Multi-chamber growth apparatus and method

Abstract

The application provides a multi-chamber growth device and method, which comprises a reaction chamber, a heating system, an air inlet spraying system, a monitoring system and a control system, each independent chamber is respectively provided with at least one air inlet channel for conveying multiple growth sources to the corresponding independent chamber; the monitoring system is used for acquiring the actual temperature of each growth area and the actual growth rate of the epitaxial wafer on the growth substrate in real time; the control system is in communication connection with the heating system, the air inlet spraying system and the monitoring system; the control system is configured to adjust the heating power of the corresponding heating unit and / or the growth source flow into the air inlet channel based on the actual temperature and the actual growth rate, so as to maintain the growth rate of the corresponding epitaxial wafer in each growth area within a preset target range. The multi-chamber growth device and method disclosed by the application can improve the overall thickness uniformity and crystal quality consistency of the epitaxial wafer and can be used for growing gallium nitride substrates.

Description

Technical Field

[0001] This invention relates to the field of epitaxial wafer fabrication technology, and in particular to a multi-chamber growth apparatus and method. Background Technology

[0002] Gallium nitride (GaN), as an important wide-bandgap semiconductor material, is widely used in the fabrication of high-brightness light-emitting diodes (LEDs), semiconductor lasers, and high-power electronic devices. Currently, vapor phase epitaxy is the primary method for fabricating high-quality semiconductor single crystals and epitaxial wafers, encompassing hydride vapor phase epitaxy (HVPE), metal-organic chemical vapor deposition (MOCVD), and molecular beam epitaxy (MBE). Among these, HVPE technology, due to its extremely high growth rate, has become the main process for fabricating single-crystal GaN thick-film substrates.

[0003] However, during the growth of epitaxial wafers, especially when using the HVPE method for high-speed growth of GaN thick films, edge effects are unavoidable. Specifically, in the middle and later stages of epitaxial wafer growth, the lateral growth rate of the non-polar surfaces (e.g., the (10-10) surface) and semi-polar surfaces (e.g., the (10-11) surface) in the edge region of the epitaxial wafer experiences a sudden increase, significantly higher than the growth rate of the c-surface (0001) in the central region of the epitaxial wafer. This difference leads to obvious protrusions and edge-binding phenomena at the edges of the grown epitaxial wafer, severely reducing the overall crystal quality of the epitaxial wafer and causing stress concentration inside the epitaxial wafer, which in turn leads to cracks and even rupture.

[0004] Existing epitaxial equipment cannot independently adjust the temperature and growth source supply according to the growth requirements of different radial positions of the tray, which makes it difficult to suppress the edge effect during the epitaxial wafer growth process. This leads to uncontrolled edge growth (such as edge protrusion, parasitic growth, and other abnormal phenomena) during epitaxial wafer growth, and at the same time, it causes uneven epitaxial wafer thickness and poor crystal quality consistency, which cannot meet the high-quality growth requirements of large-size epitaxial wafers.

[0005] It should be noted that the above description of the background technology is only for the purpose of providing a clear and complete explanation of the technical solutions of the present invention and facilitating understanding by those skilled in the art. It should not be assumed that the above technical solutions are known to those skilled in the art simply because they have been described in the background section of the present invention. Summary of the Invention

[0006] The purpose of this invention is to disclose a multi-chamber growth apparatus and method to solve the aforementioned technical problems, especially to improve the overall thickness uniformity and crystal quality consistency of epitaxial wafers.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a multi-chamber growth apparatus and method, comprising: a reaction chamber, wherein the reaction chamber is provided with a tray for supporting a growth substrate and a plurality of sleeves, the plurality of sleeves radially dividing the reaction chamber into a plurality of independent chambers, and the surface area of ​​the tray corresponding to each of the independent chambers being divided into a plurality of growth zones; a heating system, wherein the heating system includes a plurality of independently controlled heating units, and each of the independent chambers is respectively provided with at least one of the heating units; and an air intake spray system, wherein the air intake spray system includes a plurality of independently controlled air intake channels ... an air intake spray system, wherein the air intake channels are respectively provided with at least one of the heating units; and an air intake spray system, wherein the air intake channels are respectively provided with at least one of the heating units; and an air intake spray system, wherein the air intake channels are respectively provided The system includes at least one air intake channel for supplying multiple growth sources to the corresponding independent chambers; a monitoring system for acquiring the actual temperature of each growth zone and the actual growth rate of the epitaxial wafer on the growth substrate in real time; and a control system communicatively connected to the heating system, the air intake spray system, and the monitoring system. The control system is configured to adjust the heating power of the corresponding heating unit and / or the flow rate of the growth source supplied to the air intake channel based on the actual temperature and the actual growth rate, so as to maintain the growth rate of the epitaxial wafer corresponding to each growth zone within a preset target range.

[0008] As a further improvement of the present invention, the plurality of sleeves includes a first sleeve, a second sleeve, and an outer sleeve arranged radially from the inside to the outside; the axial length of the first sleeve is less than the axial length of the second sleeve, and the axial length of the second sleeve is less than the axial length of the outer sleeve.

[0009] As a further improvement of the present invention, each of the independent chambers is provided with a horizontal partition, which is used to divide the independent chambers into a mixing chamber and a ventilation chamber that are interconnected along the axial direction; a mixing reaction zone is formed above the tray that connects each of the independent chambers; the mixing chamber is used to mix the multiple growth sources, the ventilation chamber is connected to the mixing reaction zone, the outlet of the air inlet channel is located in the mixing chamber, and the multiple growth sources are mixed in the mixing chamber and then transported to the mixing reaction zone by the ventilation chamber.

[0010] As a further improvement of the present invention, a cooling annular gap is formed between the inner circumferential surface of the reaction chamber and the outer circumferential surface of the outer sleeve; the multi-chamber growth device further includes an air curtain cooling system, which is connected to the cooling annular gap and is used to introduce cooling gas into the cooling annular gap to form a downward flowing cooling air curtain.

[0011] In a second aspect, the present invention also provides a multi-chamber external epitaxial growth method, applied to the multi-chamber growth apparatus as described in any one of the first aspects, the method comprising the following steps: A growth substrate is placed on a tray within the reaction chamber; The air intake spray system delivers multiple growth sources to each of the independent chambers, and the heating system heats each of the independent chambers. The actual growth rate of the epitaxial wafer on the growth substrate is obtained in real time through the monitoring system. The heating power of the heating unit corresponding to the independent chamber and / or the flow rate of the growth source introduced into the corresponding air intake channel are adjusted by the control system to maintain the actual growth rate of the epitaxial wafer corresponding to each growth zone within a preset target range.

[0012] As a further improvement of the present invention, the real-time acquisition of the actual growth rate of the epitaxial wafer on the growth substrate includes: the control system acquiring the actual temperature and growth source partial pressure of each growth region; wherein, the growth source partial pressure is the partial pressure of one of the multiple growth sources; the control system calculating the actual growth rate of the growth region based on the actual temperature and growth source partial pressure of the growth region; wherein, the actual growth rate increases with the increase of the actual temperature and the growth source partial pressure.

[0013] As a further improvement of the present invention, the growth zone includes a central zone, an intermediate zone, and an edge zone distributed from the inside out. The method further includes: when the control system detects that the actual growth rate of the edge zone does not fall within the preset target range, adjusting the heating power corresponding to the edge zone and detecting the adjusted actual growth rate; calculating the growth rate change rate based on the adjusted actual growth rate and the actual growth rate before adjustment; if the growth rate change rate is greater than a set value, continuing to adjust the heating power corresponding to the edge zone until the actual growth rate of the edge zone falls within the preset target range; if the growth rate change rate is less than or equal to the set value, adjusting the growth source flow rate corresponding to the edge zone until the actual growth rate of the edge zone falls within the preset target range. The actual growth rate of the edge region falls within the preset target range; or, when the control system detects that the actual growth rate of the edge region does not fall within the preset target range, it adjusts the growth source flow rate corresponding to the edge region and detects the adjusted actual growth rate; based on the adjusted actual growth rate and the actual growth rate before adjustment, it calculates the growth rate change rate; if the growth rate change rate is greater than a set value, it continues to adjust the growth source flow rate corresponding to the edge region until the actual growth rate of the edge region falls within the preset target range; if the growth rate change rate is less than or equal to the set value, it adjusts the heating power corresponding to the edge region until the actual growth rate of the edge region falls within the preset target range.

[0014] As a further improvement of the present invention, the method further includes: before the epitaxial wafer begins growth, the control system pre-determines the initial heating power of each heating unit and the initial growth source flow rate of each air intake channel, specifically including: the control system acquiring the target growth rate corresponding to each growth region; the control system determining the initial target temperature and / or the initial target growth source partial pressure corresponding to each growth region based on each target growth rate and preset process setting parameters; wherein, the preset process setting parameters include a preset process temperature or a preset growth source partial pressure; the control system determining the initial heating power corresponding to each heating unit and / or the initial growth source flow rate introduced into each air intake channel based on the initial target temperature and / or the initial target growth source partial pressure corresponding to each growth region.

