temperature range as the preset reference temperature; A42. The PID controller adjusts the heating power of the radiant heating unit according to the side wall temperature information and the preset reference temperature to maintain the side wall temperature information within the currently selected target temperature range until the side wall temperature information is maintained within the target temperature range for a preset duration.

[0011] Optionally, the condensation capture unit includes a capture hood, a cooling medium supply component, and a lifting component. The lifting component is disposed within the molecular beam epitaxy equipment and above the substrate heater. The capture hood retracts upward and has an opening at its lower end. The capture hood is connected to the lifting component. The lifting component is used to drive the capture hood to rise or fall, thereby switching the condensation capture unit between two states: a high-position retracted state and a low-position working state. A cooling medium flow channel is provided inside the capture hood. The cooling medium supply component is connected to the cooling medium flow channel and is used to supply cooling medium to the cooling medium flow channel.

[0012] Optionally, the ratio of the diameter of the lower opening of the trap to the diameter of the substrate heater is 2-2.5, and the angle between the sidewall of the trap and the vertical line is 45-50°.

[0013] Optionally, the radiation heating unit includes an infrared radiation heating gun. The installation height of the infrared radiation heating gun is less than the height of the top surface of the substrate heater. The irradiation point of the infrared radiation heating gun on the substrate heater is located on the side wall of the substrate heater. When the condensation capture unit switches to the low-level working state, the height of the lower opening of the capture cover is less than the height of the top surface of the substrate heater and greater than the height of the irradiation point of the infrared radiation heating gun.

[0014] Optionally, there are multiple radiation heating units, which are arranged in a circular array on the molecular beam epitaxy device.

[0015] Secondly, this application also provides an in-situ cleaning method for contaminants in a molecular beam epitaxy (MBE) apparatus, used to clean metallic contaminants deposited on the sidewalls of a substrate heater in an MBE apparatus, applied in the in-situ cleaning system for contaminants in an MBE apparatus provided in the first aspect. The in-situ cleaning method for contaminants in an MBE apparatus includes the following steps: S1. When the molecular beam epitaxy (MBE) equipment is not performing any processes, obtain the metal type information of the metal to be cleaned and the current vacuum level of the MBE equipment. Then, determine the target temperature range based on the metal type information and the current vacuum level. The lower limit of the target temperature range is greater than the sublimation temperature of the metal to be cleaned under the current vacuum level, and the upper limit of the target temperature range is less than the preset recrystallization temperature corresponding to the substrate heater and the first preset safety temperature corresponding to the cold screen of the MBE equipment. S2. Control the condensation capture unit to switch to low-level working state and control the radiation heating unit to radiate heat the substrate heater so that the sidewall temperature information is within the target temperature range until the sidewall temperature information is maintained within the target temperature range for a preset duration.

[0016] As can be seen from the above, the in-situ contaminant cleaning system and method for molecular beam epitaxy equipment provided in this application effectively reduces the amount of contaminant deposited on the sidewall of the substrate heater by heating the substrate heater in situ when the equipment is not performing the process, causing the metal contaminants to sublimate, and then using a condensation capture unit to capture the sublimated metal contaminants. This minimizes the number of times the cavity is opened for cleaning, thereby minimizing the damage to the vacuum environment and the introduction of additional contaminants caused by the cavity opening cleaning, and effectively improving the utilization rate of the molecular beam epitaxy equipment. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an in-situ contaminant cleaning system for a molecular beam epitaxy device, provided in an embodiment of this application.

[0018] Figure 2 This is a cross-sectional structural schematic diagram of an in-situ contaminant cleaning system for a molecular beam epitaxy device provided in an embodiment of this application.

[0019] Figure 3 This is a schematic diagram of the connection relationship of an in-situ contaminant cleaning system for a molecular beam epitaxy device provided in an embodiment of this application.

[0020] Figure 4 This is a flowchart illustrating an in-situ cleaning method for contaminants in a molecular beam epitaxy device, provided as an embodiment of this application.

[0021] Reference numerals: 1. Molecular beam epitaxy equipment; 2. Substrate heater; 3. Radiation heating unit; 4. Condensation and capture unit; 41. Capture hood; 42. Lifting assembly; 5. Temperature acquisition assembly; 6. Controller; 7. Gaseous metal atom concentration acquisition assembly. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0023] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] Firstly, such as Figures 1-3 As shown, this application provides an in-situ contaminant cleaning system for a molecular beam epitaxy (MBE) apparatus, used to clean metallic contaminants deposited on the sidewall of the substrate heater 2 in a MBE apparatus 1, comprising: Radiation heating unit 3 is installed on molecular beam epitaxy equipment 1; The condensation capture unit 4 is installed inside the molecular beam epitaxy device 1 and can switch between two states: high-position retraction and low-position operation. When the condensation capture unit 4 is in the high-position retraction state, the distance between it and the substrate heater 2 is greater than the distance between it and the substrate heater 2 when it is in the low-position operation state. Temperature acquisition component 5 is installed on molecular beam epitaxy equipment 1 and is used to acquire sidewall temperature information of substrate heater 2; The controller 6 is used to acquire the metal type information of the metal to be cleaned and the current vacuum level of the molecular beam epitaxy equipment 1 when no process is being performed in the molecular beam epitaxy equipment 1. Then, it determines the target temperature range based on the metal type information and the current vacuum level. The lower limit of the target temperature range is greater than the sublimation temperature of the metal to be cleaned under the current vacuum level, and the upper limit of the target temperature range is less than the preset recrystallization temperature corresponding to the substrate heater 2 and the first preset safety temperature corresponding to the cold screen of the molecular beam epitaxy equipment 1. It is also used to control the condensation capture unit 4 to switch to the low-level working state and control the radiation heating unit 3 to radiate heat the substrate heater 2 so that the sidewall temperature information is within the target temperature range until the sidewall temperature information is maintained within the target temperature range for a preset duration. Then, it controls the condensation capture unit 4 to switch to the high-level retracted state.

[0025] For ease of understanding, some key terms in this embodiment are explained below. The in-situ contaminant cleaning system for molecular beam epitaxy equipment in this embodiment aims to remove metal contaminants deposited on the sidewall of substrate heater 2 without opening the chamber of molecular beam epitaxy equipment 1. This system integrates functions such as radiation heating, condensation capture, temperature monitoring, and intelligent control to remove as much metal contaminant as possible from the sidewall of substrate heater 2, thereby reducing the need for traditional open-chamber cleaning and improving equipment utilization. It should be understood that if too much metal contaminant is observed deposited on the sidewall of substrate heater 2 through the viewing window of molecular beam epitaxy equipment 1 and cannot be effectively removed, then traditional open-chamber cleaning methods are required to clean substrate heater 2. That is, this application may not be able to achieve 100% removal of metal contaminants deposited on the sidewall of substrate heater 2. This application aims to minimize the number of open-chamber cleaning operations by minimizing the amount of metal contaminant deposited on the sidewall of substrate heater 2. The radiation heating unit 3 in this embodiment is the core heating component of the cleaning system. Its function is to radiate heat the substrate heater 2 to heat the metal contaminants deposited on the sidewall of the substrate heater 2 to above its sublimation temperature, thereby causing the metal contaminants deposited on the sidewall of the substrate heater 2 to change from solid to gaseous. The gaseous metal contaminants will separate from the sidewall of the substrate heater 2. The separated gaseous metal contaminants will be captured by the condensation and capture unit 4 by condensation, thereby removing the metal contaminants from the sidewall of the substrate heater 2. It should be understood that the in-situ cleaning system for contaminants in molecular beam epitaxy equipment provided in this application is equivalent to transferring the metal contaminants from the sidewall of the substrate heater 2 to the condensation and capture unit 4. The condensation trapping unit 4 in this embodiment is used to trap gaseous metal atoms formed by sublimation from the sidewall of the substrate heater 2. This unit can switch between two states: high-level retraction and low-level operation. In the low-level operation state, the condensation trapping unit 4 is close to the substrate heater 2 to efficiently trap the sublimated gaseous metal atoms. In the high-level retraction state, the condensation trapping unit 4 is far away from the epitaxial growth region. Therefore, during the epitaxial growth process, the temperature of the condensation trapping unit 4 will not fluctuate significantly, thereby effectively avoiding the situation where stress is generated between the condensation trapping unit 4 and the trapped metal contaminants due to the mismatch of the thermal expansion coefficients of the condensation trapping unit 4 and the trapped metal contaminants caused by significant temperature fluctuations in the condensation trapping unit 4. This prevents the metal contaminants trapped by the condensation trapping unit 4 from falling off during the epitaxial growth process by keeping the condensation trapping unit 4 in a high-level retraction state.In this embodiment, the temperature acquisition component 5 is used to monitor the temperature information of the sidewall of the substrate heater 2 in real time. The accurate temperature information is the basis for the controller 6 to perform heating control, ensuring that the sidewall temperature is maintained within the target temperature range. Since the lower limit of the target temperature range is greater than the sublimation temperature of the metal to be cleaned under the current vacuum, and the upper limit of the target temperature range is less than the preset recrystallization temperature corresponding to the substrate heater 2 and the first preset safety temperature corresponding to the cold screen of the molecular beam epitaxy equipment 1 (the safety temperature of the cold screen is the lowest among all components of the molecular beam epitaxy equipment 1, so making the upper limit of the target temperature range less than the first preset safety temperature corresponding to the cold screen of the molecular beam epitaxy equipment 1 can avoid damage to all components of the molecular beam epitaxy equipment 1), this embodiment achieves both effective sublimation of contaminants and avoidance of damage to the substrate heater 2 and other components of the molecular beam epitaxy equipment 1 by controlling the temperature of the sidewall of the substrate heater 2 within the target temperature range. The controller 6 in this embodiment is the intelligent core of the entire cleaning system. It is responsible for coordinating and managing the work of each component. Its functions include acquiring information about the type of metal to be cleaned and the current vacuum level of the molecular beam epitaxy device 1, determining a suitable target temperature range based on this information, and controlling the operating status of the radiation heating unit 3 and the condensation capture unit 4 to achieve effective in-situ cleaning of metal contaminants on the sidewall of the substrate heater 2.

