Indium phosphide single crystal growth furnace

Abstract

The present application relates to the technical field of semiconductor crystal growth equipment, and discloses an indium phosphide single crystal growth furnace, which comprises a furnace body, a furnace cover, a main heater, a protective sleeve, a crucible, a lifting and rotating mechanism, a pulling mechanism, a radiation homogenization cover, a shielding adjustment cover and a slow-release discharge pipe. The radiation homogenization cover is arranged on the opening of the protective sleeve, the shielding adjustment cover is arranged on the lower side of the radiation homogenization cover and forms an annular radiation compensation gap, and the shielding adjustment cover moves up and down to adjust the compensation radiation heat. The inner cavity of the radiation homogenization cover, the shielding adjustment cover and the upper space between the crucible opening and the melt liquid surface form a limited gas phase heat buffer zone, which is used for making phosphorus vapor, protective gas and / or volatile matter stay, diffuse, exchange heat and slowly release. The structure can stabilize the thermal boundary of the upper space of the crucible opening and reduce phosphorus vapor pollution.

Description

Technical Field

[0001] This invention relates to the field of semiconductor crystal growth equipment technology, and in particular to an indium phosphide single crystal growth furnace. Background Technology

[0002] Indium phosphide single crystals can be grown using the liquid-sealed Czochralski method. This type of single crystal growth furnace generally includes a furnace body, a main heater, a crucible, a crucible lifting and rotating mechanism, a seed crystal pulling mechanism, and an atmosphere control structure. During growth, the surface of the indium phosphide melt inside the crucible is usually covered with a liquid-sealing material to suppress phosphorus volatilization. The main heater is primarily used to establish segmented temperature fields in the crucible and melt region, while the crucible lifting and rotating mechanism is used to adjust the position of the crucible relative to the main thermal field within the furnace.

[0003] During the liquid-sealed Czochralski process, as the crystal is continuously pulled, the melt inside the crucible is gradually consumed, and the melt level tends to decrease relative to the crucible opening. Even if the position of the melt level relative to the main thermal field inside the furnace is maintained within a preset range by the crucible lifting mechanism, the upper internal space between the crucible opening and the melt level will still gradually increase. After this upper space increases, the flow path, residence time, and heat transfer state of the protective gas, phosphorus vapor, and volatiles of the liquid-sealing material near the crucible opening are prone to change.

[0004] Existing single-crystal furnaces mostly focus on overall thermal field control, crucible body temperature gradient adjustment, or crystal pulling zone airflow control, making it difficult to form a stable local gas phase thermal boundary for the gradually increasing upper space between the crucible opening and the melt surface. If the crucible opening is directly open to the furnace space, phosphorus vapor, protective gas, and volatiles escaping from the crucible opening are prone to disordered convection and rapid escape, causing sudden heat loss and local temperature field fluctuations at the crucible opening.

[0005] Furthermore, phosphorus vapors and volatiles from liquid sealing materials, after diffused disorderly within the furnace, can easily deposit and contaminate the surfaces of components such as the main heater, protective sleeve, furnace cover, observation window, or insulation structure, affecting the cleanliness and thermal repeatability of the furnace. If the volatile gases are directly discharged through ordinary exhaust pipes, it may disrupt the gas-phase thermal balance in the space above the crucible opening, causing local thermal boundary disturbances.

[0006] Therefore, it is necessary to provide a new structure for an indium phosphide single crystal growth furnace that can form a confined gas phase thermal buffer zone between the crucible opening and the melt surface, and adjust the compensating heat input in this region through an adjustable radiation compensation structure, while slowly releasing phosphorus vapor and volatiles along a preset path to improve the stability of the temperature field in the space above the crucible opening and reduce furnace contamination. Summary of the Invention