[0015] As a further improvement of the present invention, the method further includes: when adjusting the heating power of the heating unit corresponding to the independent chamber, the control system calculates the maximum radial temperature difference of the tray in real time based on the actual temperature of each growth zone; the control system calculates the thermal stress generated by the epitaxial wafer in real time based on the maximum temperature difference; when the control system determines that the thermal stress reaches a preset stress threshold, it calculates the maximum safe temperature difference according to the preset stress threshold, and limits the single adjustment range of the heating power of the corresponding heating unit to a power range that ensures the maximum radial temperature difference does not exceed the maximum safe temperature difference.

[0016] As a further improvement of the present invention, the plurality of sleeves includes an outermost outer sleeve; a cooling annular gap is formed between the inner circumferential surface of the reaction chamber and the outer circumferential surface of the outer sleeve; the multi-chamber growth apparatus further includes an air curtain cooling system, which is connected to the cooling annular gap and is used to introduce cooling gas into the cooling annular gap to form a downward-flowing cooling air curtain; during the growth of the epitaxial wafer, the control system adjusts the flow rate of the cooling gas based on the current heating power of each heating unit so that the cavity wall temperature of the outer sleeve is maintained within a preset temperature range.

[0017] Compared with existing technologies, the advantages of this invention are as follows: Multiple independent chambers formed by multiple sleeves can create physical barriers between adjacent chambers, blocking the lateral diffusion of the growth source and enabling precise independent control of the growth source flow rate above each growth zone. Simultaneously, it avoids heat crosstalk between independent chambers, preventing growth runaway phenomena such as edge protrusions in the epitaxial wafer. Multiple independently controlled heating units can form mutually independent zoned temperature fields, enabling independent control of the radial temperature of each growth zone on the tray. The monitoring system can acquire the actual temperature of each growth zone and the actual growth rate of the epitaxial wafer in real time. The control system independently adjusts the corresponding heating power and / or growth source flow rate based on the feedback data, ensuring that the growth rate of each growth zone is stably maintained within the preset target range. This solves the problem of uncontrolled growth at the epitaxial wafer edges and improves the overall thickness uniformity and crystal quality consistency of the epitaxial wafer. Attached Figure Description

[0018] Figure 1 This is an overall schematic diagram of the multi-chamber growth device disclosed in this invention; Figure 2 A cross-sectional view showing multiple sleeves and trays arranged inside the reaction chamber; Figure 3 A sectional view of multiple sleeves arranged coaxially; Figure 4 This is a cloud map showing the mole fraction distribution of the group III source reactant gas delivered in the first independent chamber in the first embodiment; Figure 5 This is a cloud map showing the mole fraction distribution of the group V source gas delivered in the second independent chamber in the first embodiment; Figure 6 This is a cloud map showing the mole fraction distribution of the group III source reactant gas delivered in the first independent chamber in the second embodiment; Figure 7 This is a cloud map showing the mole fraction distribution of the group V source gas delivered in the second independent chamber in the second embodiment. Figure 8 This is a flowchart of the multi-cavity external epitaxial growth method disclosed in this invention. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent changes or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0020] The accompanying drawings in this invention are not strictly drawn to scale, and the specific dimensions of each structure can be determined according to actual needs. The drawings described in this invention are merely structural schematic diagrams. The lines shown in the accompanying drawings of this invention can be understood as components with a certain actual thickness.

[0021] Reference Figures 1 to 3 As shown, this embodiment provides a multi-chamber growth device 100, which is mainly used for the vapor deposition growth of semiconductor epitaxial wafers (such as, but not limited to, gallium nitride, silicon carbide, aluminum nitride, etc.). The multi-chamber growth device 100 includes: a reaction chamber 10, a heating system, an intake spraying system, a monitoring system, and a control system (not shown).

[0022] Inside the reaction chamber 10, there is a tray 20 for carrying the growth substrate and multiple sleeves. The multiple sleeves divide the reaction chamber 10 radially into multiple independent chambers 11. The surface area of the tray 20 corresponding to each independent chamber 11 is divided into multiple growth zones. The reaction chamber 10 is a sealed high-temperature resistant cavity, which is used to provide a sealed reaction space for the growth of epitaxial wafers. The tray 20 is horizontally arranged at the central position inside the reaction chamber 10 and is used to carry the growth substrate. In this embodiment, the multiple sleeves are preferably arranged coaxially. The multiple sleeves are arranged radially along the reaction chamber 10 to divide the reaction chamber 10 radially into multiple independent chambers 11. The surface area of the tray 20 corresponding to each independent chamber 11 is divided into multiple growth zones, and the growth zones correspond to the independent chambers 11 one by one.

[0023] The heating system includes multiple independently controlled heating units. Each independent chamber 11 is respectively provided with at least one heating unit (not shown). The heating power of each heating unit can be independently adjusted, and each heating unit can independently and precisely heat the corresponding independent chamber 11. Each independent chamber 11 forms an independent partition temperature field under the action of the corresponding heating unit, and this temperature field further acts on the corresponding growth zones on the tray 20 through thermal radiation and heat conduction; since the heating power of each heating unit can be independently adjusted and does not interfere with each other, the radial temperature partition of each growth zone on the tray 20 can be independently controlled.

[0024] The intake spraying system includes multiple independently controlled intake channels 51. Each independent chamber 11 is respectively provided with at least one intake channel 51. The intake channel 51 is used to transport multiple growth sources to the corresponding independent chamber 11. The intake channel 51 is arranged in the top spraying pipe 50 of the reaction chamber 10. The multiple mutually isolated intake channels 51 are used to independently transport different growth sources to the corresponding independent chambers 11 respectively. The flow rate of the growth source in each intake channel 51 can be independently adjusted, and can separately transport the growth source to the corresponding independent chamber 11, realizing the independent control of the growth source flow rate partition of each growth zone.

[0025] During the growth of the epitaxial wafer, the air intake channel 51 at the top of each independent chamber 11 delivers the growth source downwards. Multiple coaxially arranged sleeves form a physical barrier between adjacent independent chambers 11 to block the lateral diffusion of the growth source within each independent chamber 11. This ensures that the growth source remains radially physically isolated within each independent chamber 11, thereby achieving precise and independent control of the growth source flow rate above each growth area. At the same time, it avoids heat crosstalk between independent chambers 11 and prevents growth runaway phenomena such as edge protrusion of the epitaxial wafer.

[0026] In this embodiment, the multiple growth sources include reactant gases and carrier gases. The reactant gases include Group III source reactant gases and Group V source gases; wherein, the Group III source reactant gases preferably include gallium chloride, aluminum trichloride, or a combination thereof; and the Group V source gases preferably include ammonia. The carrier gas preferably includes nitrogen, hydrogen, or a combination thereof. Preferably, each inlet channel 51 is equipped with a mass flow controller (not shown) on its pipeline (not shown). The control system adjusts each mass flow controller to achieve precise control of the flow ratio and total flow of the reactant gas and carrier gas in each independent chamber 11.

[0027] The monitoring system is used to acquire the actual temperature of each growth zone and the actual growth rate of the epitaxial wafer on the growth substrate in real time. In this embodiment, the monitoring system includes a temperature monitoring module (not shown) and a growth rate monitoring module (not shown). The temperature monitoring module and the growth rate monitoring module are similar to related technologies and will not be described in detail here, as long as they can realize temperature detection and growth rate detection. For example, the temperature monitoring module preferably includes an in-situ optical pyrometer, which is used to acquire the actual temperature of each growth zone corresponding to the surface by detecting the thermal radiation intensity of the growth surface. The growth rate monitoring module is used to monitor the growth rate of each growth zone in real time (i.e., the real-time growth rate of the epitaxial wafer deposited layer by layer on the growth surface of the growth substrate at each growth zone on the tray 20 corresponding to each independent chamber 11, along the direction perpendicular to the growth surface). Specifically, the monitoring system can be implemented using Reflectance Anisotropy Spectroscopy (RAS) or Laser Reflectometry techniques. That is, by projecting probe light onto the growth surface and receiving the reflected signal returned by the growth surface, the actual growth rate of the epitaxial wafer corresponding to each growth region can be monitored in real time.

[0028] In this invention, the growth surface refers to the gas-solid interface located inside the reaction chamber 10 during the epitaxial wafer growth process, directly in contact with various reaction sources, and continuously undergoing vapor deposition and crystal growth. Specifically, in the initial stage of the process, the growth surface is the upper surface of the growth substrate (such as sapphire, silicon carbide, or silicon wafer); as the epitaxial deposition process continues and the epitaxial wafer thickens, the growth surface is dynamically updated to the outermost exposed surface of the epitaxial wafer.

[0029] The control system is connected to the heating system, the air intake spray system, and the monitoring system (not shown in the figure) respectively. The control system is configured to adjust the heating power of the corresponding heating unit and / or the growth source flow rate into the air intake channel 51 based on the actual temperature and actual growth rate, so as to maintain the growth rate of the epitaxial wafer corresponding to each growth region within a preset target range. During the growth of the epitaxial wafer, the control system is configured to execute the following closed-loop control logic: receive the actual temperature and actual growth rate of each growth region from the monitoring system in real time, compare the actual growth rate with the preset target range, and if the actual growth rate of any growth region deviates, independently adjust the heating power of the heating unit corresponding to that growth region, or adjust the growth source flow rate of the corresponding air intake channel 51, or adjust both simultaneously, until the actual growth rate of that growth region returns to the preset target range, thereby solving the problem of uncontrolled growth at the edge of the epitaxial wafer in the prior art and improving the overall thickness uniformity and crystal quality consistency of the epitaxial wafer.