[0026] This application proposes an in-situ contaminant cleaning system for a molecular beam epitaxy (MBE) apparatus, used to clean metallic contaminants deposited on the sidewall of a substrate heater 2 in an MBE apparatus 1. The system includes a radiation heating unit 3, a condensation capture unit 4, a temperature acquisition component 5, and a controller 6. In this embodiment, the radiation heating unit 3 is disposed on the MBE apparatus 1 and is used to radiate heat the substrate heater 2. This radiation heating unit 3 can be a halogen lamp heater, using infrared radiation emitted by a halogen bulb to heat the sidewall. In this embodiment, the condensation capture unit 4 is disposed within the molecular beam epitaxy apparatus 1 and can switch between two states: high-position retracted and low-position operation. In the high-position retracted state, the distance between the condensation capture unit 4 and the substrate heater 2 is greater than in the low-position operation state. The condensation capture unit 4 can consist of a capture shroud 41 and a robotic arm. The capture shroud 41 is used to condense gaseous atoms formed by the sublimation of metal contaminants to capture these gaseous atoms. In the low-position operation state, the condensation capture unit 4 is positioned close to the sidewall of the substrate heater 2 to efficiently capture sublimated metal atoms. In the high-position retracted state, the condensation capture unit 4 is raised to a position away from the epitaxial growth region to avoid affecting the process environment during epitaxial growth and to prevent the captured metal contaminants from falling off. In this embodiment, the temperature acquisition component 5 is disposed on the molecular beam epitaxy apparatus 1 and is used to acquire the sidewall temperature information of the substrate heater 2. The temperature acquisition component 5 can be implemented using an infrared thermometer, which calculates the temperature by receiving infrared radiation emitted from the sidewall. In this embodiment, the controller 6 is used to acquire the metal type information of the metal to be cleaned and the current vacuum level of the molecular beam epitaxy (MBE) equipment 1 when no process is being performed. Then, based on the metal type information and the current vacuum level, it determines the target temperature range. The controller 6 can also control the condensation capture unit 4 to switch to a low-level operating state and control the radiation heating unit 3 to radiate heat the substrate heater 2, ensuring that the sidewall temperature information is within the target temperature range. This continues until the sidewall temperature information remains within the target temperature range for a preset duration, at which point the condensation capture unit 4 switches to a high-level retracted state. The controller 6 can be a programmable logic controller (PLC) or an embedded system, internally storing sublimation temperature data for different metals at different vacuum levels. Before cleaning, the operator can input the type of metal to be cleaned through a human-machine interface. The controller 6, based on the input metal type and the current vacuum level, obtains the target temperature range by querying a pre-built mapping table of metal type and vacuum level combinations and their corresponding sublimation temperature ranges. For example, if the metal to be cleaned is gallium and the current vacuum level is 10... -9 The controller 6 will query the sublimation temperature range of gallium under this vacuum level. This temperature range is the range that can effectively sublimate gallium without damaging the device.

[0027] The following is a more specific example to illustrate the above technical solution in greater detail: Suppose that a large amount of gallium metal contaminants are deposited on the sidewall of the substrate heater 2 in the molecular beam epitaxy (MBE) equipment 1. Traditional cleaning methods require shutdown and manual cleaning by opening the cavity, which is not only time-consuming and labor-intensive but also disrupts the ultra-high vacuum environment and introduces new contamination risks. To solve this problem, the in-situ contaminant cleaning system for MBE equipment proposed in this application is implemented. First, when MBE equipment 1 is not performing any processing, the controller 6 obtains the type information of the metal to be cleaned as "gallium" and acquires the current vacuum level of MBE equipment 1 as 10. -9 Based on this information, controller 6 determines a target temperature range using its internally stored database and algorithms. The lower limit of this target temperature range is set to be higher than gallium by 10°C. -9The target temperature range is set to the sublimation temperature under vacuum to ensure effective gallium sublimation. Simultaneously, the upper limit of this target temperature range is set below the preset recrystallization temperature of the substrate heater 2 and the first preset safety temperature of the cold shield of the molecular beam epitaxy equipment 1 to avoid damage to the equipment. For example, the target temperature range is determined to be 600°C to 650°C. Subsequently, the controller 6 issues a command to switch the condensation capture unit 4 to a low-position operating state. At this time, the condensation capture unit 4 descends from its high-position retracted state, approaching the sidewall of the substrate heater 2, reducing its distance from the substrate heater 2, preparing for the capture of sublimated metal atoms. Simultaneously, the controller 6 activates the radiation heating unit 3 to radiate heat the sidewall of the substrate heater 2. The temperature acquisition component 5 collects the temperature information of the sidewall of the substrate heater 2 in real time and feeds this information back to the controller 6. Based on the feedback temperature information, the controller 6 precisely adjusts the heating power of the radiation heating unit 3 to maintain the sidewall temperature within the target temperature range of 600°C to 650°C. While the sidewall temperature remains within the target temperature range, gallium metal contaminants deposited on the sidewall of substrate heater 2 begin to sublimate, forming gaseous gallium atoms. These gaseous gallium atoms move upward within the molecular beam epitaxy apparatus 1 and are captured and condensed on its surface by the condensation trapping unit 4, which is in a low-position operating state. This process continues until the sidewall temperature remains within the target temperature range for a preset duration (e.g., 2 hours) to ensure that most or all of the gallium deposited on the sidewall of substrate heater 2 is effectively removed. After cleaning, controller 6 first controls the radiation heating unit 3 to stop heating and then controls the condensation trapping unit 4 to stop cooling. When the temperature of the condensation trapping unit 4 rises to a second preset safe temperature, controller 6 controls the condensation trapping unit 4 to switch to a high-position retracted state. At this time, the condensation trapping unit 4 rises, moving away from substrate heater 2 and the epitaxial growth area. Because the condensation trapping unit 4 remains in a high-position retracted state during epitaxial growth, its temperature does not fluctuate significantly, effectively avoiding stress caused by the mismatch in thermal expansion coefficients between the condensation trapping unit 4 and the captured metal contaminants, which could lead to the fall of the captured metal contaminants.