[0007] The purpose of this invention is to provide an indium phosphide single crystal growth furnace to solve the problems of disordered gas flow at the crucible opening, rapid escape of phosphorus vapor and volatiles, local thermal boundary fluctuations, and furnace contamination during the liquid-sealed Czochralski process, as the melt level descends relative to the crucible opening.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: an indium phosphide single crystal growth furnace, comprising: The furnace body includes a main heater, a protective sleeve, and a crucible. The protective sleeve surrounds the outside of the main heater and forms a high-temperature cavity inside the protective sleeve. An atmosphere cavity is formed between the protective sleeve and the inner wall of the furnace body. The crucible is placed inside the high-temperature cavity, and a lifting and rotating mechanism supporting the crucible is provided at the bottom of the furnace body. A furnace cover is disposed above the furnace body. The furnace cover is provided with a lifting mechanism for driving the seed crystal rod to rise and fall. A radiation homogenization hood and a shielding adjustment hood are provided on the lower side of the furnace cover. A driving assembly and a slow-release discharge pipe are provided on the upper side of the furnace cover. The driving assembly is used to drive the shielding adjustment hood to move up and down along the crucible axis. The slow-release discharge pipe is directly or indirectly connected to the inner cavity of the radiation homogenization hood, and a flow rate adjustment assembly is provided on the slow-release discharge pipe. The radiation homogenizing hood has an inner cavity facing the crucible opening, the radiation homogenizing hood is installed over the upper opening of the protective sleeve, the shielding adjustment hood is installed below the radiation homogenizing hood, and an annular radiation compensation gap is formed between the shielding adjustment hood and the radiation homogenizing hood. The annular radiation compensation gap is used to allow the main heater to input compensating radiation heat into the inner cavity of the radiation homogenization cover, and the shielding adjustment cover moves up and down to adjust the opening of the annular radiation compensation gap. The inner cavity of the radiation homogenization hood and the shielding adjustment hood together enclose the area above the crucible opening and communicate with the upper space between the crucible opening and the melt surface to form a confined gas phase thermal buffer zone. The confined gas phase thermal buffer is used to retain and diffuse the phosphorus vapor, protective gas and / or volatiles escaping from the crucible opening before discharge, and exchange heat with the inner wall of the radiation homogenization shroud and / or the shielding adjustment shroud. The gas phase heat exchange state in the confined gas phase thermal buffer changes with the opening of the annular radiation compensation gap, so as to homogenize the compensation radiation heat and the heat carried by the gas phase medium escaping from the crucible opening in the upper space between the crucible opening and the melt surface.

[0009] Preferably, the radiation homogenizing cover is a conical cover structure with a smaller top and a larger bottom, and the inner wall of the radiation homogenizing cover forms a conical radiation homogenizing surface; the conical radiation homogenizing surface is used to receive the compensating radiation heat entering through the annular radiation compensation gap, and to guide the compensating radiation heat to the upper space between the crucible opening and the melt surface by means of reflection, diffuse reflection and / or re-radiation.

[0010] Preferably, the surface of the radiation homogenization hood is provided with a plurality of air guide holes, the radiation homogenization hood is fixedly installed on the lower surface of the furnace cover, and a buffer cavity is formed between the radiation homogenization hood and the furnace cover; the slow-release emission pipe communicates with the inner cavity of the radiation homogenization hood through the buffer cavity and the air guide holes, so that the phosphorus vapor, protective gas and / or volatiles in the confined gas phase thermal buffer zone enter the buffer cavity through the air guide holes and are then discharged through the slow-release emission pipe.

[0011] Preferably, the plurality of air guide holes are distributed circumferentially along the radiation homogenization shield, and the air guide holes constitute throttling orifices to limit the instantaneous flow rate of phosphorus vapor, protective gas and / or volatiles in the confined gas phase thermal buffer zone into the buffer cavity; The buffer chamber constitutes a two-stage pressure equalization heat exchange chamber, which is used to equalize the pressure and flow of the gaseous medium that enters through the multiple air guide holes in the buffer chamber, and after exchanging heat with the radiation equalization shroud, it is discharged through the slow-release discharge pipe.

[0012] Preferably, the furnace cover is provided with a thermal state detection device, which is used to detect the thermal state of at least one of the buffer chamber, the confined gas phase thermal buffer zone, the shielding adjustment cover, or the gas phase region near the shielding adjustment cover. The thermal state detection device includes at least one of an infrared thermometer, an optical pyrometer, a dual-color pyrometer, a fiber optic thermometer, or a high-temperature thermocouple.

