Growth device of monocrystal diamond

Abstract

The invention provides a growth device of single crystal diamond. The device comprises a microwave resonant cavity; the fixed water-cooling substrate table is arranged in the microwave resonant cavity; the movable substrate cover is provided with an opening, the fixed water-cooling substrate table extends into the opening, so that the movable substrate cover covers the fixed water-cooling substrate table, and a through hole is formed in the top wall of the movable substrate cover so as to allow the monocrystal diamond to pass through and be in contact with the fixed water-cooling substrate table; the monitoring system is at least used for monitoring the growth temperature, the plasma state parameters and the growth thickness of the monocrystal diamond; the moving mechanism is used for enabling the movable substrate cover to move vertically; the control system is used for receiving signals of the monitoring system and controlling movement of the moving mechanism based on the signals. The growth environment of the single crystal diamond is monitored through the monitoring system, the control system controls the moving mechanism based on the monitored growth conditions, and the moving mechanism drives the movable substrate cover to move up and down, so that the growth environment of the single crystal diamond reaches the optimal state. Therefore, the yield of the monocrystal diamond is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of diamond preparation, and in particular to a single crystal diamond growth device. BACKGROUND

[0002] Single crystal diamond is known as the ultimate semiconductor material due to its excellent mechanical, thermal, optical and electrical properties, and has important application prospects in high-end fields such as optics, medicine, detectors and semiconductors. The reserves of natural diamond are limited and cannot meet the demand. At present, the main preparation methods of artificial diamond are high temperature and high pressure method (HPHT method) and microwave plasma chemical vapor deposition method (MPCVD method). Among them, the HPHT method has limitations in impurity control and product size, therefore, the preparation of high-quality and large-size single crystal diamond mainly relies on the MPCVD method.

[0003] However, the existing MPCVD technology still faces important challenges in preparing high-quality and large-size single crystal diamond. The method has extremely strict requirements for the temperature field distribution in the reaction chamber, especially the surface of the fixed substrate table, and the plasma flow field distribution after ionization of the reaction gas (such as carbon source, hydrogen, etc.). Small deviations will cause an increase in internal defects, stress, and uneven growth rate of the crystal. It is particularly important that during the long-time growth process of the traditional fixed substrate table using the MPCVD technology, the edge region of the single crystal diamond substrate will inevitably have non-epitaxial polycrystalline diamond parasitic growth (i.e., "edge polycrystalline ring") due to edge effect, and with the extension of the growth time, the edge polycrystalline ring gradually spreads to the center and outside of the single crystal diamond substrate. This phenomenon not only directly leads to the deterioration of the growth quality of the target single crystal region, but also seriously restricts the preparation of large-size and high-integrity single crystal diamond, and significantly reduces the overall single crystal diamond growth efficiency. SUMMARY

[0004] Therefore, the present application provides a single crystal diamond growth device, which adjusts the position of the movable substrate cover based on the growth environment of the single crystal diamond, so that the growth environment of the single crystal diamond is more superior, thereby improving the growth efficiency and yield of the single crystal diamond.

[0005] In order to achieve the above purpose, the present application provides the following technical solutions: A single crystal diamond growth device, comprising: a microwave resonant cavity; a fixed water-cooled substrate table arranged in the microwave resonant cavity; The mobile substrate cover is provided with an opening, and the fixed water-cooled substrate table is inserted into the opening, so that the mobile substrate cover covers the fixed water-cooled substrate table, and a through hole is arranged on the top wall of the mobile substrate cover to allow the single crystal diamond to pass through and contact the fixed water-cooled substrate table. The monitoring system is used to monitor at least the growth temperature, plasma state parameters and growth thickness of the single crystal diamond. The moving mechanism is used to drive the vertical movement of the mobile substrate cover. The control system is used to receive the signals of the monitoring system and control the movement of the moving mechanism based on the signals.

[0006] Optionally, in the single crystal diamond growth device, the monitoring system comprises: The plasma emission spectrometer is used to detect the active group composition and content in the plasma above the mobile substrate cover. The laser interferometer thickness gauge is used to measure the thickness of the single crystal diamond. The thermocouple is used to monitor the growth temperature of the single crystal diamond.