[0028] As can be seen from the above examples, the in-situ contaminant cleaning system for molecular beam epitaxy (MBE) equipment of this application precisely heats the sidewall of the substrate heater 2 through the radiation heating unit 3, causing the metal contaminants to sublimate, and then efficiently captures the sublimated metal atoms using the condensation trapping unit 4. The controller 6 intelligently determines the target temperature range based on the metal type and the current vacuum level of the MBE equipment 1, ensuring the effectiveness and safety of the cleaning process. Compared with traditional open-cavity cleaning methods, the system of this application achieves in-situ cleaning, avoiding damage to the ultra-high vacuum environment and the introduction of new contamination risks, significantly reducing downtime and recovery cycles, and improving equipment utilization. In addition, the design of the condensation trapping unit 4 in a high-position retracted state effectively solves the risk of metal contaminants captured by the condensation trapping unit 4 falling off after cleaning, ensuring the purity of subsequent epitaxial growth processes. This integrated in-situ cleaning scheme provides an efficient, reliable, and non-destructive solution for the maintenance of MBE equipment 1, with significant technological advancements and industrial application value.

[0029] In some preferred embodiments, when multiple metals to be cleaned exist, there are multiple metal type information and multiple target temperature ranges. Each metal to be cleaned corresponds to one metal type information and one target temperature range. The process of controlling the condensation capture unit 4 to switch to a low-level working state and controlling the radiation heating unit 3 to radiate heat the substrate heater 2 so that the sidewall temperature information is within the target temperature range, until the sidewall temperature information is maintained within the target temperature range for a preset duration, and then controlling the condensation capture unit 4 to switch to a high-level retracted state includes: A1. Control the condensation capture unit 4 to switch to low-level working state; A2. Select the target temperature range with the smallest upper limit value; A3. Control the radiation heating unit 3 to radiate heat the sidewall of the substrate heater 2 so that the sidewall temperature information is within the currently selected target temperature range; A4. Use the radiant heating unit 3 to maintain the side wall temperature information within the currently selected target temperature range until the side wall temperature information is maintained within the target temperature range for a preset duration. A5. Delete the currently selected target temperature range, and then analyze whether a target temperature range still exists. If yes, return to step A2; otherwise, proceed to step A6. A6. Control the radiant heating unit 3 to stop radiant heating and control the condensation capture unit 4 to stop cooling. Then, when the temperature of the condensation capture unit 4 rises to the second preset safe temperature, control the condensation capture unit 4 to switch to the high-level retracted state.

[0030] When the system detects the presence of multiple metals to be cleaned (since each metal source furnace in the molecular beam epitaxy device 1 is used to store and heat one type of metal, this embodiment can analyze the presence of multiple metals to be cleaned by analyzing whether the molecular beam epitaxy device 1 includes multiple metal source furnaces), it establishes corresponding metal type information and target temperature range for each metal. The metal type information can be an identifier of the metal element name, such as "aluminum," "gallium," or "indium," or its chemical symbol. The target temperature range is a temperature range whose lower limit must be greater than the sublimation temperature of the metal under the current vacuum level to ensure effective sublimation; its upper limit must be less than the preset recrystallization temperature corresponding to the substrate heater 2 and the first preset safety temperature corresponding to the cold screen of the molecular beam epitaxy device 1 to avoid damage to the equipment. Switching the condensation capture unit 4 to a low-position working state means that the condensation capture unit 4 is moved from its high-position retracted position to a low-position working position close to the substrate heater 2 by a drive mechanism (e.g., a linear motor or pneumatic actuator) to effectively capture sublimated metal atoms. The radiant heating unit 3 radiates heat to the substrate heater 2 by applying power to the radiant heating unit 3 (e.g., an infrared heating lamp or a resistance heater), causing it to emit radiant energy, thereby increasing the temperature of the sidewall of the substrate heater 2. The sidewall temperature information is within the target temperature range. This is monitored in real time by the temperature acquisition component 5 (e.g., an infrared thermometer or thermocouple), and this temperature information is fed back to the controller 6. The controller 6 adjusts the heating power of the radiant heating unit 3 according to a preset control algorithm (e.g., PID control) to stabilize the sidewall temperature within the target temperature range. The duration for which the sidewall temperature information is maintained within the target temperature range reaches a preset duration refers to the timer inside the controller 6 recording the duration for which the sidewall temperature remains within the target temperature range. When this time reaches the preset value, it indicates that the current metal cleaning process has been fully completed. Deleting the currently selected target temperature range means that the controller 6 removes the target temperature range corresponding to the cleaned metal from the pending processing list. Analyzing whether a target temperature range still exists means that the controller 6 checks whether there are still uncleaned metals corresponding to their target temperature ranges in the pending processing list. Controlling the radiant heating unit 3 to stop radiant heating and controlling the condensation capture unit 4 to stop cooling means that the controller 6 sends a stop heating command to the radiant heating unit 3 and a stop cooling medium supply command to the cooling medium supply component, so that the condensation capture unit 4 can naturally heat up.

[0031] This embodiment solves the problem of improper temperature control when multiple metals coexist by serializing the cleaning process of multiple metal contaminants. At the start of cleaning, the controller 6 first moves the condensation capture unit 4 to a low-level operating state to prepare for capturing sublimated metal atoms. Subsequently, the controller 6 selects the range with the smallest upper limit from all the target temperature ranges corresponding to the metals to be cleaned as the current cleaning target. This selection strategy ensures that metals with lower sublimation temperatures are processed first, avoiding a situation where there are too many gaseous metal atoms due to the simultaneous sublimation of multiple metal contaminants, making it impossible for the condensation capture unit 4 to effectively capture the gaseous metal atoms. Once the current target temperature range is determined, the controller 6 precisely controls the radiation heating unit 3 to radiate heat the sidewall of the substrate heater 2 to raise the sidewall temperature to within the target temperature range. Subsequently, the controller 6 dynamically adjusts the heating power of the radiation heating unit 3 according to the sidewall temperature information monitored by the temperature acquisition component 5 to maintain the sidewall temperature within the target temperature range. When the sidewall temperature is maintained within the target temperature range for a preset duration, it indicates that the metal contaminants deposited on the sidewall of the substrate heater 2 have been fully sublimated and captured by the condensation capture unit 4. At this point, controller 6 removes the processed target temperature range from the cleaning list and checks if there are any other metals to be cleaned (analyzing whether a target temperature space exists). If so, the system returns to the previous step, repeating the selection, heating, and maintenance process until all metal contaminants have been processed sequentially. This iterative cleaning method ensures that each metal can be effectively removed within its corresponding sublimation temperature range, avoiding the problem of incomplete gaseous atom capture and partial gaseous atom deposition on other components of the molecular beam epitaxy device 1 that may occur with single-temperature cleaning. Once all metal contaminants have been cleaned, controller 6 stops the radiation heating and cooling of the condensation capture unit 4. To ensure safety, the condensation capture unit 4 is not immediately retracted but waits for its temperature to rise naturally to the second preset safety temperature to prevent the captured metal contaminants from falling off due to thermal stress caused by drastic temperature fluctuations, thus avoiding the risk of secondary contamination. Only after the temperature reaches the safety threshold (the second preset safety temperature) will the condensation capture unit 4 be controlled to switch to the high-level retracted state, completing the entire cleaning cycle. Through this cleaning strategy of a low-to-high temperature sequence, the solution of this application significantly improves the safety of equipment operation while ensuring cleaning efficiency.

[0032] In some preferred embodiments, the in-situ contaminant cleaning system of the molecular beam epitaxy equipment further includes a gaseous metal atom concentration acquisition component 7, which is used to acquire the concentration information of gaseous atoms formed by the sublimation of the metal to be cleaned in the region between the substrate heater 2 and the condensation and capture unit 4. Step A4 includes: A41. Obtain the corresponding preset concentration threshold based on the metal to be cleaned corresponding to the currently selected target temperature range. A42. Use the radiant heating unit 3 to maintain the sidewall temperature information within the currently selected target temperature range; A43. Analyze whether the sidewall temperature information is maintained within the target temperature range for a preset duration and the concentration of gaseous atoms formed by the sublimation of the metal to be cleaned corresponding to the currently selected target temperature range is less than the preset concentration threshold. If yes, proceed to step A5; otherwise, return to step A42.