[0013] Preferably, an upper connecting gap is reserved between the protective sleeve and the radiation homogenization hood, and a lower connecting gap is reserved between the protective sleeve and the bottom of the inner cavity of the furnace body. The atmosphere cavity and the high-temperature cavity are connected through the upper connecting gap and the lower connecting gap. A gas supply pipe communicating with the atmosphere cavity is provided on the furnace cover, and the gas supply pipe is used to supply protective gas into the atmosphere cavity.

[0014] Preferably, a first flow channel is formed between the outer side of the shielding adjustment cover and the main heater and / or the protective sleeve, and a second flow channel is formed between the inner side of the shielding adjustment cover and the crucible; When the annular radiation compensation gap is closed, the upper side of the first flow channel is connected to the upper connecting gap, and the lower side of the second flow channel is connected to the high-temperature cavity; the upper side of the second flow channel is connected to the confined gas phase thermal buffer zone and is configured to allow the gas added to the high-temperature cavity to flow along the outer and inner sides of the shielding adjustment cover respectively, so as to form a double-sided flow heat exchange structure for the shielding adjustment cover.

[0015] Preferably, the confined gas-phase thermal buffer is configured to adapt to changes in the upper space between the crucible opening and the melt surface during crystal growth; As the melt is gradually consumed, the distance between the melt surface and the crucible opening increases, creating an increased upper space between the crucible opening and the melt surface. This increased upper space increases the exposed height of the upper inner wall of the crucible above the melt surface and causes more of the upper inner wall of the crucible to participate in forming the confining boundary of the confined gas phase thermal buffer zone, thereby stabilizing the local thermal boundary of the upper space.

[0016] Preferably, the furnace cover is provided with a lifting channel corresponding to the lifting mechanism, and the seed crystal rod extends into the crucible through the lifting channel; Both the radiation homogenization cover and the shielding adjustment cover are provided with a central clearance channel, which is provided in correspondence with the lifting channel for the seed crystal rod or the growth crystal to pass through. A movable cover is fitted onto the surface of the seed crystal rod, and the movable cover closes onto the lifting channel and can move with the seed crystal rod.

[0017] The present invention has the following beneficial effects: 1. This invention, by setting a radiation homogenizing hood and a shielding adjustment hood above the crucible opening, creates a confined gas-phase thermal buffer zone together with the upper space between the crucible opening and the melt surface. This prevents the crucible opening from being directly exposed to the furnace space, thus avoiding disordered convection and rapid escape of protective gas, phosphorus vapor, and volatiles. Simultaneously, an adjustable annular radiation compensation gap is formed between the shielding adjustment hood and the radiation homogenizing hood, allowing the compensation radiation heat entering this confined gas-phase thermal buffer zone to be adjusted. Therefore, this invention can simultaneously limit gas-phase disturbance at the crucible opening and adjust the compensation radiation heat input at the opening, thereby improving the temperature field stability of the upper space between the crucible opening and the melt surface.

[0018] 2. The confined gas-phase thermal buffer of the present invention can adapt to changes in the upper space between the crucible opening and the melt surface during crystal growth. As the melt is gradually consumed, the distance between the melt surface and the crucible opening increases, creating an enlarged upper space between the crucible opening and the melt surface. This increases the exposed height of the upper inner wall of the crucible above the melt surface, and allows more of the upper inner wall of the crucible to participate in forming the confining boundary of the confined gas-phase thermal buffer. Therefore, the upper inner wall of the crucible can work together with the radiation homogenization shield and the shielding adjustment shield to stabilize the local thermal boundary of the upper space and reduce local temperature fluctuations caused by the expansion of the upper space after the melt surface drops.

[0019] 3. This invention forms an orderly emission path through a gas guide hole, a buffer chamber, a slow-release emission pipe, and a flow regulation component. This allows phosphorus vapor, protective gas, and / or volatiles escaping from the crucible opening to complete retention and heat exchange within a confined gas-phase thermal buffer zone before entering the buffer chamber and being slowly released and guided to the distal condensation zone or collection zone. Compared to the disorderly diffusion, condensation, and deposition of evaporated gases within the furnace, this invention can confine phosphorus vapor and liquid sealing material volatiles within a preset emission path, reducing contamination deposition on components such as the main heater, protective sleeve, furnace cover, and observation window. Simultaneously, it avoids sudden disturbances to the temperature field above the crucible opening during the exhaust process.