[0007] Optionally, in the single crystal diamond growth device, the moving mechanism comprises: The programmable vacuum stepper motor. The eccentric wheel is arranged on the side wall of the fixed water-cooled substrate table and in contact with the opening wall surface of the mobile substrate cover. The programmable vacuum stepper motor has a programming control function and can drive the eccentric wheel to rotate and transmit the rotary motion to the opening wall surface of the mobile substrate cover, so as to accurately control the vertical movement of the mobile substrate cover, and the electromagnetic self-locking characteristic of the programmable vacuum stepper motor is used to stably maintain the eccentric wheel at a specified position after the eccentric wheel stops rotating.

[0008] Optionally, in the single crystal diamond growth device, the thermocouples are arranged in an array on the fixed water-cooled substrate table.

[0009] Optionally, in the single crystal diamond growth device, a structure hole is arranged on the mobile substrate cover, and the structure hole is in communication with the through hole, so that the laser emitted by the laser interferometer thickness gauge passes through the structure hole and irradiates the single crystal diamond to monitor the thickness of the single crystal diamond.

[0010] Optionally, in the single crystal diamond growth device, the moving mechanism comprises at least two oppositely arranged moving mechanisms.

[0011] Optionally, in the single crystal diamond growth device, the fixed water-cooled substrate table is internally hollow and sealed, and the liquid inlet pipe and the liquid outlet pipe connected with the liquid inlet pipe are arranged in the hollow sealed structure. The control system adjusts the flow rate and temperature of the liquid inlet pipe and the liquid outlet pipe based on the feedback information of the thermocouple.

[0012] Optionally, in the single crystal diamond growth device, the control system further comprises: A flow controller is arranged to adjust the type, proportion and flow rate of the gas for generating the plasma.

[0013] The single crystal diamond growth device provided by the present application monitors the growth environment of the single crystal diamond, such as the temperature, the plasma state parameters and the growth thickness of the single crystal diamond, through the monitoring system, and the above information is transmitted to the control system, and the control system controls the moving mechanism based on the monitored information, and the moving mechanism drives the movable substrate cover to move up and down, so that the growth environment of the single crystal diamond on the fixed water-cooled substrate table reaches the best state of the single crystal diamond, that is, the temperature and the plasma state parameters are more in line with the current growth requirements of the single crystal diamond, so as to improve the growth efficiency and yield of the single crystal diamond. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of the provided drawings.

[0015] Fig. 1 The partial structure schematic diagram of the single crystal diamond growth device provided by the present application; Fig. 2 The structure schematic diagram of the single crystal diamond growth device provided by the present application; Fig. 3 The structure schematic diagram of the structure hole position provided by the present application.

[0016] 1, fixed water-cooled substrate table; 2, movable substrate cover; 3, through hole; 4, single crystal diamond; 5, thermocouple; 6, program-controlled vacuum stepping motor; 7, eccentric wheel; 8, reaction cavity bottom plate; 9, microwave resonant cavity; 10, structure hole; 11, liquid inlet pipe; 12, liquid outlet pipe. DETAILED DESCRIPTION

[0017] The application provides a single crystal diamond growth device which adjusts the position of a movable substrate cover based on the growth environment of the single crystal diamond, so that the growth environment of the single crystal diamond is more superior, and thus the growth efficiency and yield of the single crystal diamond are improved.

[0018] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative effort fall within the protection scope of the application.

[0019] As shown in Figs. 1-3 The application provides a single crystal diamond growth device, which comprises a microwave resonance cavity 9, a fixed water-cooled substrate table 1 arranged on the microwave resonance cavity 9, a movable substrate cover 2 provided with an opening, the movable substrate cover 2 is inserted into the opening through the fixed water-cooled substrate table 1, so that the movable substrate cover 2 covers the fixed water-cooled substrate table 1, and a through hole 3 is arranged on the top wall of the movable substrate cover 2 to allow the single crystal diamond 4 to pass through and contact the fixed water-cooled substrate table 1, that is, the bottom of the single crystal diamond 4 contacts the fixed water-cooled substrate table 1, a monitoring system for monitoring at least the growth temperature, plasma state parameters and growth thickness of the single crystal diamond 4, a moving mechanism for driving the vertical movement of the movable substrate cover 2, and a control system for receiving signals of the monitoring system and controlling the movement of the moving mechanism based on the signals.