[0033] The gaseous metal atom concentration acquisition component 7 in this embodiment is used to monitor in real time the quantity or density of specific other metal atoms (gaseous atoms formed by the sublimation of the metal to be cleaned corresponding to the currently selected target temperature range) in a specific spatial region (the region between the substrate heater 2 and the condensation capture unit 4). As one implementation, this component can be a device based on the principle of mass spectrometry analysis, such as a quadrupole mass spectrometer, which infers the atomic concentration by detecting the current intensity of ions with a specific mass number. Alternatively, the component can be a sensor based on the principles of atomic absorption spectroscopy or atomic fluorescence spectroscopy, which determines the atomic concentration by detecting the absorption or emission of light at a specific wavelength. This embodiment aims to acquire the dynamic changes of metal atoms within the cleaning region in real time, serving as a key basis for judging the cleaning progress. In step A41, a corresponding preset concentration threshold is obtained based on the metal to be cleaned corresponding to the currently selected target temperature range. The purpose of this step is to set personalized cleaning completion standards for different types of metal contaminants to improve the accuracy of cleaning. One implementation is that the preset concentration threshold can be stored in a database inside the controller 6. This database sets an empirical concentration threshold for each metal to be cleaned under a specific vacuum degree based on experimental data or theoretical calculations. In step A42, the sidewall temperature is maintained within the currently selected target temperature range using the radiant heating unit 3. This step aims to ensure that the metal contaminants are continuously cleaned in a stable temperature environment conducive to sublimation. In step A43, it is analyzed whether the conditions are met simultaneously: the sidewall temperature is maintained within the target temperature range for a preset duration, and the concentration of gaseous atoms formed by the sublimation of the metal to be cleaned corresponding to the currently selected target temperature range is less than a preset concentration threshold. If yes, step A5 is executed; otherwise, step A42 is returned. This step introduces a dual judgment mechanism to ensure thorough cleaning.

[0034] This embodiment overcomes the limitations of traditional solutions that rely solely on time to determine the end of cleaning by introducing a gaseous metal atom concentration acquisition component 7 and optimizing the judgment logic during the cleaning process. Specifically, during the cleaning process, the controller 6 first obtains a preset concentration threshold based on the type of metal to be cleaned. This threshold is pre-set for the sublimation characteristics of different metals. Subsequently, the radiation heating unit 3 continuously radiates heat to the sidewall of the substrate heater 2 to maintain the sidewall temperature within the currently selected target temperature range, ensuring that metal contaminants can sublimate stably and continuously. During this process, the gaseous metal atom concentration acquisition component 7 monitors in real time the concentration of gaseous atoms formed by the sublimation of the metal to be cleaned in the area between the substrate heater 2 and the condensation capture unit 4. The controller 6 continuously analyzes the data, and only when the sidewall temperature remains within the target temperature range for a preset duration and the gaseous atom concentration is less than the preset concentration threshold is the cleaning task for the current metal determined to be complete. This dual judgment mechanism, combining cleaning time and actual contaminant concentration, makes the cleaning process no longer blindly time-driven, but rather a precise control based on the actual degree of contaminant removal. It should be understood that, as the sidewall temperature information is maintained within the currently selected target temperature range, the metal contaminants deposited on the sidewall of substrate heater 2 corresponding to the currently selected target temperature range will continue to sublimate and be continuously captured by the condensation and capture unit 4. As the amount of metal contaminants deposited on the sidewall of substrate heater 2 corresponding to the currently selected target temperature range gradually decreases, the concentration information of gaseous atoms gradually decreases. Therefore, when the concentration information drops below the preset threshold, it can be considered that most or all of the metal contaminants deposited on the sidewall of substrate heater 2 corresponding to the currently selected target temperature range have been removed. At this point, the process can be switched to cleaning the next metal contaminant or the cleaning process can be terminated. This mechanism, combined with the strategy of cleaning one by one by selecting the target temperature range with the smallest upper limit, ensures that each metal can be removed to the maximum extent in multi-metal contaminant scenarios. This effectively avoids the situation where the cleaning process is terminated even if there are still many metal contaminants left on the sidewall of substrate heater 2 due to using only the temperature maintenance time as the criterion for ending the cleaning process.

[0035] In some preferred embodiments, the gaseous metal atom concentration acquisition component 7 includes a quadrupole mass spectrometer. The metal to be cleaned is indium, gallium, or aluminum. The quadrupole mass spectrometer acquires the concentration information of indium in the region between the substrate heater 2 and the condensation trapping unit 4 by acquiring the ion current intensity with mass numbers of 113 and 115. The quadrupole mass spectrometer acquires the concentration information of gallium in the region between the substrate heater 2 and the condensation trapping unit 4 by acquiring the ion current intensity with mass number of 69. The quadrupole mass spectrometer acquires the concentration information of aluminum in the region between the substrate heater 2 and the condensation trapping unit 4 by acquiring the ion current intensity with mass number of 27. A quadrupole mass spectrometer (QMS) is a highly sensitive vacuum analytical instrument. Its working principle involves using an electric field to filter ions with different mass-to-charge ratios, thereby achieving qualitative and quantitative analysis of gaseous components. This mass spectrometer can be configured to be directly mounted on the vacuum chamber of the molecular beam epitaxy (MBE) device 1, and can be used through a sampling port or directly exposed to the analyte area to ionize, accelerate, separate, and detect gaseous metal atoms generated by sublimation. Indium (In), gallium (Ga), and aluminum (Al) are commonly used Group III metal sources in MBE processes. During growth, they tend to deposit on the sidewalls of the substrate heater 2, forming metal contaminants. Indium (In) exists in nature in two main stable isotopes: 113 In and 115 By simultaneously monitoring the ion current intensity of both mass numbers, In helps distinguish background noise or interfering ions and provides more comprehensive isotopic information, thereby effectively improving the accuracy and reliability of gaseous indium atom concentration measurements. Gallium (Ga) is mainly found in nature as... 69 Gallium exists in the form of Ga, therefore, the concentration of gallium atoms can be effectively represented by collecting the ion current intensity with a mass number of 69. Aluminum (Al) exists in nature in only one stable isotope: 27 Al, therefore, by collecting the ion current intensity of mass number 27, the concentration information of aluminum atoms can be directly and accurately reflected.

[0036] This embodiment introduces a quadrupole mass spectrometer as the core tool of the gaseous metal atom concentration acquisition component 7, and designs a precise concentration acquisition method for the specific properties of the metals to be cleaned, such as indium, gallium, or aluminum. Specifically, when the molecular beam epitaxy (MBE) equipment 1 is not performing any processes, the controller 6 acquires the metal type information of the metal to be cleaned and the current vacuum level of the MBE equipment 1, and determines a target temperature range based on this information. This target temperature range can induce the sublimation of the metal to be cleaned. When the radiation heating unit 3 radiates heat to the substrate heater 2, so that the sidewall temperature information is within the target temperature range, the metal to be cleaned on the sidewall of the substrate heater 2 will continue to sublimate to form gaseous atoms. At this time, the quadrupole mass spectrometer is activated, and its probe is located in the region between the substrate heater 2 and the condensation capture unit 4, enabling it to capture and analyze these gaseous metal atoms in real time. For indium, the metal to be cleaned, the quadrupole mass spectrometer simultaneously monitors the ion current intensity with mass numbers of 113 and 115. Since indium's two main isotopes correspond to these two mass numbers respectively, simultaneous monitoring can provide more comprehensive isotopic information, thereby improving the accuracy and reliability of indium atom concentration measurements and effectively distinguishing background noise or interfering ions. For gallium, a metal to be cleaned, the quadrupole mass spectrometer monitors the ion current intensity at mass number 69 because... 69 Ga is the main isotope of gallium, and its high abundance means that the ion current intensity at this mass number accurately reflects the concentration of gallium atoms. For aluminum, a metal to be cleaned, the quadrupole mass spectrometer monitors the ion current intensity at a mass number of 27 because... 27 Al is the only stable isotope of aluminum, therefore the ion current intensity at this mass number can directly and accurately reflect the concentration of aluminum atoms. In this way, the quadrupole mass spectrometer can accurately identify and quantify the concentration information of specific metal atoms. This real-time concentration information is then transmitted to the controller 6. In the presence of multiple metals to be cleaned, the controller 6 obtains the corresponding preset concentration threshold based on the metal to be cleaned within the currently selected target temperature range. The controller 6 uses the radiation heating unit 3 to maintain the sidewall temperature information within the currently selected target temperature range and continuously analyzes whether the sidewall temperature information is maintained within the target temperature range for a preset duration, and whether the concentration of gaseous atoms formed by the sublimation of the metal to be cleaned corresponding to the currently selected target temperature range is less than the preset concentration threshold. Only when both conditions are met is the cleaning of the current metal considered basically complete, and subsequent steps are executed. This cleaning judgment mechanism based on real-time concentration feedback significantly improves the intelligence and accuracy of the cleaning process, avoiding the problems of incomplete or over-cleaning that may result from judging solely by time or temperature. The condensation capture unit 4, operating at a low temperature, efficiently captures these sublimated gaseous metal atoms, preventing them from redepositing or contaminating other areas.