[0020] 4. This invention forms a first flow channel and a second flow channel on the outer and inner sides of the shielding adjustment cover, respectively, allowing the gas added to the high-temperature chamber to flow along the outer and inner sides of the shielding adjustment cover, forming a double-sided enclosed heat transfer structure for the shielding adjustment cover. This allows for adjustment of the thermal state of the shielding adjustment cover, reducing the impact of the shielding adjustment cover's own heating or cooling lag on the adjustment effect of the annular radiation compensation gap, enabling the shielding adjustment cover to approach the preset thermal state more quickly, thereby improving the response speed and stability of the local thermal boundary adjustment in the upper space of the crucible opening. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the indium phosphide single crystal growth furnace proposed in this invention. Figure 2 This is a three-dimensional cross-sectional view of the furnace body proposed in this invention; Figure 3 This is a three-dimensional structural diagram of the furnace body proposed in this invention; Figure 4 This is a three-dimensional structural diagram of the furnace lid proposed in this invention; Figure 5 This is a schematic diagram of the cross-sectional structure of the furnace body and furnace cover proposed in this invention; Figure 6 This is a side sectional view of the furnace body and furnace cover proposed in this invention, wherein the annular radiation compensation gap is in a closed or slightly open state; Figure 7This is a side sectional view of the furnace body and furnace cover proposed in this invention, wherein the annular radiation compensation gap is in the open state; Figure 8 This is a side sectional view of the furnace body and furnace cover proposed in this invention, showing the state of the crucible after it has been lifted during the later stages of crystal pulling; Figure 9 This is a schematic cross-sectional view of the radiation homogenization shield and shielding adjustment shield proposed in this invention, showing the first and second flow guiding channels. Figure 10 This is a schematic diagram comparing the crucible states during the early and late stages of crystal pulling, as proposed in this invention.

[0022] In the picture: 100. Furnace body; 101. Main heater; 102. Protective sleeve; 103. Crucible; 104. Lifting and rotating mechanism; 200. Furnace lid; 201. Seed crystal rod; 202. Lifting mechanism; 203. Radiation homogenization cover; 204. Shielding adjustment cover; 205. Drive assembly; 206. Slow-release emission pipe; 207. Flow regulation assembly; 208. Annular radiation compensation gap; 209. Confined gas phase thermal buffer zone; 210. Gas guide hole; 211. Buffer cavity; 212. Thermal state detection device; 213. Gas supply pipe; 214. First flow guide channel; 215. Second flow guide channel; 216. Lifting channel; 217. Movable cover. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0024] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0025] Example 1 See Figures 1 to 5This embodiment provides an indium phosphide single crystal growth furnace, including a furnace body 100 and a furnace cover 200 disposed above the furnace body 100. A main heater 101, a protective sleeve 102, and a crucible 103 are disposed inside the furnace body 100. The protective sleeve 102 surrounds the main heater 101, forming a high-temperature chamber inside the protective sleeve 102. An atmosphere chamber is formed between the protective sleeve 102 and the inner wall of the furnace body 100. The protective sleeve 102 is preferably made of alumina ceramic, but can also be made of boron nitride ceramic, silicon carbide ceramic, silicon carbide coated graphite, or other high-temperature resistant materials. The crucible 103 is disposed inside the high-temperature chamber. A lifting and rotating mechanism 104 is disposed at the bottom of the furnace body 100. The lifting and rotating mechanism 104 is used to drive the crucible 103 to lift and / or rotate, thereby adjusting the position of the crucible 103 relative to the main thermal field formed by the main heater 101.

[0026] See Figure 1 , Figure 2 and Figure 5 The furnace cover 200 is located above the furnace body 100, and the furnace cover 200 is equipped with a lifting mechanism 202 for driving the seed crystal rod 201 to rise and fall. The lifting mechanism 202 can drive the seed crystal rod 201 to extend into the crucible 103, or drive the seed crystal rod 201 and the growing crystal to move upward during the crystal growth process.