[0020] More specifically, the high-precision monitoring system is used to collect and monitor the key process parameters in the growth process of the single crystal diamond 4 in real time, including the temperature distribution in the reaction chamber, the plasma state parameters (plasma active group types, content, electron temperature, etc.) excited by the microwave, and the real-time growth thickness of the single crystal diamond 4. These real-time monitoring data are continuously fed back to the control system through a high-speed data transmission channel. The control system analyzes and judges the collected data according to a preset growth process curve or a self-adaptive algorithm, and dynamically adjusts the operation parameters (such as moving speed, displacement, acceleration, etc.) of the moving mechanism. The moving mechanism drives the movable substrate cover 2 to move up and down in the vertical direction accordingly. By adjusting the position of the movable substrate cover 2, the airflow distribution, heat field distribution and active group transport efficiency in the reaction chamber can be dynamically optimized, so that the single crystal diamond 4 on the fixed water-cooled substrate table 1 is always in the best growth environment.

[0021] This closed-loop feedback control mechanism enables the actual temperature field and plasma state to more accurately match the ideal requirements of the current growth stage (such as nucleation, initial growth, stable growth, etc.), effectively reducing stress accumulation, defect formation and non-uniformity during growth, and ultimately significantly improving the quality and growth stability of single crystal diamond 4, and improving its yield.

[0022] Among them, the monitoring system includes: a plasma emission spectrometer for detecting the active group composition and content in the plasma above the movable substrate cover 2; a laser interferometer thickness gauge for measuring the thickness of the single crystal diamond 4; a thermocouple 5 for monitoring the growth temperature of the single crystal diamond 4.

[0023] Thus arranged, firstly, through multi-parameter synchronous monitoring, the key physical and chemical states in the growth environment of the single crystal diamond 4 are comprehensively mastered to provide reliable data support for process control; secondly, real-time data such as plasma composition, growth thickness and temperature are fed back to the control system, enabling the system to dynamically adjust process parameters according to the actual growth state, avoiding the lag and blindness of traditional fixed program control; thirdly, based on the monitoring data, the position of the movable substrate cover 2 is adjusted to actively regulate the plasma distribution, thermal field uniformity and reactant transport efficiency in the reaction chamber, so that the temperature, plasma activity and other parameters more accurately match the requirements of different growth stages (such as high carbon activity during nucleation period and stable thermal field during growth period), thereby reducing defect formation; fourthly, the monitoring system provides a data basis for process database establishment and intelligent control algorithm training, which is conducive to realizing batch and automated production of high-quality single crystal diamond 4, and ultimately greatly improving the yield and production efficiency.

[0024] In other optional embodiments, the laser interferometer thickness gauge can be replaced by an optical interferometer, a laser reflection or a quality monitoring system; the thermocouple 5 can be replaced by a combination of the thermocouple 5 and an infrared temperature measuring instrument.

[0025] In optional embodiments, the moving mechanism includes: a programmable vacuum stepper motor 6; an eccentric wheel 7 arranged on the side wall of the fixed water-cooled substrate table 1 and in contact with the opening wall surface of the movable substrate cover 2; wherein the programmable vacuum stepper motor 6 has a programming control function and can drive the eccentric wheel 7 to rotate, and the rotary motion is transmitted to the opening wall surface of the movable substrate cover 2, thereby accurately controlling the vertical movement of the movable substrate cover 2, and after the eccentric wheel 7 stops rotating, the electromagnetic self-locking property of the programmable vacuum stepper motor 6 is used to stably maintain the eccentric wheel 7 at the specified position.

[0026] Among them, the programmable vacuum stepper motor has small volume, can operate in a vacuum environment, and can withstand a high temperature of 250°C.