[0037] Preferably, in order to improve the detection sensitivity of the quadrupole mass spectrometer for aluminum, gallium, and indium, this embodiment pre-tunes the quadrupole mass spectrometer. The pre-tuning process specifically includes: ① Basic preparation and background detection: a. Ensure that the MBE system is under ultra-high vacuum background (e.g., ≤5×10⁻⁶). -8 a. Turn off all source furnaces; b. Start QMS and perform the factory-preset automatic tuning or manually set a broad initial parameter; c. In full-spectrum scan mode (e.g., 1-200 amu), record the background mass spectrum and confirm that there are no significant interference peaks near the target mass numbers (27, 69, 113, and 115). ② Turn on only one source at a time and ensure that the beam intensity is moderate. Perform calibration and optimization for each metal source. The calibration and optimization process for each metal source is similar. The calibration and optimization process for the indium metal source includes: a. Heating the indium source furnace to a preset temperature that produces a weak and stable beam (this temperature can make the metal beam emitted by the indium source furnace 10 -8 (Torrent temperature is much lower than the epitaxial growth temperature) so that the metal beam emitted from the indium source furnace can be clearly distinguished by QMS; b. In the QMS software, switch the monitoring mode to single-ion monitoring and add the first In... + For the channel (mass number 115), fine-tune the ion source electron energy, lens voltage, and quadrupole resolution parameters of the QMS until the signal with a mass number of 115 reaches its maximum and most stable state. Record this set of parameters as the first In optimization parameters; c. Add the second In. + For the channel (mass number 113), finely adjust the ion source electron energy, lens voltage, and quadrupole resolution parameters of the QMS until the signal with a mass number of 113 reaches its maximum and most stable state. Record this set of parameters as the second In optimization parameters. ③ Parameter integration and cleaning mode creation: a. In the QMS control software, create a dedicated detection method called "In-situ Cleaning Monitoring" to integrate the optimized Al... + Ga + In + The SIM channel is integrated into the method and associated with its corresponding optimized parameters; b. Simultaneously, all three metal sources are weakly turned on, and the detection method is run to confirm that the signals of the three channels can be clearly, synchronously, and stably monitored without crosstalk. At this point, the QMS is considered to have been tuned. Specifically, the process of adjusting the electron energy is as follows: scan the electron energy from low to high (typically 20–100 eV) to find the target metal ion (such as In). +The optimal operating value for the strongest and most stable signal is selected to efficiently ionize the target metal atoms while avoiding the influence of background gases. The process of adjusting the lens voltage includes: changing the focusing / extraction lens voltage in preset steps (e.g., ±5V steps), observing changes in signal intensity, and locking the voltage value corresponding to the signal peak to efficiently focus scattered ions within the ionization cell and push them into the quadrupole, maximizing ion transport efficiency. The specific process of adjusting the quadrupole resolution includes: adjusting the DC / RF voltage ratio (i.e., the mass peak width), gradually narrowing the mass peak while ensuring a sufficient signal-to-noise ratio, so that the valley depth between adjacent mass numbers is less than 80% of the peak height, to achieve the best balance between signal purity and intensity.

[0038] In some preferred embodiments, step A4 includes: A41. Use the median value of the currently selected target temperature range as the preset reference temperature; A42. The PID controller adjusts the heating power of the radiant heating unit 3 according to the side wall temperature information and the preset reference temperature to maintain the side wall temperature information within the currently selected target temperature range until the side wall temperature information is maintained within the target temperature range for a preset duration.

[0039] When cleaning specific metal contaminants, the condensation capture unit 4 switches to a low-level operating state, and the radiation heating unit 3 radiates heat to the substrate heater 2. To ensure the stability and efficiency of the cleaning process, the solution in this application sets the median of the currently selected target temperature range as the preset reference temperature, providing a clear and stable center point for temperature control. The preset reference temperature is a target temperature value set during the cleaning process to achieve precise temperature control. This temperature value serves as the benchmark for the PID controller, ensuring that the actual temperature of the sidewall of the substrate heater 2 can be stably maintained within the target temperature range. Its function is to provide a clear control center for the temperature control system, avoiding frequent temperature fluctuations at the edges of the target range, thereby improving the stability and accuracy of temperature control. In step A42, based on the PID controller, the system can precisely adjust the heating power of the radiant heating unit 3 according to the deviation between the real-time acquired sidewall temperature information and the preset reference temperature. The PID controller is a feedback controller widely used in industrial control. Its name comes from its three basic control modes: proportional, integral, and derivative. The controller 6 calculates the error between the setpoint (i.e., the preset reference temperature) and the process variable (i.e., the sidewall temperature information), and adjusts the control output (i.e., the heating power of the radiant heating unit 3) according to the weighted sum of the proportional, integral, and derivative terms. In this way, the PID controller can achieve precise, stable, and rapid temperature control. The heating power of the radiant heating unit 3 refers to the heat intensity applied by the radiant heating unit 3 to the sidewall of the substrate heater 2. By adjusting the heating power, the heating rate and the final temperature reached of the sidewall of the substrate heater 2 can be controlled. The method of adjusting the heating power depends on the specific type of the radiant heating unit 3. For example, if the radiant heating unit 3 is an infrared radiation heating gun, its heating power can be achieved by adjusting the supply voltage, current, or duty cycle of the pulse width modulation (PWM) signal. The controller 6 precisely adjusts the heating power of the radiant heating unit 3 according to the output signal of the PID controller, so as to ensure that the side wall temperature information can be stably maintained near the preset reference temperature, thereby keeping it within the target temperature range.

[0040] This feedback regulation mechanism based on a PID controller allows the temperature of the sidewall of substrate heater 2 to be dynamically and precisely maintained within the currently selected target temperature range. The PID controller responds promptly to temperature changes, quickly eliminating temperature deviations and suppressing temperature fluctuations through proportional, integral, and derivative actions, thereby ensuring that the metal to be cleaned sublimates continuously and stably within the optimal sublimation temperature range. This precise temperature control not only guarantees the efficiency of metal contaminant sublimation, avoiding situations where metal contaminants cannot sublimate smoothly due to excessively low temperatures, resulting in ineffective cleaning of metal contaminants deposited on the sidewall of substrate heater 2, but also avoids damage to substrate heater 2 or the cold screen due to excessively high temperatures. By stabilizing the temperature near the midpoint of the target range, the possibility of frequent temperature fluctuations at the range boundaries is reduced, further improving the reliability of the cleaning process. When the sidewall temperature information is maintained within the target temperature range for a preset duration, it indicates that the cleaning of the current metal contaminants has achieved the expected effect, and the system will proceed to the next stage of cleaning or complete the entire cleaning process. This sophisticated temperature control strategy enables the entire in-situ cleaning system to achieve more efficient, thorough, and safer cleaning results when dealing with various metal contaminants, significantly improving the operating efficiency and wafer quality of the molecular beam epitaxy equipment 1.

[0041] In some preferred embodiments, the condensation capture unit 4 includes a capture hood 41, a cooling medium supply assembly (not shown in the figure), and a lifting assembly 42. The lifting assembly 42 is disposed inside the molecular beam epitaxy device 1 and above the substrate heater 2. The capture hood 41 retracts upward and has an opening at its lower end. The capture hood 41 is connected to the lifting assembly 42. The lifting assembly 42 is used to drive the capture hood 41 to rise or fall, so that the condensation capture unit 4 can switch between two states: a high-position retracted state and a low-position working state. The capture hood 41 is provided with a cooling medium flow channel. The cooling medium supply assembly is connected to the cooling medium flow channel and is used to supply cooling medium to the cooling medium flow channel.