[0030] In some examples, the parameter Figure 2 and Figure 3 As shown, the multiple sleeves include a first sleeve 31, a second sleeve 32, and an outer sleeve 33 arranged radially from the inside to the outside. The first sleeve 31 is located on the innermost side, the second sleeve 32 is sleeved on the outer side of the first sleeve 31, and the outer sleeve 33 is sleeved on the outer side of the second sleeve 32. The first sleeve 31, the second sleeve 32, and the outer sleeve 33 are arranged coaxially and spaced apart, which together divide the reaction chamber 10 radially to form multiple independent chambers 11.

[0031] Furthermore, the axial length of the first sleeve 31 is less than the axial length of the second sleeve 32, and the axial length of the second sleeve 32 is less than the axial length of the outer sleeve 33.

[0032] In some embodiments, multiple growth regions include a central region, an intermediate region, and an edge region distributed radially from the inside out. The inner circumferential surface of the first sleeve 31 encloses a first independent chamber 11a, which spatially faces and covers the central region. The outer circumferential surface of the first sleeve 31 and the inner circumferential surface of the second sleeve 32 enclose a second independent chamber 11b, which spatially faces and covers the intermediate region. The outer circumferential surface of the second sleeve 32 and the inner circumferential surface of the outer sleeve 33 enclose a third independent chamber 11c, which spatially faces and covers the edge region. Each independent chamber (i.e., 11a, 11b, 11c) is used to directionally deliver a mixed growth source containing a group III source gas (such as gallium chloride), a group V source gas (such as ammonia), and a carrier gas to the surface of the growth region it covers. Furthermore, the total flow rate of the mixed growth source entering each independent chamber and the ratio of each gas component inside can be independently adjusted and controlled by the control system.

[0033] In some embodiments, the present invention simulates the reaction source transport characteristics of two sleeve structure embodiments using computational fluid dynamics (CFD) simulation, and the results correspond to... Figures 4 to 7 .in, Figure 4 This is a mole fraction distribution cloud map of the group III source reactive gas (such as gallium chloride) transported in the first independent chamber 11a in the first embodiment (i.e., the first sleeve 31, the second sleeve 32, and the outer sleeve 33 have the same axial length). Figure 5 This is a cloud map showing the mole fraction distribution of a Group V source gas (such as ammonia) delivered in the second independent chamber 11b in the first embodiment. Figure 6 This is a cloud map showing the mole fraction distribution of the Group III source reactant gas transported in the first independent chamber 11a in the second embodiment (where the axial length of the first sleeve 31 is less than the axial length of the second sleeve 32, and the axial length of the second sleeve 32 is less than the axial length of the outer sleeve 33). Figure 7 This is a cloud map showing the mole fraction distribution of the Group V source gas delivered in the second independent chamber 11b in the second embodiment. It should be noted that, under the specific inlet conditions set in this fluid dynamics simulation, the first independent chamber 11a delivers only Group III source reactant gas, the second independent chamber 11b delivers only Group V source gas, and the third independent chamber 11c delivers only carrier gas.

[0034] Depend on Figures 4 to 7 As can be seen, in the first embodiment, the outlet heights of each sleeve are aligned, and there is a risk of upward retrograde diffusion of the V-source gas, and the uniformity of the V-source distribution on the growth surface above the tray 20 is poor. In the second embodiment, by differentiating the axial length of each sleeve, the upward retrograde diffusion of the V-source gas can be suppressed, while improving the uniformity of the V-source distribution on the growth surface.

[0035] During the actual transport of the reaction source, since the innermost first sleeve 31 has the shortest axial length, the group III source reaction gas (corresponding to) transported by the first independent chamber 11a is... Figure 6 The high-concentration gallium chloride distribution in the central region is first released between the tray 20 and the first sleeve 31. After flowing downwards a predetermined longitudinal distance, the group III source gas meets the group V source gas (corresponding to) transported in the second independent chamber 11b at the bottom outlet of the second sleeve 32. Figure 7 The high-concentration ammonia gas distribution on the left and right sides converges. The height difference between the first sleeve 31 and the second sleeve 32 allows the initially released Group III source reactant gas to pre-form a stable downward laminar flow (corresponding to...). Figure 6 The uniform flow field of gallium chloride downwards along the central region). When the group V source gas is released from the bottom outlet of the second sleeve 32, the flow direction of the group V source gas is restricted to downward movement due to the directional traction effect generated by the downward laminar flow (corresponding to...). Figure 7 (The ammonia gas does not travel upwards in reverse but only downwards) to block the diffusion path of the group V source gas into the first independent chamber 11a in reverse upwards, thereby achieving the isolation of the group III source reaction gas and the group V source gas and avoiding premature mixing of the group III source reaction gas and the group V source gas to prevent gas-phase parasitic reactions.

[0036] Meanwhile, because the outer sleeve 33 has the longest axial length, the carrier gas released from the third independent chamber 11c is at a lower release height than the group III source reactant gas in the first independent chamber 11a and the group V source gas in the second independent chamber 11b. The carrier gas is released at the position closest to the growth surface. The carrier gas flows downwards along the outer side of the second independent chamber 11b, forming a continuous annular aerodynamic barrier in the edge region. This aerodynamic barrier prevents the group III source reactant gas and group V source gas from escaping to the sidewall of the reaction chamber 10, while simultaneously creating a radially inward aerodynamic constraint on the group III source reactant gas and group V source gas, causing the group V source gas output from the second independent chamber 11b to undergo sufficient and uniform lateral diffusion in the middle region (corresponding to...). Figure 7 The ammonia molar fraction above the middle tray 20 uniformly covers the entire growth surface, and the distribution consistency between the central and edge areas is significantly improved compared to the first embodiment, thereby covering the entire growth surface and solving the technical problem of uneven distribution of group V source gas on the growth surface.

[0037] In some examples, the vertical distance between the bottom end of the first sleeve 31 and the upper surface of the growth substrate is set to be in the range of 10 mm to 30 mm. Exemplarily, the vertical distance between the bottom end of the first sleeve 31 and the upper surface of the growth substrate can be an integer such as 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, or 30 mm, or a non-integer, or a range defined by at least two integers or non-integers.

[0038] In some examples, the difference in axial length between the first sleeve 31 and the second sleeve 32 is set to be in the range of 5 mm to 20 mm. Exemplarily, the difference in axial length between the first sleeve 31 and the second sleeve 32 can be an integer such as 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, or 20 mm, or a non-integer, or a range defined by at least two integers or non-integers.

[0039] In some examples, the axial length difference between the second sleeve 32 and the outer sleeve 33 is set to be in the range of 5 mm to 20 mm. Exemplarily, the axial length difference between the second sleeve 32 and the outer sleeve 33 can be an integer such as 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, or 20 mm, or a non-integer, or a range defined by at least two integers or non-integers.

[0040] In some examples, the parameter Figure 2 and Figure 3 As shown, each independent chamber 11 is equipped with a horizontal partition 13, which is used to divide the independent chamber 11 into a mixing chamber 111 and a ventilation chamber 112 that are connected to each other along the axial direction. A mixing reaction zone 12 is formed above the tray 20, which connects each independent chamber 11. The mixing chamber 111 is used to mix multiple growth sources (such as group III source reaction gas, group V source gas and carrier gas). The ventilation chamber 112 is connected to the mixing reaction zone 12. The outlet of the air inlet channel 51 is located in the mixing chamber 111. After the multiple growth sources are mixed in the mixing chamber 111, they are transported to the mixing reaction zone 12 by the ventilation chamber 112.

[0041] To achieve interconnection between the mixing chamber 111 and the ventilation chamber 112, in a preferred embodiment, the horizontal partition 13 can be configured as a porous plate structure with several through holes. Multiple through holes 132 are formed on the plate surface, and multiple nozzles 131 communicating with the through holes 132 and extending downwards are correspondingly arranged on the side of the horizontal partition 13 facing the ventilation chamber 112. In other alternative embodiments, an annular ventilation gap (not shown) can be reserved between the outer edge of the horizontal partition 13 and the inner wall of the sleeve, or the horizontal partition 13 can be made of a porous material such as porous quartz or porous ceramic. With any of the above structures, the growth source can be allowed to pass through the horizontal partition 13 from top to bottom and enter the ventilation chamber 112 below.