[0027] See Figures 2 to 4 The furnace cover 200 has a radiation homogenization hood 203 and a shielding adjustment hood 204 on its lower side, and a drive assembly 205 and a slow-release discharge pipe 206 on its upper side. The drive assembly 205 drives the shielding adjustment hood 204 to move up and down along the axial direction of the crucible 103. The drive assembly 205 may include at least one of a linear motor, an electric push rod, a cylinder, or a hydraulic cylinder. The drive assembly 205 and the shielding adjustment hood 204 can be connected via a high-temperature resistant connecting rod. The slow-release discharge pipe 206 is directly or indirectly connected to the inner cavity of the radiation homogenization hood 203. A flow regulation assembly 207 is provided on the slow-release discharge pipe 206, which is used to regulate the rate at which the gaseous medium is discharged through the slow-release discharge pipe 206. The flow regulation assembly 207 may be at least one of a throttle valve, a needle valve, a pressure regulating valve, a back pressure valve, a rotary valve, or an electric proportional valve.

[0028] See Figures 3 to 7The radiation homogenizing cover 203 has an inner cavity facing the opening of the crucible 103, and is positioned over the upper opening of the protective sleeve 102. A shielding adjustment cover 204 is disposed below the radiation homogenizing cover 203, forming an annular radiation compensation gap 208 between the shielding adjustment cover 204 and the radiation homogenizing cover 203. The annular radiation compensation gap 208 constitutes a local radiation channel for the main heater 101 towards the inner cavity of the radiation homogenizing cover 203. When the shielding adjustment cover 204 moves up and down, it can change the opening area and radiation incident angle range of this local radiation channel, thereby adjusting the compensation radiation heat entering the inner cavity of the radiation homogenizing cover 203.

[0029] See Figure 6 and Figure 10 The inner cavity of the radiation homogenization hood 203 and the shielding adjustment hood 204 together enclose the area above the inlet of the crucible 103 and communicate with the upper space between the inlet of the crucible 103 and the surface of the melt, forming a confined gas phase thermal buffer zone 209. Phosphorus vapors, protective gases and / or volatiles escaping from the inlet of the crucible 103 can remain and diffuse within the confined gas phase thermal buffer zone 209 before being discharged, and exchange heat with the inner wall of the radiation homogenization hood 203 and / or the shielding adjustment hood 204, before being discharged through the slow-release discharge pipe 206.

[0030] It should be noted that the confined gas phase thermal buffer zone 209 is not a completely sealed cavity, but rather a localized gas phase confinement area jointly defined by the radiation homogenization hood 203, the shielding adjustment hood 204, the inlet of crucible 103, and the upper space between the inlet of crucible 103 and the melt surface. This area allows the gas phase medium to be slowly discharged through the gas guide hole 210, the buffer chamber 211, and the slow-release discharge pipe 206, while restricting the disorderly escape of the gas phase medium from the inlet of crucible 103 into the furnace space.

[0031] See Figure 5 The furnace cover 200 is provided with a lifting channel 216 corresponding to the lifting mechanism 202, through which the seed crystal rod 201 extends into the crucible 103. Both the radiation homogenization hood 203 and the shielding adjustment hood 204 can be provided with a central clearance channel, corresponding to the lifting channel 216, for the passage of the seed crystal rod 201 or the grown crystal. A movable cover 217 can be fitted onto the surface of the seed crystal rod 201, covering the lifting channel 216 and moving with the seed crystal rod 201 to reduce atmosphere disturbance and heat loss at the lifting channel 216.

[0032] In this embodiment, the confined gas phase thermal buffer zone 209 prevents the crucible 103 opening from being directly exposed to the furnace space, thereby reducing the disordered convection and rapid escape of protective gas, phosphorus vapor, and volatiles at the crucible 103 opening. Simultaneously, the annular radiation compensation gap 208 regulates the compensation radiation heat entering the radiation homogenization shroud 203, homogenizing the compensation radiation heat and the heat carried by the gas phase medium escaping from the crucible 103 opening within the upper space between the crucible 103 opening and the melt surface, thus stabilizing the local thermal boundary of this upper space.

[0033] Example 2 See Figures 3 to 7 Based on Example 1, this example further illustrates the radiation homogenization shield 203 and the annular radiation compensation gap 208.

[0034] The radiation homogenization shield 203 is a conical shield structure with a smaller top and a larger bottom, and the inner wall of the radiation homogenization shield 203 forms a conical radiation homogenization surface. The conical radiation homogenization surface is positioned facing the opening of the crucible 103 to receive the compensating radiation heat entering through the annular radiation compensation gap 208, and to guide the compensating radiation heat to the upper space between the opening of the crucible 103 and the surface of the melt by means of reflection, diffuse reflection and / or re-radiation.