[0042] The capture hood 41 is the main structure of the condensation capture unit 4. Its function is to physically collect and condense gaseous metal atoms. The capture hood 41 can be made of a high thermal conductivity material (e.g., high-purity copper, aluminum alloy, or stainless steel), and its surface can be specially treated to enhance the condensation effect and reduce the re-evaporation of contaminants. Its shape can be designed as a truncated cone, an inverted bowl, or a bell jar to optimize the capture efficiency of sublimated gases. The cooling medium supply assembly is a device that provides a cryogenic environment for the capture hood 41 and is used to supply cooling medium to the cooling medium flow channels inside the capture hood 41. This assembly can be an independent refrigeration system, such as including a refrigerator, a circulating pump, and a cooling medium storage tank, using liquid nitrogen, liquid helium, chilled water, or ethylene glycol solution as the cooling medium. The lifting assembly 42 is a mechanical device that functions to move the capture hood 41 precisely in the vertical direction. This assembly can be implemented in various ways, such as by a lead screw mechanism driven by a stepper motor or servo motor, a pneumatic or hydraulic cylinder, or by using the principle of magnetic levitation. The lifting assembly 42 is positioned within the molecular beam epitaxy apparatus 1 and above the substrate heater 2. This arrangement ensures that the trapping shroud 41 can be raised and lowered directly and unobstructed above the substrate heater 2, effectively covering or moving away from the sidewalls of the substrate heater 2. The trapping shroud 41's upward-contracting design with an opening at the lower end allows it to effectively surround the sidewalls of the substrate heater 2 and concentrate the capture of sublimated gaseous metal atoms in its low-position operating state. In its high-position retracted state, its contracted shape minimizes interference with other components within the chamber. The connection between the trapping shroud 41 and the lifting assembly 42 ensures the stability and accuracy of the trapping shroud 41 during raising and lowering, preventing positional deviations or operational failures due to loose connections. The lifting assembly 42 drives the trapping shroud 41 to rise or fall, enabling the condensation trapping unit 4 to switch between high-position retracted and low-position operating states. This allows for precise control of the condensation trapping unit 4's position, ensuring rapid and reliable switching between cleaning and epitaxial growth modes. The capture shroud 41 is equipped with a cooling medium channel, which provides a flow path for the cooling medium, ensuring that the surface of the capture shroud 41 is uniformly and efficiently cooled, thereby effectively condensing gaseous metal atoms. The cooling medium supply component is connected to the cooling medium channel, ensuring that the cooling medium can be smoothly delivered from the supply component to the channel inside the capture shroud 41, maintaining the low temperature of the capture shroud 41. The cooling medium supply component is used to supply cooling medium to the cooling medium channel, and its function is to continuously maintain the low temperature of the capture shroud 41, enabling it to efficiently capture sublimated metal atoms.

[0043] The solution in this application employs an ingenious structural design, enabling the condensation capture unit 4 to work collaboratively with the radiation heating unit 3, temperature acquisition component 5, and controller 6 in the in-situ contaminant cleaning system of the molecular beam epitaxy (MBE) equipment, forming an efficient and reliable in-situ contaminant cleaning mechanism. When the controller 6 acquires information about the metal type of the metal to be cleaned and the current vacuum level of the MBE equipment 1, and determines the target temperature range, it first controls the lifting component 42 to drive the capture shroud 41 from its high-position retracted state to its low-position working state, so that its lower opening approaches or surrounds the sidewall of the substrate heater 2. Simultaneously, the cooling medium supply component begins supplying cooling medium to the cooling medium channels within the capture shroud 41, rapidly cooling the surface of the capture shroud 41 and forming an efficient condensation capture surface. Subsequently, the radiation heating unit 3 radiates heat to the sidewall of the substrate heater 2, ensuring that the sidewall temperature falls within the target temperature range, thus promoting the sublimation of deposited metal contaminants into gaseous atoms. These gaseous atoms diffuse upwards in the ultra-high vacuum environment inside the molecular beam epitaxy device 1 and are efficiently captured by the cryogenic trapping hood 41, condensing and depositing on its surface. The cleaning process continues until the sidewall temperature remains within the target temperature range for a preset duration. After cleaning, the controller 6 controls the radiation heating unit 3 to stop heating and stops the supply of cooling medium. When the temperature of the trapping hood 41 rises back to the second preset safe temperature, the lifting component 42 drives the trapping hood 41 to rise to the high-position retracted state, moving it away from the epitaxial growth area. This structured condensation trapping unit 4 design not only ensures the precise position and efficient cooling of the trapping hood 41 during the cleaning process, but more importantly, through the precise control of the lifting component 42, the condensation trapping unit 4 can reliably switch to the high-position retracted state after cleaning, thereby avoiding the risk of contaminants falling due to thermal expansion and other factors after cleaning, and ensuring a pure environment for subsequent epitaxial growth.

[0044] In some preferred embodiments, the ratio of the diameter of the lower opening of the capture shroud 41 to the diameter of the substrate heater 2 is 2-2.5, and the angle between the sidewall of the capture shroud 41 and the vertical line is 45-50°.

[0045] The ratio of the diameter of the lower opening of the trap shroud 41 to the diameter of the substrate heater 2 defines the relative size of the lower opening of the trap shroud 41. Its function is to ensure that the trap shroud 41 can effectively cover the contaminant sublimation area on the sidewall of the substrate heater 2, while avoiding unnecessarily large dimensions. In actual operation, the diameter of the lower opening of the trap shroud 41 that meets this ratio can be directly calculated and manufactured based on the known or preset diameter of the substrate heater 2. The angle between the sidewall of the trap shroud 41 and the vertical line defines the inclination of the sidewall of the trap shroud 41. Its function is to optimize the condensation adhesion efficiency and stability of sublimated metal atoms on the inner wall of the trap shroud 41, and to help reduce thermal stress.

[0046] This embodiment addresses the aforementioned technical problems by optimizing the geometric parameters of the trapping shroud 41, ensuring efficient contaminant capture and reducing potential risks. Specifically, in the in-situ contaminant cleaning system of a molecular beam epitaxy (MBE) device, when the controller 6 initiates the cleaning process, the condensation trapping unit 4 is driven to a low-position operating state. The lower opening of its trapping shroud 41 is located above the sidewall of the substrate heater 2, and the radiation heating unit 3 heats the sidewall of the substrate heater 2, causing the deposited metal contaminants to sublimate. This application sets the ratio of the diameter of the lower opening of the trapping shroud 41 to the diameter of the substrate heater 2 within the range of 2-2.5, ensuring that the opening size of the trapping shroud 41 can fully cover the contaminant sublimation area of ​​the sidewall of the substrate heater 2. This allows gaseous metal atoms sublimated from the sidewall of the substrate heater 2 to efficiently enter the internal space of the trapping shroud 41, avoiding the problem of sublimated atoms escaping or insufficient capture due to an excessively small opening. At the same time, this ratio also avoids the increased heat radiation loss or spatial interference with other components in the cavity that may result from an excessively large opening. Furthermore, the angle between the sidewall of the capture hood 41 and the vertical line is limited to 45-50°. This optimized tilt angle allows gaseous metal atoms entering the capture hood 41 to condense and adhere more uniformly and stably upon contact with the cooled inner wall of the capture hood 41. An appropriate tilt angle helps guide the uniform distribution of condensate, reducing local stress concentration and thus lowering the risk of condensate cracking, warping, or detachment due to mismatched thermal expansion coefficients. Through the synergistic design of the above geometric parameters, the capture hood 41 of this application can maximize the capture of sublimated metal contaminants and ensure their stable adhesion to the capture hood 41, significantly improving the efficiency and reliability of in-situ cleaning and effectively solving the problems of low contaminant capture efficiency and the risk of detachment caused by improper geometric design of the capture hood 41.

[0047] In some preferred embodiments, the radiation heating unit 3 includes an infrared radiation heating gun. The installation height of the infrared radiation heating gun is less than the height of the top surface of the substrate heater 2. The irradiation point of the infrared radiation heating gun on the substrate heater 2 is located on the side wall of the substrate heater 2. When the condensation capture unit 4 switches to the low-position working state, the height of the lower opening of the capture cover 41 is less than the height of the top surface of the substrate heater 2 and greater than the height of the irradiation point of the infrared radiation heating gun.