[0042] During the epitaxial wafer growth process, firstly, different growth sources (including group III and group V sources and carrier gas) delivered by multiple air inlet channels 51 are introduced into the mixing chamber 111 through their outlets (not shown). Under the obstruction of the horizontal baffle 13, each growth source forms a moderate retention and disturbance within the mixing chamber 111, providing necessary diffusion space and buffer time for growth sources such as gallium chloride and ammonia, allowing them to undergo gas phase convergence and preliminary mixing, thereby avoiding uneven gas phase concentration distribution caused by differences in the initial flow rates of different growth sources. At the same time, the carrier gas can dilute and block gallium chloride and ammonia, inhibiting gas phase parasitic reactions of gallium chloride and ammonia before reaching the growth surface. Subsequently, the preliminarily mixed growth source gas flow enters the nozzle 131 through the through-hole 132. As the growth sources flow through the nozzle 131, their airflow direction is guided by the flow constraint of the nozzle 131 to be a downward airflow with a consistent direction and uniform velocity. The rectified airflow enters the ventilation chamber 112 from the end of the nozzle 131. The ventilation chamber 112 further equalizes and stabilizes the airflow. Finally, the rectified and stabilized mixed growth source enters the mixing reaction zone 12 with a more stable and uniform flow field for further mixing and reaches the growth surface. This ensures that the substantial chemical vapor deposition reaction occurs precisely on the growth surface, avoiding problems such as uneven epitaxial growth rate and surface morphology defects caused by high-speed airflow directly scouring the growth surface.

[0043] In some examples, the parameter Figure 1 and Figure 3 As shown, the inner circumferential surface of the reaction chamber 10 and the outer circumferential surface of the outer sleeve 33 form a cooling annular gap 15; the multi-chamber growth apparatus 100 also includes an air curtain cooling system, which is connected to the cooling annular gap 15 and is used to introduce cooling gas into the cooling annular gap 15 to form a downward flowing cooling air curtain.

[0044] During operation of the multi-chamber growth apparatus 100, the air curtain cooling system is configured to... Figure 3 Cooling gas is continuously introduced into the cooling annular gap 15 in the direction indicated by the middle arrow Q1. The cooling gas flowing downward at high speed forms a continuous cooling air curtain in the cooling annular gap 15.

[0045] The control system is communicatively connected to the air curtain cooling system. The control system is configured to drive the air curtain cooling system (e.g., adjust the flow control valve inside the air curtain cooling system) to adjust the inflow rate of the cooling air curtain in real time based on the real-time temperature feedback signal. Through the above regulation, excess heat from the outer sleeve 33 cavity wall can be efficiently removed to maintain the temperature of the edge area within a set safe range (e.g., 500°C to 900°C), thereby reducing the radial temperature difference between the center area and the edge area. This avoids large thermal stress on the edge of the epitaxial wafer due to excessive radial temperature difference, effectively reducing the risk of warping and cracking of the epitaxial wafer.

[0046] The multi-chamber growth apparatus 100 also includes a temperature sensing component (not shown). Alternatively, the temperature sensing component may be a thermocouple disposed on the wall of the outer sleeve 33, capable of sensing the temperature data of the outer sleeve 33 wall in real time. The control system receives feedback signals from the temperature sensing component and adaptively adjusts the actions of the air curtain cooling system accordingly (e.g., adjusting the opening degree of the flow control valve).

[0047] The cooling air curtain is configured with a slight positive pressure, its pressure value controlled to be slightly higher than the reaction chamber pressure inside the reaction chamber 10, preferably 10 Pa to 20 Pa higher. This cooling air curtain effectively isolates corrosive gases within the reaction chamber from the inner circumferential surface of the reaction chamber 10 and its surrounding external insulation structure 60, preventing the corrosive gases from diffusing outwards. This reduces corrosion damage to the multi-chamber growth apparatus 100 and extends the overall service life of the equipment. Furthermore, the cooling air curtain also prevents external impurities from penetrating into the reaction chamber 10, ensuring the cleanliness of the epitaxial wafer growth environment.

[0048] For example, the pressure of the cooling air curtain is higher than the reaction chamber pressure inside the reaction chamber 10 by an integer, or a non-integer, such as 10 Pa, 11 Pa, 12 Pa, 13 Pa, 14 Pa, 15 Pa, 16 Pa, 17 Pa, 18 Pa, 19 Pa, or 20 Pa, or a range defined by at least two integers or non-integers.

[0049] To prevent chemical interference with the epitaxial wafer growth inside the reaction chamber 10, the cooling gas introduced into the gas curtain cooling system is preferably an inert gas or a pure carrier gas that does not participate in the epitaxial wafer growth. For example, nitrogen, argon, hydrogen, or a mixture thereof can be used as the cooling gas.

[0050] In some examples, a hollow interlayer (not shown) is formed inside the circumferential wall 301 of each sleeve (i.e., the first sleeve 31, the second sleeve 32, and the outer sleeve 33); a heating layer 302 and a heat insulation layer 303 are sequentially embedded radially from the inside to the outside within the hollow interlayer. The multi-chamber growth apparatus 100 also includes a cavity wall structure 14. The cavity wall structure 14 is an annular structure that is respectively attached to the inner circumferential surface of the first sleeve 31, the second sleeve 32, and the outer sleeve 33. It extends axially along each sleeve and is seamlessly attached to the inner circumferential surface of the circumferential wall 301 of the corresponding sleeve. Each independent cavity 11 is formed by the cavity wall structure 14.

[0051] It should be noted that the cavity wall structure 14, each sleeve, and the reaction chamber 10 can all be made of transparent quartz glass, the main component of which is high-purity silicon dioxide. This high-purity quartz material has high light transmittance covering the ultraviolet to infrared bands and excellent thermal shock resistance. Furthermore, this high light transmittance can provide a non-destructive optical observation channel for the monitoring system located outside the reaction chamber 10, to meet the monitoring needs during the epitaxial wafer growth process. Specifically, the top wall area (not shown) of each sleeve is partially not equipped with a heating layer 302 and a heat insulation layer 303, thus forming a light-transmitting window. The in-situ optical pyrometer can detect the thermal radiation intensity of the growth surface through this light-transmitting window and obtain the actual temperature of each growth zone corresponding to the surface in real time. The growth rate monitoring module can be realized using reflective anisotropic spectroscopy or laser reflection technology, that is, by projecting probe light onto the internal growth surface through the light-transmitting window and receiving the reflected signal returned by the growth surface, thereby monitoring the actual growth rate of the epitaxial wafer corresponding to each growth zone in real time with high precision.

[0052] In a preferred embodiment, the heating unit is configured as a heating layer 302 disposed inside the circumferential cylindrical wall 301. The heating layer 302 generates heat, and since the cavity wall structure 14 is adjacent to the heating layer 302, the heat can pass through the cavity wall structure 14 with a very short path and act directly on the interior of the independent chamber 11 in the form of thermal radiation, thereby achieving rapid heating of the growth zone. At the same time, the heat insulation layer 303 located on the outer ring has a thermal resistance effect, which can prevent heat from dissipating radially to the outside of the reaction chamber 10, so that the heat is confined within the independent chamber 11.

[0053] The heating layer 302 uses an iron-chromium-aluminum heating wire as the heating element, and is preferably wrapped with fire-resistant cotton (such as ceramic fiber cotton or aluminum silicate fiber cotton). In other embodiments, the heating element of the heating layer 302 can also be made of high-temperature electric heating materials such as nickel-chromium alloy, tungsten, molybdenum or tantalum; the fire-resistant cotton can also be replaced by other high-temperature resistant fiber felt, porous ceramic insulation or mineral fiber products, as long as it can play a role in supporting the heating element and assisting in insulation and heat equalization.

[0054] The main material of the insulation layer 303 is mullite. Mullite, as a high-quality refractory mineral phase, has an extremely high load softening temperature and extremely low thermal conductivity. The insulation layer 303 can limit the heat radiated radially outward from the heating layer 302, ensuring that heat is preferentially conducted to the independent chamber 11 through the inner cavity wall structure 14. In other alternative embodiments, the insulation layer 303 may also be selected from one or more of the following materials: alumina-based materials (such as high-purity alumina ceramics, fiber felt, or porous bricks), zirconia-based materials (such as partially stabilized zirconia or ceramic fibers), and composite silicate materials (such as aluminum silicate or magnesium silicate fibers).

[0055] In some examples, an external thermal insulation structure 60 is provided outside the reaction chamber 10. The external thermal insulation structure 60 is configured to cover the periphery of the outer shell of the reaction chamber 10. The external thermal insulation structure 60 is used to isolate the internal thermal field of the reaction chamber 10 from the external atmospheric environment, block the conduction of heat from the internal reaction chamber 10 to the external space, and reduce the interference of the external ambient temperature on the internal thermal field of the reaction chamber 10.

[0056] In some examples, the multiple air intake channels 51 include: multiple first air intake channels 51a, multiple second air intake channels 51b, and multiple third air intake channels 51c. The multiple first air intake channels 51a are arranged at uniform intervals around the central axis P of the first sleeve 31 in the circumferential direction, and their outlets extend together and connect to the first independent chamber 11a, for conveying a mixed growth source containing group III source gas, group V source gas, and carrier gas to the first independent chamber 11a; the multiple second air intake channels 51b are arranged at uniform intervals in the circumferential direction, and their outlets extend together and connect to the second independent chamber 11b, for conveying a mixed growth source containing group III source gas, group V source gas, and carrier gas to the second independent chamber 11b; the multiple third air intake channels 51c are arranged at uniform intervals in the circumferential direction, and their outlets extend together and connect to the third independent chamber 11c, for conveying a mixed growth source containing group III source gas, group V source gas, and carrier gas to the third independent chamber 11c.