[0035] See Figure 6 When the shielding adjustment cover 204 moves upward to a position close to the radiation homogenization cover 203, the annular radiation compensation gap 208 is in a closed state or a small opening state. At this time, less compensation radiation heat enters the inner cavity of the radiation homogenization cover 203, and the confined gas phase thermal buffer zone 209 focuses more on confining the gas phase medium, reducing the disordered escape of gas from the crucible 103 or the rapid heat loss.

[0036] See Figure 7 When the shielding adjustment cover 204 moves downward, the annular radiation compensation gap 208 between the shielding adjustment cover 204 and the radiation homogenization cover 203 increases, allowing more of the compensated radiation heat from the main heater 101 to enter the inner cavity of the radiation homogenization cover 203. After entering the inner cavity, the compensated radiation heat is reflected, diffusely reflected, and / or re-radiated by the conical radiation homogenization surface of the radiation homogenization cover 203, and then acts on the upper space between the crucible 103 opening and the melt surface.

[0037] In this embodiment, the vertical movement of the shielding adjustment cover 204 does not directly change the heating of the crucible 103 body by the main heater 101, but rather changes the amount of compensating radiant heat entering the inner cavity of the radiation homogenization cover 203 by adjusting the opening of the annular radiation compensation gap 208. Therefore, localized compensating radiation adjustment can be performed on the upper space of the crucible 103 opening without disrupting the main thermal field of the crucible 103 body.

[0038] In an optional embodiment, the radiation homogenizing shield 203 and / or the shielding adjustment shield 204 may be made of graphite, pyrolytic graphite, carbon / carbon composite material, silicon carbide coated graphite, PBN, molybdenum, tungsten, or a combination thereof. The inner wall of the radiation homogenizing shield 203 may also be provided with a phosphorus vapor corrosion resistant coating to improve its stability in a high-temperature phosphorus-containing atmosphere.

[0039] Example 3 Based on Embodiment 1 or Embodiment 2, this embodiment describes the air guide 210, the buffer chamber 211, and the slow-release emission structure.

[0040] See Figure 3 , Figure 4 , Figure 6 The radiation homogenization hood 203 has multiple air guide holes 210 on its surface. The radiation homogenization hood 203 is fixedly installed on the lower surface of the furnace cover 200, and a buffer cavity 211 is formed between the radiation homogenization hood 203 and the furnace cover 200. The slow-release discharge pipe 206 communicates with the inner cavity of the radiation homogenization hood 203 through the buffer cavity 211 and the air guide holes 210.

[0041] See Figure 6 Phosphorus vapor, protective gas, and / or volatiles escaping from the crucible 103 opening first enter the confined gas phase thermal buffer 209, where they remain, diffuse, and exchange heat with the inner wall of the radiation homogenization hood 203 and / or the shielding regulating hood 204. Subsequently, the gaseous medium enters the buffer chamber 211 through the vent holes 210. Multiple vent holes 210 are preferably distributed circumferentially along the radiation homogenization hood 203, forming throttling orifices. These throttling orifices limit the instantaneous flow rate of the gaseous medium entering the buffer chamber 211 from the confined gas phase thermal buffer 209, preventing the gaseous medium from being directly and rapidly discharged by the slow-release exhaust pipe 206, thereby reducing sudden disturbances to the temperature field above the crucible 103 opening during the exhaust process.

[0042] The buffer chamber 211 constitutes a secondary pressure equalization heat exchange chamber. The gaseous medium entering the buffer chamber 211 through multiple air vents 210 can achieve pressure and flow equalization within the buffer chamber 211, and after heat exchange with the radiation equalization shroud 203 and / or furnace cover 200, it is discharged through the slow-release emission pipe 206. Thus, phosphorus vapor and volatiles from the liquid sealing material can be discharged along a predetermined path, reducing random deposition and contamination on the main heater 101, protective sleeve 102, furnace cover 200, observation window, or other insulation structures.