[0048] An infrared radiation heating gun is a heating device that uses infrared radiation as its primary heat source. Its working principle involves emitting infrared radiation of a specific wavelength, causing the irradiated object to absorb energy and heat up. Compared to other heating methods, infrared radiation heating guns offer advantages such as non-contact heating, high energy transfer efficiency, fast response speed, and ease of achieving precise localized heating. The installation height of the infrared radiation heating gun refers to its vertical position within the cavity of the molecular beam epitaxy equipment 1. Setting its installation height to be less than the top surface of the substrate heater 2 ensures that the infrared radiation heating gun can be aimed at the sidewall area of ​​the substrate heater 2 from below or to the side. This installation method allows heating energy to be effectively projected onto the sidewall of the substrate heater 2, avoiding the problem of the heating beam being blocked or energy dispersed by the substrate heater 2 body due to an excessively high installation position, thus ensuring effective heating of the target area. The irradiation point refers to the area where the infrared radiation energy emitted by the infrared radiation heating gun is most concentrated. Precisely positioning this irradiation point on the sidewall of the substrate heater 2 is crucial for efficient contaminant removal. This setup ensures that the heating energy directly acts on the area where metallic contaminants are deposited, maximizing thermal energy utilization and causing the metallic contaminants on the sidewall to quickly reach their sublimation temperature. Precise control of the irradiation point can be achieved by adjusting the tilt angle, rotation angle, and focal length of the internal optical system of the infrared radiation heating gun to ensure that the infrared radiation accurately covers the target sidewall area. When the condensation capture unit 4 is in a low-position operating state, the lower opening of the capture cover 41 is positioned above the sidewall of the substrate heater 2, but its height is lower than the top surface of the substrate heater 2. Simultaneously, the height of this opening is higher than the irradiation point of the infrared radiation heating gun on the sidewall of the substrate heater 2. This precise relative height setting serves a dual purpose: firstly, it ensures that the lower opening of the trapping shroud 41 covers the area above the sidewall of the substrate heater 2 as much as possible, so as to trap metal atoms sublimated from the sidewall and prevent them from diffusing to other areas of the cavity; secondly, by setting the lower opening of the trapping shroud 41 above the irradiation point of the infrared radiation heating gun and below the top surface of the substrate heater 2, it can prevent the trapping shroud 41 from blocking the infrared radiation emitted by the infrared radiation heating gun, thereby ensuring the smooth progress of the heating process and ensuring that the heating energy can reach the sidewall of the substrate heater 2 without obstruction.

[0049] This embodiment solves the aforementioned technical problems by refining the structure and spatial layout of the radiation heating unit 3. Specifically, the system uses an infrared radiation heating gun as the radiation heating unit 3, which, utilizing its directional radiation characteristics, can efficiently and accurately transfer heat energy to the target area. The installation height of the infrared radiation heating gun is set to be less than the height of the top surface of the substrate heater 2, ensuring that the heating gun can be aligned with the sidewall of the substrate heater 2 from below or the side, thereby concentrating the heat energy on the contaminant deposition area. Furthermore, the irradiation point of the infrared radiation heating gun is precisely positioned on the sidewall of the substrate heater 2, directly heating the area of ​​metal contaminants, greatly improving the targeting and efficiency of the heating, and promoting the effective sublimation of metal contaminants. During the cleaning process, when the condensation capture unit 4 switches to the low-position working state, the height of the lower opening of its capture cover 41 is limited to less than the height of the top surface of the substrate heater 2, but greater than the height of the irradiation point of the infrared radiation heating gun. This ingenious relative positioning design allows the trapping shroud 41 to effectively trap sublimated metal atoms without obstructing the infrared radiation emitted by the infrared heating gun. Therefore, the infrared heating gun can continuously and unimpededly heat the sidewalls of the substrate heater 2, while the condensation trapping unit 4 simultaneously and efficiently traps the sublimated metal atoms. Through these technical means, the system of this application optimizes the heating process and improves trapping efficiency based on the basic in-situ contaminant cleaning scheme. The precise heating capability of the infrared heating gun and the interference-free synergy of the trapping shroud 41 ensure the high efficiency, stability, and safety of the cleaning process. This structural optimization allows for more thorough and rapid removal of metal contaminants from the sidewalls of the substrate heater 2, effectively reducing contaminant residue, extending equipment operating cycles, and reducing the frequency of cavity cleaning.

[0050] In some preferred embodiments, there are multiple radiative heating units 3, which are arranged in a circumferential array on the molecular beam epitaxy apparatus 1. By setting multiple radiative heating units 3, the heating power can be effectively distributed, avoiding local overheating or underheating caused by a single heat source, thus laying the foundation for achieving uniform heating of the sidewalls of the substrate heater 2. The circumferential array of multiple radiative heating units 3 on the molecular beam epitaxy apparatus 1 means that these heating units are arranged uniformly or non-uniformly around the substrate heater 2. This distribution ensures uniform circumferential heating of the sidewalls of the substrate heater 2. For example, multiple radiative heating units 3 can be installed at equal angular intervals on the cavity wall of the molecular beam epitaxy apparatus 1, such as three heating units distributed at 120-degree intervals or four heating units distributed at 90-degree intervals. Through this circumferential layout, radiant energy can act uniformly on the sidewalls of the substrate heater 2 from multiple directions, directly solving the problem of uneven circumferential heating.

[0051] This embodiment solves the problem of uneven heating by setting multiple radiant heating units 3 in a circumferential array. Specifically, the use of multiple radiant heating units 3 disperses the heating power, avoiding localized hot or cold spots caused by a single heat source and ensuring more comprehensive heating coverage. The multiple radiant heating units 3 are arranged in a circumferential array on the molecular beam epitaxy device 1, allowing heating energy to uniformly surround the entire circumference of the sidewall of the substrate heater 2, achieving a balanced temperature distribution. The operational logic of this overall scheme is that when multiple radiant heating units 3 work collaboratively in a circumferential array, they collectively form a uniform radiant thermal field that can stably and uniformly act on the sidewall of the substrate heater 2. The radiant energy of each heating unit is superimposed and supplemented, thereby eliminating the temperature gradient that may be caused by a single heat source. This distributed, circumferential heating mechanism ensures that metallic contaminants on the sidewall of the substrate heater 2 can continuously sublimate in a controlled and uniform temperature environment, thus being efficiently captured by the condensation and capture unit 4. Simultaneously, due to the uniform heat distribution, unnecessary stress or damage to the equipment caused by overheating in localized areas is avoided, thereby improving the stability and safety of the cleaning process.

[0052] Secondly, such as Figure 4 As shown, this application also provides an in-situ cleaning method for contaminants in a molecular beam epitaxy (MBE) apparatus, used to clean metallic contaminants deposited on the sidewall of the substrate heater 2 in the MBE apparatus 1. Applied to the in-situ cleaning system for contaminants in the MBE apparatus provided in the first aspect, the in-situ cleaning method for contaminants in the MBE apparatus includes the following steps: S1. When the molecular beam epitaxy equipment 1 is not performing a process, acquire the metal type information of the metal to be cleaned and the current vacuum level of the molecular beam epitaxy equipment 1, and then determine the target temperature range based on the metal type information and the current vacuum level; the lower limit of the target temperature range is greater than the sublimation temperature of the metal to be cleaned under the current vacuum level, and the upper limit of the target temperature range is less than the preset recrystallization temperature corresponding to the substrate heater 2 and the first preset safety temperature corresponding to the cold screen of the molecular beam epitaxy equipment 1; S2. Control the condensation capture unit 4 to switch to the low-level working state, and control the radiation heating unit 3 to radiate heat the substrate heater 2 so that the sidewall temperature information is within the target temperature range until the sidewall temperature information is maintained within the target temperature range for a preset duration.

[0053] The in-situ cleaning method for contaminants in molecular beam epitaxy equipment provided in this embodiment is applied to the in-situ cleaning system for contaminants in molecular beam epitaxy equipment provided in the first aspect above. The principle of the in-situ cleaning method for contaminants in molecular beam epitaxy equipment provided in this embodiment is the same as that of the in-situ cleaning system for contaminants in molecular beam epitaxy equipment provided in the first aspect above, and will not be repeated here.

[0054] As can be seen from the above, the in-situ contaminant cleaning system and method for molecular beam epitaxy equipment provided in this application effectively reduces the amount of contaminant deposited on the sidewall of the substrate heater 2 by in-situ heating the substrate heater 2 when the equipment is not performing a process, causing the metal contaminants to sublimate, and using the condensation capture unit 4 to capture the sublimated metal contaminants. This reduces the number of times the cavity is opened for cleaning, thereby minimizing the damage to the vacuum environment and the introduction of additional contaminants caused by the cavity opening cleaning, and effectively improving the utilization rate of the molecular beam epitaxy equipment 1.