[0057] As an exemplary operation of the multi-chamber growth apparatus 100 of the present invention, when preparing large-size epitaxial wafers, the multi-chamber growth apparatus 100 divides the radial region into a central region, an intermediate region, and an edge region, with the geometric center of the tray 20 as the origin. The operating states of the corresponding independent chambers 11 are configured as follows: the central region corresponds to the area with a radial distance of 0 mm to 30 mm from the tray 20. The heating system in the first independent chamber 11a operates at a high temperature of 1100°C to 1200°C, and the growth source flow rate of the first air inlet channel 51a matches this temperature field to maintain a high-speed growth state of 160 to 180 μm / h. The intermediate region corresponds to the area with a radial distance of 30 mm to 60 mm from the tray 20. The heating system in the second independent chamber 11b operates at a temperature of 900°C to 1100°C, with a target growth rate of 140 to 160 μm / h. The edge region corresponds to a radial distance of 60 mm to 76 mm from tray 20. The heating system in the third independent chamber 11c operates at 600°C to 1000°C, and the target growth rate corresponding to the third independent chamber 11c is maintained at 130 to 150 μm / h. To prevent a large radial temperature difference (e.g., greater than 400°C) between the central and edge regions, which could cause thermal stress exceeding the fracture strength of the epitaxial wafer, and to avoid disproportionation deposition of reactive gases at low temperatures, the heating system in this edge region works in conjunction with the cooling gas curtain to strictly maintain the operating temperature of the outer sleeve 33 cavity wall within a safe range of 500°C to 900°C.

[0058] Throughout the complete epitaxial wafer growth cycle, the multi-chamber growth apparatus 100 does not maintain a static isothermal condition. Instead, it exhibits three different radially decreasing temperature gradient distributions, depending on the different evolution stages of crystal growth. Specifically, the initial operating state corresponds to the crystal nucleation stage. During this stage, to meet the lower temperature requirements for crystal nucleation, the heating units of each independent chamber 11 operate at lower power output. For example, in the initial operating state, the temperature of the corresponding central region can be controlled at 1000℃, the temperature of the middle region at 980℃, and the temperature of the edge region at 950℃, with the maximum radial temperature difference controlled at 50℃. At this time, the multi-chamber growth apparatus 100 as a whole maintains a relatively small radial temperature gradient to ensure the uniform nucleation and distribution of three-dimensional crystal nuclei.

[0059] The intermediate operating state corresponds to the crystal growth period. As the crystal growth mode changes to two-dimensional planar growth, the heating units of each independent chamber 11 synchronously increase their power outputs to raise the overall growth temperature. Due to the increased natural heat radiation loss from the central region to the edge region, a medium-strength temperature gradient is naturally formed and maintained in the radial direction of the tray 20 of the multi-chamber growth device 100. For example, in the intermediate operating state, the temperature of the corresponding central region can be controlled at 1100 °C, the temperature of the intermediate region at 1040 °C, the temperature of the edge region at 950 °C, and the maximum radial temperature difference at 150 °C, so as to achieve the purpose of high-speed planar growth of the crystal.

[0060] The late operating state corresponds to the thick film period of the crystal. In this stage, the edge effect of crystal growth intensifies. To suppress the lateral growth at the edge, the multi-chamber growth device 100 enters a large temperature gradient and strong edge cooling state. The strong edge cooling state is specifically manifested as the relative reduction of the heating power of the third independent chamber 11c and the increase in the flow rate of the peripheral cooling air curtain to lower the temperature of the edge region. For example, in the late operating state, the temperature of the corresponding central region is maintained at 1100 °C, the temperature of the intermediate region is controlled at 950 °C, the temperature of the edge region is controlled at 700 °C, and the maximum radial temperature difference is controlled at 400 °C.

[0061] During the above operation process, the parameter adjustment of each growth region (i.e., the central region, the intermediate region, and the edge region) of the multi-chamber growth device 100 has the ability of dynamic response. Specifically, during the growth process of the epitaxial wafer, when the monitoring system real-time obtains that the actual growth rate of the epitaxial wafer in a certain growth region deviates from the preset target range, for example, when it is detected that the actual growth rate in the corresponding edge region is insufficient, the control system separately adjusts the heating power of the corresponding heating unit, or separately adjusts the flow rate of the growth source introduced into the corresponding third intake channel 51c by adjusting the corresponding mass flow controller, or can also adjust both synchronously until the actual growth rate in the edge region falls back within the preset target range, thereby solving the problem of out-of-control growth at the edge of the epitaxial wafer in the prior art and improving the overall thickness uniformity and crystal quality consistency of the epitaxial wafer.

[0062] See Figure 8 As shown, based on the specific implementation manner of the multi-chamber growth device 100 disclosed in the foregoing embodiments, the present invention also discloses a multi-chamber epitaxial growth method, which is applied to the multi-chamber growth device 100. The multi-chamber epitaxial growth method includes the following steps: S1. Place a growth substrate on the tray 20 in the reaction chamber 10.

[0063] S2. Convey various growth sources to each independent chamber 11 through the intake spraying system respectively, and heat each independent chamber 11 through the heating system respectively.

[0064] S3. The actual growth rate of the epitaxial wafer on the growth substrate is obtained in real time through the monitoring system.

[0065] S4. The heating power of the heating unit in the corresponding independent chamber 11 and / or the growth source flow rate into the corresponding air intake channel 51 are adjusted by the control system to maintain the actual growth rate of the epitaxial wafer in each growth zone within the preset target range.

[0066] The multi-cavity external epitaxial growth method disclosed in this invention first involves placing a growth substrate (e.g., sapphire, silicon carbide, or silicon wafer) on a tray 20 within a reaction chamber 10. The surface area of ​​the tray 20 corresponding to each independent chamber 11 above it is divided into multiple growth regions, which include a central region, an intermediate region, and an edge region distributed radially from the inside out.

[0067] Secondly, the air intake spray system delivers the growth source to the corresponding independent chamber 11 through multiple independently controlled air intake channels 51.

[0068] For example, a mixed growth source containing group III source gas, group V source gas and carrier gas is delivered to the first independent chamber 11a through multiple first air inlet channels 51; a mixed growth source containing group III source gas, group V source gas and carrier gas is delivered to the second independent chamber 11b through multiple second air inlet channels 51b; and a mixed growth source containing group III source gas, group V source gas and carrier gas is delivered to the third independent chamber 11c through multiple third air inlet channels 51c. At the same time, the carrier gas can dilute and block gallium chloride and ammonia, suppressing the gas-phase parasitic reaction of gallium chloride and ammonia before they reach the growth surface.

[0069] For example, at least one first intake channel 51 supplies group III source reactant gas to the first independent chamber 11a, at least one second intake channel 51b supplies group V source gas to the second independent chamber 11b, and at least one third intake channel 51c supplies carrier gas to the third independent chamber 11c. The physical barrier formed by multiple coaxially arranged sleeves (such as the first sleeve 31, the second sleeve 32, and the outer sleeve 33) in the reaction chamber 10 can block the lateral diffusion of the growth source, so that the growth source is radially physically isolated in each independent chamber 11, and avoids premature mixing of group III source reactant gas and group V source gas to prevent gas-phase parasitic reaction.

[0070] The heating system comprises multiple independently controlled heating units (such as heating layers 302 embedded in the hollow interlayers within the circumferential walls 301 of each sleeve). The heating power of each heating unit can be independently adjusted, and each heating unit can independently and precisely heat its corresponding independent chamber 11. Under the action of the corresponding heating unit, each independent chamber 11 forms an independent zoned temperature field, which further acts on the corresponding growth zones on the tray 20 through thermal radiation and thermal conduction. Since the heating power of each heating unit can be independently adjusted and does not interfere with each other, the radial temperature zones of each growth zone on the tray 20 can be independently controlled.

[0071] Subsequently, during the growth of the epitaxial wafer, the monitoring system detects the thermal radiation intensity of the growth surface through a temperature monitoring module (such as an in-situ optical pyrometer) to obtain the actual temperature of each growth zone, and projects probe light onto the growth surface and receives the reflected signal through a growth rate monitoring module (such as based on reflective anisotropic spectrum or laser reflection technology), thereby realizing real-time monitoring to obtain the actual growth rate of the epitaxial wafer corresponding to each growth zone.

[0072] Finally, the control system receives real-time feedback from the monitoring system on the actual temperature and actual growth rate of each growth zone and compares them with the preset target range. If the actual growth rate of any growth zone (e.g., the edge zone) deviates from the preset target range, the control system initiates regulation, adjusting the heating power of the heating unit corresponding to that growth zone individually, or adjusting the growth source flow rate of the air intake channel 51 corresponding to that growth zone, or adjusting both simultaneously, until the growth rate of that growth zone falls back into the preset target range.