[0027] More specifically, the eccentric wheel 7 is installed on the program-controlled vacuum stepping motor 6 through a key and a shaft retaining ring, and the eccentric wheel 7 is tangent to the opening wall surface of the movable substrate cover 2. In this way, through the programming control function of the program-controlled vacuum stepping motor 6, the rotation angle of the eccentric wheel 7 can be accurately adjusted. Since the eccentric wheel 7 is in direct contact with the opening wall surface of the movable substrate cover 2, its rotational movement can be efficiently converted into vertical movement of the movable substrate cover 2, thereby achieving precise control of the position of the movable substrate cover 2.

[0028] In addition, after the eccentric wheel 7 stops rotating, the electromagnetic self-locking characteristic of the program-controlled vacuum stepping motor 6 can be used to stably maintain the eccentric wheel 7 at a specified position. This ensures that the position of the movable substrate cover 2 will not change due to external vibrations or other disturbances, ensuring the stability of the process conditions during growth, which is beneficial to improving the quality and consistency of the single crystal diamond 4.

[0029] Among them, since the program-controlled vacuum stepping motor 6 and the eccentric wheel 7 are combined for transmission, the structure is relatively simple and reliable, reducing complex mechanical transmission components and reducing failure rate and maintenance cost.

[0030] In an optional embodiment, the thermocouples 5 are arranged in an array on the fixed water-cooled substrate table 1. Specifically, the surface of the fixed water-cooled substrate table 1 is circular, the array arrangement shape of the thermocouples 5 is approximately circular, and the thermocouples 5 are distributed near the single crystal diamond 4.

[0031] In this way, firstly, the temperature distribution of the surface and near-surface area of the fixed water-cooled substrate table 1 is comprehensively obtained, avoiding local deviation caused by single-point temperature measurement, and truly reflecting the thermal field uniformity of the entire growth area, that is, achieving multi-point accurate monitoring of the temperature field; secondly, through real-time collection and comparative analysis of multi-point temperature data, the control system can identify temperature gradients or local overheating / overcooling areas, and then adjust the cooling water (to be described later) flow rate or the position of the movable substrate cover 2, achieving dynamic optimization and uniformization control of the growth area temperature field, which is beneficial to obtaining high-quality single crystal diamond 4; thirdly, when the temperature of a certain point abnormally rises or the temperature difference with other points is too large, the control system can issue a warning in a timely manner to prevent the fixed water-cooled substrate table 1 from overheating and causing damage or safety accidents, thereby improving the reliability and safety of system operation.

[0032] In an optional embodiment, it further includes a flow controller for adjusting the gas type, proportion and flow rate of the plasma. The flow controller is preferably a gas mass flow controller.

[0033] Among them, multiple gas inlet paths are provided at the top of the microwave resonance cavity 9, each path is controlled by a high-precision gas mass flow controller, and the control system adjusts the flow rate of the corresponding path based on the parameters monitored by the monitoring system.

[0034] More specifically, the flow controller (such as a mass flow controller, MFC) is used to accurately adjust the flow and mixing ratio of the process gas (such as carbon-containing gas, hydrogen, etc.) into the reaction chamber, and by dynamically adjusting the gas flow and speed, the plasma density, active group concentration and chemical ratio of the growth environment can be optimized to meet the process requirements of different growth stages.

[0035] In optional embodiments, the microwave resonant cavity 9 includes a reaction cavity bottom plate 8 for supporting the fixed water-cooled substrate table 1; the plasma emission spectrometer is arranged outside the microwave resonant cavity 9, and uses a high-precision grating to monitor the plasma state above the substrate table through the visual flange opening on the microwave resonant cavity 9.

[0036] More specifically, the reaction cavity bottom plate 8 is used to support the fixed water-cooled substrate table 1, and provides a stable foundation for the entire growth system; the microwave resonant cavity 9 is arranged outside the movable substrate cover 2, forming a closed space. In this way, the influence of the external environment on the inside of the reaction cavity can be effectively prevented, such as the invasion of dust, moisture and other pollutants, ensuring the purity of the growth environment. In addition, the microwave resonant cavity 9 also provides physical protection to prevent accidental damage to internal components of the equipment, and more importantly, maintains the growth environment of the single crystal diamond 4 in a vacuum state.