[0055] In the embodiments provided in this application, it should be understood that the disclosed apparatus and method can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of the above units is only a logical functional division, and there may be other division methods in actual implementation. Furthermore, multiple units or components may be combined or integrated into another robot, or some features may be ignored or not executed. Additionally, the coupling or direct coupling or communication connection shown or discussed may be through some communication interface; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0056] In this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations.

[0057] The above are merely embodiments of this application and are not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. An in-situ contaminant cleaning system for a molecular beam epitaxy (MBE) equipment, used for cleaning metallic contaminants deposited on the sidewalls of a substrate heater in a MBE equipment, characterized in that, The in-situ contaminant cleaning system for the molecular beam epitaxy equipment includes: A radiation heating unit is disposed on the molecular beam epitaxy equipment; A condensation capture unit is disposed within the molecular beam epitaxy apparatus and can switch between two states: high-position retracted and low-position operation. The distance between the condensation capture unit and the substrate heater in the high-position retracted state is greater than the distance between the condensation capture unit and the substrate heater in the low-position operation state. A temperature acquisition component is installed on the molecular beam epitaxy equipment and is used to acquire the sidewall temperature information of the substrate heater; The controller is configured to acquire the metal type information of the metal to be cleaned and the current vacuum level of the molecular beam epitaxy (MBE) equipment when no process is being performed. Then, based on the metal type information and the current vacuum level, it determines a target temperature range. The lower limit of the target temperature range is greater than the sublimation temperature of the metal to be cleaned at the current vacuum level, and the upper limit of the target temperature range is less than the preset recrystallization temperature corresponding to the substrate heater and the first preset safety temperature corresponding to the cold screen of the MBE equipment. The controller is also configured to control the condensation capture unit to switch to a low-level operating state and control the radiation heating unit to radiate heat the substrate heater so that the sidewall temperature information is within the target temperature range, until the sidewall temperature information is maintained within the target temperature range for a preset duration. Then, it controls the condensation capture unit to switch to a high-level retracted state.

2. The in-situ contaminant cleaning system for molecular beam epitaxy equipment according to claim 1, characterized in that, When multiple metals to be cleaned are present, the number of metal type information and the number of target temperature ranges are both multiple. Each type of metal to be cleaned corresponds to one metal type information and one target temperature range. The process of controlling the condensation capture unit to switch to a low-level operating state and controlling the radiation heating unit to radiate heat the substrate heater so that the sidewall temperature information is within the target temperature range, until the sidewall temperature information is maintained within the target temperature range for a preset duration, and then controlling the condensation capture unit to switch to a high-level retracted state includes: A1. Control the condensation capture unit to switch to a low-level working state; A2. Select the target temperature range with the smallest upper limit value; A3. Control the radiation heating unit to radiate heat the sidewall of the substrate heater so that the sidewall temperature information is within the currently selected target temperature range; A4. Use the radiant heating unit to maintain the sidewall temperature information within the currently selected target temperature range until the sidewall temperature information is maintained within the target temperature range for a preset duration. A5. Delete the currently selected target temperature range, and then analyze whether the target temperature range still exists. If yes, return to step A2; otherwise, proceed to step A6. A6. Control the radiant heating unit to stop radiant heating and control the condensation capture unit to stop cooling. Then, when the temperature of the condensation capture unit rises to the second preset safe temperature, control the condensation capture unit to switch to the high-level retracted state.

3. The in-situ contaminant cleaning system for molecular beam epitaxy equipment according to claim 2, characterized in that, The in-situ contaminant cleaning system of the molecular beam epitaxy equipment further includes a gaseous metal atom concentration acquisition component. This component is used to acquire the concentration information of gaseous atoms formed by the sublimation of the metal to be cleaned in the region between the substrate heater and the condensation capture unit. Step A4 includes: A41. Obtain the corresponding preset concentration threshold based on the metal to be cleaned corresponding to the currently selected target temperature range. A42. The sidewall temperature information is maintained within the currently selected target temperature range using the radiant heating unit. A43. Analyze whether the sidewall temperature information is maintained within the target temperature range for a preset duration and the concentration of gaseous atoms formed by the sublimation of the metal to be cleaned corresponding to the currently selected target temperature range is less than the preset concentration threshold. If yes, proceed to step A5; otherwise, return to step A42.

4. The in-situ contaminant cleaning system for molecular beam epitaxy equipment according to claim 3, characterized in that, The gaseous metal atom concentration acquisition component includes a quadrupole mass spectrometer. The metal to be cleaned is indium, gallium, or aluminum. The quadrupole mass spectrometer acquires the concentration information of indium in the region between the substrate heater and the condensation trapping unit by acquiring the ion current intensity of mass numbers 113 and 115. The quadrupole mass spectrometer acquires the concentration information of gallium in the region between the substrate heater and the condensation trapping unit by acquiring the ion current intensity of mass number 69. The quadrupole mass spectrometer acquires the concentration information of aluminum in the region between the substrate heater and the condensation trapping unit by acquiring the ion current intensity of mass number 27.

5. The in-situ contaminant cleaning system for molecular beam epitaxy equipment according to claim 2, characterized in that, Step A4 includes: A41. Use the median value of the currently selected target temperature range as the preset reference temperature; A42. The heating power of the radiant heating unit is adjusted by the PID controller according to the sidewall temperature information and the preset reference temperature, so as to maintain the sidewall temperature information within the currently selected target temperature range until the sidewall temperature information is maintained within the target temperature range for a preset duration.

6. The in-situ contaminant cleaning system for molecular beam epitaxy equipment according to claim 1, characterized in that, The condensation capture unit includes a capture hood, a cooling medium supply assembly, and a lifting assembly. The lifting assembly is disposed within the molecular beam epitaxy equipment and above the substrate heater. The capture hood retracts upward and has an opening at its lower end. The capture hood is connected to the lifting assembly. The lifting assembly is used to drive the capture hood to rise or fall, thereby switching the condensation capture unit between two states: a high-position retracted state and a low-position working state. The capture hood has a cooling medium flow channel, and the cooling medium supply assembly communicates with the cooling medium flow channel, supplying cooling medium to the cooling medium flow channel.

7. The in-situ contaminant cleaning system for molecular beam epitaxy equipment according to claim 6, characterized in that, The ratio of the diameter of the lower opening of the capture shroud to the diameter of the substrate heater is 2-2.5, and the angle between the sidewall of the capture shroud and the vertical line is 45-50°.

8. The in-situ contaminant cleaning system for molecular beam epitaxy equipment according to claim 6, characterized in that, The radiation heating unit includes an infrared radiation heating gun. The installation height of the infrared radiation heating gun is less than the height of the top surface of the substrate heater. The irradiation point of the infrared radiation heating gun on the substrate heater is located on the side wall of the substrate heater. When the condensation capture unit switches to the low-position working state, the height of the lower opening of the capture cover is less than the height of the top surface of the substrate heater and greater than the height of the irradiation point of the infrared radiation heating gun.

9. The in-situ contaminant cleaning system for molecular beam epitaxy equipment according to claim 1, characterized in that, The number of radiation heating units is multiple, and the multiple radiation heating units are distributed in a circumferential array on the molecular beam epitaxy device.

10. A method for in-situ cleaning of contaminants in a molecular beam epitaxy (MBE) apparatus, used to clean metallic contaminants deposited on the sidewalls of a substrate heater in a MBE apparatus, characterized in that, In the in-situ contaminant cleaning system for molecular beam epitaxy equipment as described in any one of claims 1-9, the in-situ contaminant cleaning method for molecular beam epitaxy equipment includes the following steps: S1. When the molecular beam epitaxy (MBE) equipment is not performing a process, acquire the metal type information of the metal to be cleaned and the current vacuum level of the MBE equipment, and then determine a target temperature range based on the metal type information and the current vacuum level; the lower limit of the target temperature range is greater than the sublimation temperature of the metal to be cleaned at the current vacuum level, and the upper limit of the target temperature range is less than the preset recrystallization temperature corresponding to the substrate heater and the first preset safety temperature corresponding to the cold screen of the MBE equipment; S2. Control the condensation capture unit to switch to a low-level working state, and control the radiation heating unit to radiate heat the substrate heater so that the sidewall temperature information is within the target temperature range, until the sidewall temperature information is maintained within the target temperature range for a preset duration.

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