[0073] During the epitaxial wafer growth process, the multi-chamber growth apparatus 100 adaptively adjusts the preset temperature target range and preset growth rate target range for each growth region according to different growth stages: the crystal nucleation stage, the crystal growth stage, and the crystal thick film stage. Based on the different evolution stages of crystal growth, different radially decreasing temperature gradient distributions are observed. Details regarding the specific temperature parameters, temperature gradient distribution, and growth rate control for each growth stage have been described in detail in the aforementioned embodiments of the multi-chamber growth apparatus 100 and will not be repeated here. Simultaneously, the separation of each independent chamber 11 avoids heat crosstalk and mutual interference between different growth regions, thereby suppressing parasitic growth and controlling the thermal stress of the epitaxial wafer. This solves the technical problems of uncontrolled edge growth and warping cracking in large-size epitaxial wafers in the prior art, improving the overall thickness uniformity and crystal quality consistency of the epitaxial wafer.

[0074] In some examples, the actual growth rate of the epitaxial wafer on the growth substrate is obtained in real time, including: S31. The control system acquires the actual temperature of each growth zone and the partial pressure of the growth source; wherein, the partial pressure of the growth source is the ratio of the pressure of one of the multiple growth sources to the total pressure of all growth sources entering the reaction chamber.

[0075] The partial pressure of the growth source corresponds to the pressure ratio of the growth source that plays a dominant role in the crystal growth rate among various growth sources. Because it plays a decisive role in the source transport control of thin film growth, it is preferably the pressure ratio of group III source reactive gas (such as gallium chloride). Its magnitude is related to the ratio of the flow rate of group III source reactive gas delivered by the corresponding gas inlet channel 51 to the total flow rate of all growth sources in the reaction chamber 10. It can be calculated in real time by the control system in combination with the real-time flow data of the mass flow controller, based on the proportional conversion relationship in the gas partial pressure law. The relevant calculation logic is common knowledge in the field and is not an improvement of this invention, so the specific formula will not be described in detail. Alternatively, in order to further ensure the accuracy of the partial pressure of the growth source, the multi-chamber growth device 100 can also add a partial pressure monitoring component (not shown) in each independent chamber 11. The partial pressure monitoring component is communicatively connected to the control system and can directly collect the partial pressure data of the growth source in each independent chamber 11 in real time.

[0076] S32. The control system calculates the actual growth rate of the growth zone based on the actual temperature of the growth zone and the partial pressure of the growth source; wherein, the actual growth rate increases with the increase of the actual temperature and the partial pressure of the growth source.

[0077] During the epitaxial growth process, the actual temperature of each growth region is detected in real time by the temperature monitoring module and fed back to the control system. Based on the preset epitaxial growth kinetic formula, the control system uses the actual temperature of each growth region and the partial pressure of the growth source as input parameters to calculate the actual growth rate of the epitaxial wafer corresponding to each growth region.

[0078] Any radial position of tray 20 The actual growth rate of the epitaxial wafer corresponding to any given location (i.e., any growth region) can be calculated using the following epitaxial growth kinetics formula: ; Among them, parameters This represents the pre-factor, in units of m / (s·Pa), and the parameter... The activation energy of the epitaxial growth reaction is expressed in J / mol. (Parameter) The three parameters represent the ideal gas constant, expressed in J / (mol·K). These three parameters are calibration constants related to the epitaxial material system and the epitaxial process environment, and can be pre-stored in the control system after calibration through previous epitaxial process experiments. Indicates tray 20 radial The actual growth rate at that location, in m / s; parameters Indicates tray 20 radial The actual temperature of the growth surface at the point, in K; parameters Indicates tray 20 radial The corresponding partial pressure of gallium chloride gas at that location is expressed in Pa.

[0079] Based on the above epitaxial growth kinetics formula, the actual growth rate shows a clear positive correlation with the partial pressure of the growth source and the actual temperature. (Tray 20 radial) The corresponding actual growth rate and There is a linear positive correlation; under constant temperature conditions, the higher the partial pressure of the growth source, the more reaction particles participate in the vapor deposition reaction per unit time, and the faster the crystal growth rate. Tray 20 radial The corresponding actual growth rate Compared with actual temperature The growth rate exhibits an exponential positive correlation. Under the condition of constant partial pressure of the growth source, the higher the actual temperature, the stronger the activity of the reacting particles, and the faster the vapor deposition reaction rate, thereby driving an exponential increase in the epitaxial wafer growth rate. This verifies that the present invention achieves precise control of the growth rate by independently adjusting the temperature and growth source flow rate of each growth zone.

[0080] In some examples, the growth zone includes a central zone, an intermediate zone, and an edge zone distributed from the inside out. The edge zone corresponds to the outermost radial region of the tray 20 and is directly opposite the third independent chamber 11c. Due to the edge effect of the epitaxial process, the growth rate in this edge zone is prone to deviating from the preset target range. To address this, this embodiment provides two adaptively switchable closed-loop control methods for the edge zone (both based on the built-in discrimination module of the control system combined with a conventional PID control algorithm, which is a conventional technology in the field of industrial process control, so the specific mathematical model is not described in detail).

[0081] When the control system detects that the actual growth rate of the edge region does not fall within the preset target range, it adjusts the heating power corresponding to the edge region and detects the adjusted actual growth rate. Based on the adjusted actual growth rate and the actual growth rate before adjustment, it calculates the growth rate change rate (hereinafter referred to as "growth rate response change rate"). If the growth rate change rate is greater than the set value, it continues to adjust the heating power corresponding to the edge region until the actual growth rate of the edge region falls within the preset target range. If the growth rate change rate is less than or equal to the set value, it adjusts the growth source flow rate corresponding to the edge region until the actual growth rate of the edge region falls within the preset target range. The above is the first control method, which prioritizes adjusting the heating power corresponding to the edge region. When the control system detects that the actual growth rate of the edge region does not fall within the preset target range, it executes the following steps: S321, The control system outputs adjustment commands and outputs power adjustment signals through the PID control algorithm, prioritizing the adjustment of the heating power of the heating unit in the third independent chamber 11c corresponding to the edge area.

[0082] S322. After the heating power adjustment action of the heating unit is completed, the actual growth rate of the edge area after adjustment is detected and obtained in real time by the monitoring system, and synchronously fed back to the discrimination module built into the control system.

[0083] S323. The control system uses a discrimination module to compare and analyze the actual growth rate after adjustment with the actual growth rate before adjustment, so as to obtain the growth rate response change rate of this regulation (i.e., the ratio between the change in the actual growth rate of the edge region caused by the control system performing power adjustment on the heating unit of the third independent chamber 11c and the change in the output of heating power).

[0084] S324. If the determined growth rate response change rate is greater than the preset set value (the set value is the sensitivity threshold calibrated in the previous epitaxial process test, which is preset and stored in the control system), it indicates that the current growth rate of the edge region is sensitive to the temperature regulation of the edge region and the effect is significant. Then the control system continues to adjust the heating power corresponding to the edge region individually through the PID control algorithm and perform iterative correction until the actual growth rate of the edge region falls back into the preset target range.

[0085] S325. If the determined growth rate response change rate is less than or equal to the set value, it indicates that the current growth rate of the edge zone responds slowly to the temperature regulation of the edge zone, and it is difficult to quickly correct the growth rate deviation by adjusting the heating power alone. At this time, the discrimination module of the control system automatically switches the control object and adjusts the growth source flow of the third air intake channel 51c corresponding to the edge zone through the PID algorithm until the actual growth rate of the edge zone falls back into the preset target range.

[0086] When the control system detects that the actual growth rate of the edge region does not fall within the preset target range, it adjusts the flow rate of the growth source corresponding to the edge region and detects the adjusted actual growth rate. Based on the adjusted actual growth rate and the actual growth rate before adjustment, it calculates the growth rate change rate. If the growth rate change rate is greater than the set value, it continues to adjust the flow rate of the growth source corresponding to the edge region until the actual growth rate of the edge region falls within the preset target range. If the growth rate change rate is less than or equal to the set value, it adjusts the heating power corresponding to the edge region until the actual growth rate of the edge region falls within the preset target range. The above is the second control method, which prioritizes adjusting the flow rate of the growth source corresponding to the edge region. When the control system detects that the actual growth rate of the edge region does not fall within the preset target range, it executes the following steps: S321' The control system outputs adjustment commands and outputs flow adjustment signals through the PID control algorithm, prioritizing the adjustment of the growth source flow rate corresponding to the third air intake channel 51c in the edge area (achieved by adjusting the corresponding mass flow controller to precisely control the supply of growth source).

[0087] After the growth source flow adjustment action is completed (S322'), the monitoring system detects and obtains the actual growth rate of the edge region after adjustment in real time, and synchronously feeds it back to the discrimination module built into the control system.

[0088] S323' The control system compares and analyzes the actual growth rate after adjustment with the actual growth rate before adjustment through the discrimination module, so as to obtain the growth rate response change rate of this regulation (that is, the ratio between the change in the actual growth rate of the edge region caused by the control system performing flow regulation on the mass flow controller of the third air intake channel 51c and the change in the output flow of the growth source).

[0089] S324' If the determined growth rate response change rate is greater than the preset set value, it indicates that the current growth rate of the edge region is sensitive to the regulation of the reaction source flow and the effect is significant; then the control system continues to adjust the growth source flow corresponding to the edge region individually through the PID control algorithm and perform iterative correction until the actual growth rate of the edge region falls back into the preset target range.