[0037] In optional embodiments, the movable substrate cover 2 is provided with a structural hole 10, which is in communication with the through hole 3, so that the laser emitted by the laser interferometer thickness gauge passes through the structural hole 10 and irradiates the single crystal diamond 4 to monitor the thickness of the single crystal diamond 4.

[0038] Specifically, the laser interferometer thickness gauge is arranged outside the microwave resonant cavity 9, and its monitoring light path passes through the visual flange opening and the structural hole 10 on the microwave resonant cavity 9 to monitor the thickness information of the single crystal diamond.

[0039] In optional embodiments, the moving mechanism includes at least two oppositely arranged moving mechanisms, so that the movable substrate cover 2 is driven by symmetrical driving forces on both sides during lifting, effectively avoiding the phenomena of unbalanced load, tilting or jamming caused by unilateral driving, ensuring smooth movement of the cylinder, good synchronization, and improving the straightness and repeat positioning accuracy of vertical movement.

[0040] In other optional embodiments, the moving mechanism can also be provided with 3 or 4, and the specific number is determined according to actual needs.

[0041] In an optional embodiment, the fixed water-cooled substrate table 1 is internally hollow and sealed, and a liquid inlet pipe 11 and a liquid outlet pipe 12 connected to the liquid inlet pipe 11 are arranged in the hollow sealed structure; wherein the control system adjusts the flow rate and temperature of the liquid inlet pipe 11 and the liquid outlet pipe 12 based on the feedback information of the thermocouple 5. It should be noted that the liquid in the liquid inlet pipe 11 and the liquid outlet pipe 12 is used for circulating cooling of the fixed water-cooled substrate table 1.

[0042] The control system adjusts the flow rate and temperature of the liquid inlet pipe 11 and the liquid outlet pipe 12 based on the feedback information of the thermocouple 5, so that the cooling water flow rate can be automatically adjusted according to the actual temperature deviation: when the local temperature is too high, the cooling water flow rate is increased to enhance heat dissipation; when the temperature is too low or tends to be ideal, the flow rate is appropriately reduced to avoid excessive cooling, and high-precision dynamic control of the growth area temperature is achieved.

[0043] In an example, the program-controlled vacuum stepper motor 6 is fixed on the reaction cavity bottom plate 8 by screws and connected to the eccentric wheel 7 by a pin; the eccentric wheel 7 is tangent to the bottom of the movable substrate cover 2 and rotates at a small angle under the drive of the program-controlled vacuum stepper motor 6, and drives the movable substrate cover 2 to move up and down with micron-level precision; the upper surface of the fixed water-cooled substrate table 1 is internally arranged with an array of thermocouples 5; the single crystal diamond 4 is placed in the through hole 3 of the top wall of the top of the movable substrate cover 2, and the bottom of the single crystal diamond 4 is in close contact with the top of the fixed water-cooled substrate table 1, and its temperature can be monitored in real time by the array of thermocouples 5; the thickness of the single crystal diamond 4 is detected by a laser interference thickness gauge through a structural hole 10 opened in the side wall of the movable substrate cover 2; a microwave plasma is above the movable substrate cover 2, and its state can be monitored in situ by a plasma emission spectrometer; the program-controlled vacuum stepper motor 6, the laser interference thickness gauge, and the plasma emission spectrometer are connected to the control system, and the program-controlled vacuum stepper motor 6 rotates under the instruction of the control system.

[0044] The basic principles of the present application are described above in conjunction with specific embodiments, but it should be noted that the advantages, advantages, effects, etc. mentioned in the present application are only examples and not limitations, and these advantages, advantages, effects, etc. cannot be considered as the must-have of each embodiment of the present application. In addition, the above specific details are only for the purpose of example and understanding, and the above details do not limit the present application to the above specific details.