[0090] S325' If the determined growth rate response change rate is less than or equal to the set value, it indicates that the current growth rate of the edge zone responds slowly to the regulation of the growth source flow rate, and it is difficult to quickly correct the growth rate deviation by adjusting the flow rate alone. At this time, the discrimination module of the control system automatically switches the control object and adjusts the heating power of the corresponding heating unit in the edge zone through the PID algorithm until the actual growth rate of the edge zone falls back into the preset target range.

[0091] In summary, the two control methods described above combine the control capabilities of conventional PID control algorithms with automatic switching logic, solving the technical defects of existing single control methods (adjusting only temperature or only growth source flow) such as slow control response, over-adjustment, or control failure. They can accurately correct deviations in the growth rate of the edge region, thereby improving the growth uniformity of the edge region of large-size epitaxial wafers and further ensuring the overall thickness uniformity and crystal quality consistency of the epitaxial wafers.

[0092] In some examples, the multi-cavity epitaxial growth method further includes: before the epitaxial wafer begins growth, the control system pre-determines the initial heating power of each heating unit and the initial growth source flow rate of each air inlet channel 51. This provides a suitable initial process baseline for the subsequent stable growth of the epitaxial wafer, avoiding problems such as growth rate fluctuations and uneven crystal nucleation caused by parameter imbalances in the early stages of growth. The specific implementation process is as follows: (1) The control system acquires the target growth rate corresponding to each growth region. Among them, each growth region is divided into a central region, an intermediate region, and an edge region from the inside to the outside along the radial direction of the tray 20, which correspond to the first independent chamber 11a, the second independent chamber 11b, and the third independent chamber 11c, respectively. The target growth rate of each growth region is a process target value that is pre-calibrated and stored in the control system according to the specific epitaxial growth process (such as gallium nitride) requirements (for example, the target growth rate of the central region is 160 to 180 μm / h, the target growth rate of the intermediate region is 140 to 160 μm / h, and the target growth rate of the edge region is 130 to 150 μm / h). The control system directly calls the preset process target value to complete the acquisition of the target growth rate parameters corresponding to each growth region.

[0093] (2) The control system determines the initial target temperature and / or initial target growth source partial pressure corresponding to each growth zone based on each target growth rate and the preset process setting parameters; wherein the preset process setting parameters include preset process temperature or preset growth source partial pressure.

[0094] The control system matches the target growth rate with the preset process setting parameters through a preset process recipe table (referring to the correspondence between the initial target temperature, initial target growth source partial pressure, and other process parameters for each growth zone under different target growth rates, stored in the control system) and feedforward parameter mapping logic (this logic is a conventional setting method in this field, and its implementation details are not elaborated). This determines the initial target temperature and / or initial target growth source partial pressure that is suitable for the target growth rate. The mapping derivation logic is as follows: if the preset process setting parameter is a preset process temperature, the control system uses it as the initial target temperature and derives the required initial target growth source partial pressure by combining it with the target growth rate mapping; if the setting parameter is a preset growth source partial pressure, the control system uses it as the initial target growth source partial pressure and derives the required initial target temperature by combining it with the target growth rate mapping.

[0095] (3) The control system determines the initial heating power of each heating unit and / or the initial growth source flow rate into each air intake channel 51 based on the initial target temperature and / or the initial target growth source partial pressure of each growth zone.

[0096] The central region corresponds to the first independent chamber 11a. Based on the initial target temperature of the central region, the control system determines the initial heating power of the corresponding heating unit; the control system also determines the initial growth source flow rate into the first air intake channel 51a based on the initial target growth source pressure of the central region. The middle region corresponds to the second independent chamber 11b. Based on the initial target temperature of the middle region, the control system determines the initial heating power of the corresponding heating unit; the control system also determines the initial growth source flow rate into the second air intake channel 51b based on the initial target growth source pressure of the middle region. The edge region corresponds to the third independent chamber 11c. Based on the initial target temperature of the edge region, the control system determines the initial heating power of the corresponding heating unit; the control system also determines the initial growth source flow rate into the third air intake channel 51c based on the initial target growth source pressure of the edge region.

[0097] In some examples, the multi-cavity external epitaxial growth method also includes: (1) When adjusting the heating power of the heating unit of the corresponding independent chamber 11, the control system calculates the maximum radial temperature difference of the tray 20 in real time based on the actual temperature of each growth zone.

[0098] The actual temperature includes the actual temperature of the central zone, the actual temperature of the middle zone, and the actual temperature of the edge zone. Based on the actual temperature of each growth zone, the control system calculates the maximum radial temperature difference of the tray in real time. The maximum temperature difference The difference between the highest and lowest radial temperatures of tray 20, especially the difference between the actual temperature in the central area and the actual temperature in the edge area, determines the level of thermal stress inside the epitaxial wafer.

[0099] (2) The control system calculates the thermal stress generated by the epitaxial wafer in real time based on the maximum temperature difference.

[0100] The control system is based on the maximum temperature difference. Combined with a pre-set thermal stress calculation model, the thermal stress generated by the current epitaxial wafer is calculated in real time. Specifically, the control system performs real-time calculations based on the following thermal stress theoretical model: ; Among them, parameters The thermal stress of the epitaxial wafer is expressed in Pa; parameters This represents the Young's modulus of an epitaxial wafer material (e.g., gallium nitride), expressed in Pa; Parameter This represents the coefficient of thermal expansion of the epitaxial wafer material, expressed in units of 1 / K; Parameter This represents the Poisson's ratio of the epitaxial wafer material, and is a dimensionless parameter; parameter This represents the maximum radial temperature difference calculated in real time, in Kelvin (K).

[0101] The control system continuously applies the thermal stress calculated in real time. The stress threshold is compared with a preset stress threshold. The preset stress threshold is a critical value calibrated based on the fracture strength of the epitaxial material (e.g., the fracture strength of gallium nitride is about 1 GPa) and after reserving a safety margin.

[0102] (3) When the control system determines that the thermal stress reaches the preset stress threshold, it calculates the maximum safe temperature difference based on the preset stress threshold and limits the single adjustment range of the heating power of the corresponding heating unit to a power range that ensures the maximum radial temperature difference does not exceed the maximum safe temperature difference.

[0103] When the control system determines that the current thermal stress has reached a preset stress threshold, it first uses the aforementioned thermodynamic model to deduce the maximum safe temperature difference that the epitaxial wafer material can withstand, based on the preset stress threshold. The maximum safe temperature difference is the maximum allowable temperature range in the radial direction of tray 20, provided that the thermal stress does not exceed the fracture strength. Specifically, the stress threshold is substituted into the thermal stress quantification formula for inverse calculation (this inverse calculation is a conventional numerical calculation method in this field, so the specific calculation process will not be described in detail here), directly determining the maximum safe temperature difference that matches the stress threshold. Subsequently, to ensure the safety of the epitaxial wafer structure, the control system limits the single adjustment range of the heating power of the heating unit corresponding to the independent chamber 11 to within a safe range. Specifically, when adjusting the heating unit power, the control system must ensure that the maximum radial temperature difference of tray 20 after adjustment does not exceed the maximum safe temperature difference. This avoids the accumulation of thermal stress caused by excessive radial temperature difference of the epitaxial wafer (such as exceeding 400°C), keeps the thermal stress of the epitaxial wafer below the fracture strength, and avoids the risk of wafer cracking.

[0104] In some examples, the multiple sleeves include an outermost outer sleeve 33; the inner circumferential surface of the reaction chamber 10 and the outer circumferential surface of the outer sleeve 33 enclose a cooling annular gap 15; the multi-chamber growth apparatus 100 also includes an air curtain cooling system, which is connected to the cooling annular gap 15 and is used to introduce cooling gas into the cooling annular gap 15 to form a downward-flowing cooling air curtain; during the growth of the epitaxial wafer, the control system adjusts the flow rate of the cooling gas based on the current heating power of each heating unit so that the cavity wall temperature of the outer sleeve 33 is maintained within a preset temperature range.

[0105] Based on the conventional convective heat transfer principle in this field, the convective heat transfer coefficient of the cooling air curtain... Related to the flow rate of the cooling gas and the thermal conductivity of the cooling gas The relationship is related and can be characterized by the convective heat transfer formula: ; Among them, parameters The convective heat transfer coefficient of the cooling air curtain is expressed in W / (m²·K); parameters The parameter represents the Nusselt number, is dimensionless, and is positively correlated with the flow rate of the cooling gas; The thermal conductivity of the cooling gas is expressed in W / (m·K); parameter The characteristic length, expressed in meters, corresponds to the structure of the cooling annular gap 15. In the context of this invention, the cooling air curtain flows downwards along the axial direction of the cooling annular gap 15. Preferably, the axial effective heat transfer height of the cooling annular gap 15 (i.e., the effective axial heat transfer length of the outer sleeve 33) is the characteristic length. The specific values ​​and their corresponding Nusselt numbers are conventional and well-known techniques for heat exchange calculations in this field, so the specific values ​​and calculation details will not be elaborated here.

[0106] Therefore, the higher the flow rate of the cooling gas, the higher the Nusselt number. The larger the coefficient, the greater the convective heat transfer coefficient. The higher the velocity, the stronger the cooling effect of the cooling air curtain on the outer sleeve 33 cavity wall, and the faster it can remove excess heat from the outer sleeve 33 cavity wall; conversely, the lower the flow rate of the cooling gas, the weaker the cooling effect.

[0107] During the growth of the epitaxial wafer, the control system acquires the heating power of each heating unit (corresponding to the heating units in the central area, middle area, and edge area) in real time, and acquires the actual temperature of the outer sleeve 33 cavity wall in real time through the temperature monitoring module.

[0108] When the heating power of the heating unit in the edge area is detected to be too high, causing the temperature of the outer sleeve 33 cavity wall to exceed the upper limit of the preset temperature range (e.g., 500°C to 900°C), the flow rate of the cooling gas is automatically increased to improve the convective heat transfer coefficient and quickly remove excess heat from the outer sleeve 33 cavity wall, causing the temperature of the outer sleeve 33 cavity wall to drop back to the preset temperature range. When the heating power of the heating unit in the edge area is detected to be insufficient, causing the temperature of the outer sleeve 33 cavity wall to drop below the lower limit of the preset temperature range, the flow rate of the cooling gas is automatically reduced to weaken the cooling effect, causing the temperature of the outer sleeve 33 cavity wall to rise back to the preset temperature range.

[0109] Through continuous iterative adjustments, the temperature of the outer sleeve 33 cavity wall is stably maintained within a preset temperature range. This preset temperature range is a process safety boundary calibrated through process testing. The setting of this process safety boundary must simultaneously meet the following requirements: its lower limit must ensure that the minimum temperature of the outer sleeve 33 cavity wall is always above 500℃ to prevent the disproportionation reaction of group III source reactive gases (such as gallium chloride) in the edge region, thus generating polycrystalline solid gallium and suppressing parasitic growth on the outer sleeve 33 cavity wall; and the adjustment of the outer sleeve 33 cavity wall temperature must be coordinated with the power output of the heating unit in the corresponding independent chamber 11 to ensure that the maximum radial temperature difference of the tray 20 is always maintained within the maximum safe temperature difference allowed by the fracture strength of the epitaxial wafer material, thereby preventing excessive thermal stress that could lead to warping or cracking of the epitaxial wafer.

[0110] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

[0111] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A multi-chamber growth apparatus, characterized in that, include: The reaction chamber is provided with a tray for supporting the growth substrate and multiple sleeves. The multiple sleeves divide the reaction chamber radially to form multiple independent chambers. The surface area of ​​the tray corresponding to each of the independent chambers is divided into multiple growth zones. A heating system comprising multiple independently controlled heating units, with each independent chamber corresponding to at least one heating unit; An air intake spray system includes multiple independently controlled air intake channels, and each independent chamber is provided with at least one air intake channel. The air intake channel is used to deliver multiple growth sources downward to the corresponding independent chamber. The monitoring system is used to acquire the actual temperature of each growth zone and the actual growth rate of the epitaxial wafer on the growth substrate in real time. The control system is communicatively connected to the heating system, the air intake spray system, and the monitoring system. The control system is configured to adjust the heating power of the corresponding heating unit and / or the flow rate of the growth source introduced into the air intake channel based on the actual temperature and the actual growth rate, so as to maintain the growth rate of the epitaxial wafers corresponding to each growth zone within a preset target range.

2. The multi-chamber growth apparatus according to claim 1, characterized in that, The plurality of sleeves includes a first sleeve, a second sleeve, and an outer sleeve arranged radially from the inside to the outside; The axial length of the first sleeve is less than the axial length of the second sleeve, and the axial length of the second sleeve is less than the axial length of the outer sleeve.

3. The multi-chamber growth apparatus according to claim 1, characterized in that, Each of the independent chambers is provided with a horizontal partition, which is used to divide the independent chambers into a mixing chamber and a ventilation chamber that are interconnected along the axial direction. A mixing reaction zone connecting each of the independent chambers is formed above the tray; The mixing chamber is used to mix the multiple growth sources. The ventilation chamber is connected to the mixing reaction zone. The outlet of the air inlet channel is located in the mixing chamber. After the multiple growth sources are mixed in the mixing chamber, they are transported to the mixing reaction zone through the ventilation chamber.

4. The multi-chamber growth apparatus according to claim 2, characterized in that, The inner circumferential surface of the reaction chamber and the outer circumferential surface of the outer sleeve form a cooling annular gap; The multi-chamber growth apparatus also includes an air curtain cooling system, which is connected to the cooling annulus and is used to introduce cooling gas into the cooling annulus to form a downward-flowing cooling air curtain.

5. A multi-cavity external epitaxial growth method, characterized in that, Applied to the multi-chamber growth apparatus as described in any one of claims 1 to 4, the method comprises the following steps: A growth substrate is placed on a tray within the reaction chamber; The air intake spray system delivers multiple growth sources downwards to each of the independent chambers, and the heating system heats each of the independent chambers. The actual growth rate of the epitaxial wafer on the growth substrate is obtained in real time through the monitoring system. The heating power of the heating unit corresponding to the independent chamber and / or the flow rate of the growth source introduced into the corresponding air intake channel are adjusted by the control system to maintain the actual growth rate of the epitaxial wafer corresponding to each growth zone within a preset target range.

6. The multi-cavity external epitaxial growth method according to claim 5, characterized in that, The real-time acquisition of the actual growth rate of the epitaxial wafer on the growth substrate includes: The control system acquires the actual temperature of each growth zone and the partial pressure of the growth source; wherein, the partial pressure of the growth source is the ratio of the pressure of one of the multiple growth sources to the total pressure of all growth sources entering the reaction chamber; The control system calculates the actual growth rate of the growth zone based on the actual temperature of the growth zone and the partial pressure of the growth source. The actual growth rate increases with the increase of the actual temperature and the partial pressure of the growth source.

7. The multi-cavity external epitaxial growth method according to claim 5, characterized in that, The growth region includes a central region, an intermediate region, and an edge region distributed from the inside out; the method further includes: When the control system detects that the actual growth rate of the edge region does not fall within the preset target range, it adjusts the heating power corresponding to the edge region and detects the adjusted actual growth rate. Based on the adjusted actual growth rate and the actual growth rate before adjustment, it calculates the growth rate change rate. If the growth rate change rate is greater than a set value, it continues to adjust the heating power corresponding to the edge region until the actual growth rate of the edge region falls within the preset target range. If the growth rate change rate is less than or equal to the set value, it adjusts the growth source flow rate corresponding to the edge region until the actual growth rate of the edge region falls within the preset target range. Alternatively, when the control system detects that the actual growth rate of the edge region does not fall within the preset target range, it adjusts the growth source flow rate corresponding to the edge region and detects the adjusted actual growth rate; based on the adjusted actual growth rate and the actual growth rate before adjustment, it calculates the growth rate change rate; if the growth rate change rate is greater than a set value, it continues to adjust the growth source flow rate corresponding to the edge region until the actual growth rate of the edge region falls within the preset target range; if the growth rate change rate is less than or equal to the set value, it adjusts the heating power corresponding to the edge region until the actual growth rate of the edge region falls within the preset target range.

8. The multi-cavity external epitaxial growth method according to claim 6, characterized in that, The method further includes: Before the epitaxial wafer begins growth, the control system pre-determines the initial heating power of each heating unit and the initial growth source flow rate of each air intake channel, specifically including: The control system acquires the target growth rate corresponding to each growth zone; The control system determines the initial target temperature and / or the initial target growth source partial pressure corresponding to each growth zone based on each target growth rate and preset process setting parameters; wherein, the preset process setting parameters include preset process temperature or preset growth source partial pressure; The control system determines the initial heating power of each heating unit and / or the initial growth source flow rate into each air intake channel based on the initial target temperature and / or the initial target growth source partial pressure corresponding to each growth zone.

9. The multi-cavity external epitaxial growth method according to claim 6, characterized in that, The method further includes: When adjusting the heating power of the heating unit corresponding to the independent chamber, the control system calculates the maximum radial temperature difference of the tray in real time based on the actual temperature of each growth zone; The control system calculates the thermal stress generated by the epitaxial wafer in real time based on the maximum temperature difference. When the control system determines that the thermal stress has reached a preset stress threshold, it calculates the maximum safe temperature difference based on the preset stress threshold and limits the single adjustment range of the heating power of the corresponding heating unit to a power range that ensures the maximum radial temperature difference does not exceed the maximum safe temperature difference.

10. The multi-cavity external epitaxial growth method according to claim 6, characterized in that, The plurality of sleeves includes an outermost outer sleeve; the inner circumferential surface of the reaction chamber and the outer circumferential surface of the outer sleeve form a cooling annular gap; The multi-chamber growth apparatus also includes an air curtain cooling system, which is connected to the cooling annulus and is used to introduce cooling gas into the cooling annulus to form a downward-flowing cooling air curtain. During the growth of the epitaxial wafer, the control system adjusts the flow rate of the cooling gas based on the current heating power of each heating unit, so that the cavity wall temperature of the outer sleeve is maintained within a preset temperature range.

Images