[0045] The block diagrams of the devices, apparatuses, equipment, systems referred to in this application are only illustrative examples and are not intended to require or imply that the connection, arrangement, configuration must be as shown in the block diagrams. These devices, apparatuses, equipment, systems can be connected, arranged, configured in any way as will be appreciated by those skilled in the art. Words such as "include", "contain", "have", and the like are open-ended words, mean "including but not limited to", and can be used interchangeably with each other. The words "or" and "and" used herein mean the word "and / or", and can be used interchangeably with each other, unless the context clearly indicates otherwise. The word "such as" used herein means the phrase "such as but not limited to", and can be used interchangeably with each other.

[0046] It should also be noted that in the devices, apparatuses and boxes of the present application, each component or each step can be disassembled and / or reassembled. These disassembly and / or reassembly should be considered as equivalent solutions of the present application.

[0047] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other aspects without departing from the scope of the application. Thus, the present application is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0048] It should be understood that the adjectives "first", "second", "third", "fourth", "fifth" and "sixth" used in the embodiments of the present application are only used for more clearly describing the technical solutions and cannot be used to limit the protection scope of the present application.

[0049] The above description has been given for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A device for growing single crystal diamond, characterized by, The application relates to a microwave resonance cavity, a fixed water-cooled substrate table arranged in the microwave resonance cavity, a movable substrate cover provided with an opening, the movable substrate cover being inserted into the opening through the fixed water-cooled substrate table so that the movable substrate cover covers the fixed water-cooled substrate table, and a through hole being arranged on a top wall of the movable substrate cover to allow the single-crystal diamond to pass through and contact the fixed water-cooled substrate table, a monitoring system for monitoring at least the growth temperature, plasma state parameters and growth thickness of the single-crystal diamond, a moving mechanism for driving vertical movement of the movable substrate cover, and a control system for receiving signals of the monitoring system and controlling movement of the moving mechanism based on the signals. The monitoring system comprises a plasma emission spectrometer for detecting active group components and contents in plasma above the movable substrate cover, a laser interferometer for measuring the thickness of the single-crystal diamond, and a thermocouple for monitoring the growth temperature of the single-crystal diamond. The moving mechanism comprises a program-controlled vacuum stepping motor and an eccentric wheel arranged on a side wall of the fixed water-cooled substrate table and in contact with an opening wall surface of the movable substrate cover. The program-controlled vacuum stepping motor has a program control function and can drive the eccentric wheel to rotate and transmit the rotary motion to the opening wall surface of the movable substrate cover, so as to accurately control the vertical movement of the movable substrate cover and stably keep the eccentric wheel at a specified position by using the electromagnetic self-locking characteristic of the program-controlled vacuum stepping motor after the eccentric wheel stops rotating. The thermocouples are arranged in an array on the fixed water-cooled substrate table. A structure hole is arranged on the movable substrate cover and communicates with the through hole, so that laser emitted by the laser interferometer passes through the structure hole and irradiates the single-crystal diamond to monitor the thickness of the single-crystal diamond. The moving mechanism comprises at least two oppositely arranged components.

2. The apparatus for growing single crystal diamond according to claim 1, wherein The fixed water-cooled substrate table has a hollow sealed structure, and a liquid inlet pipe and a liquid outlet pipe connected with the liquid inlet pipe are arranged in the hollow sealed structure. The control system adjusts the flow rate and temperature of the liquid inlet pipe and the liquid outlet pipe based on feedback information of the thermocouple. The application further comprises a flow controller for adjusting the type, proportion and flow rate of gas for generating the plasma. ​ 3. The apparatus for growing single crystal diamond according to claim 1, wherein ​ ​ ​ ​ 4. The apparatus for growing single crystal diamond according to claim 2, wherein ​ 5. The apparatus for growing single crystal diamond according to claim 2, wherein ​ 6. The apparatus for growing single crystal diamond according to claim 3, wherein ​ 7. The apparatus of claim 2, wherein the apparatus is configured to grow a single crystal diamond. ​ ​ 8. The apparatus for growing single crystal diamond according to claim 1, wherein ​ ​

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