[0043] See Figure 1 and Figure 5A thermal state detection element 212 may be provided on the furnace cover 200. The thermal state detection element 212 is used to detect the thermal state of at least one of the buffer chamber 211, the confined gas phase thermal buffer zone 209, the shielding adjustment cover 204, or the gas phase region near the shielding adjustment cover 204. The thermal state detection element 212 may be at least one of an infrared thermometer, an optical pyrometer, a dual-color pyrometer, a fiber optic thermometer, or a high-temperature thermocouple.

[0044] The thermal state detection element 212 can be connected to the controller. The controller controls the amount of gas supplied by the flow regulating component 207, the drive component 205 and / or the gas supply pipe 213 according to the detection value of the thermal state detection element 212, so as to adjust the retention of gaseous medium, emission rate, opening of the annular radiation compensation gap 208 and the intensity of double-sided entrained heat transfer.

[0045] This embodiment utilizes the gas phase emission path—including the confined gas phase thermal buffer zone 209, the gas guide hole 210, the buffer chamber 211, and the slow-release emission pipe 206—to ensure that phosphorus vapor, protective gas, and / or volatiles undergo retention, throttling, pressure equalization, flow equalization, and heat exchange before discharge. This not only helps stabilize the thermal boundary of the space above the crucible 103 opening but also reduces in-furnace contamination. Simultaneously, the thermal state detection element 212 can directly or indirectly detect the thermal state of the shielding adjustment cover 204, the confined gas phase thermal buffer zone 209, or the buffer chamber 211, providing a basis for adjusting the drive assembly 205, the flow regulation assembly 207, and the gas supply pipe 213.

[0046] Example 4 See Figure 8 and Figure 9 Based on the above embodiments, this embodiment further describes the first flow guiding channel 214, the second flow guiding channel 215, and the double-sided flow-following heat exchange structure.

[0047] See Figure 8 An upper connecting gap is provided between the protective sleeve 102 and the radiation homogenization hood 203, and a lower connecting gap is provided between the protective sleeve 102 and the bottom of the inner cavity of the furnace body 100. The atmosphere chamber and the high-temperature chamber are connected through the upper and lower connecting gaps. A gas supply pipe 213 communicating with the atmosphere chamber is provided on the furnace cover 200, and the gas supply pipe 213 is used to supply protective gas into the atmosphere chamber.

[0048] See Figure 9 A first flow channel 214 is formed between the outer side of the shielding adjustment cover 204 and the main heater 101 and / or the protective sleeve 102, and a second flow channel 215 is formed between the inner side of the shielding adjustment cover 204 and the crucible 103. When the annular radiation compensation gap 208 is closed, the upper side of the first flow channel 214 is connected to the upper side connecting gap, the lower side of the second flow channel 215 is connected to the high temperature cavity, and the upper side of the second flow channel 215 is connected to the confined gas phase thermal buffer zone 209.

[0049] See Figure 9 When the slow-release discharge pipe 206 discharges the gaseous medium from the confined gaseous thermal buffer zone 209, the protective gas replenished in the atmosphere chamber can enter the high-temperature chamber through the upper and lower connecting gaps. At this time, the annular radiation compensation gap 208 is in the closed state, and the gas entering through the upper connecting gap can flow from top to bottom along the outside of the shielding adjustment cover 204 in the first guide channel 214; the gas entering the high-temperature chamber can flow from bottom to top along the inside of the shielding adjustment cover 204 in the second guide channel 215. The first guide channel 214 and the second guide channel 215 are close to the outside and inside of the shielding adjustment cover 204, respectively, thus forming a double-sided flow heat exchange structure for the shielding adjustment cover 204.

[0050] This double-sided duct heat exchange structure is primarily used to regulate the thermal state of the shielding adjustment cover 204, rather than simply for cooling it. During operation, the shielding adjustment cover 204 receives radiant heat from the main heater 101 and also participates in the re-radiation and gas-phase heat exchange in the upper space above the crucible 103 opening. Therefore, the shielding adjustment cover 204 itself has a certain heat capacity and a temperature response lag. When the opening of the annular radiation compensation gap 208 changes, if the temperature of the shielding adjustment cover 204 cannot promptly approach the preset thermal state, it may cause a delay or overshoot in the compensation heat input to the upper space above the crucible 103 opening.

[0051] In this embodiment, the gas added to the high-temperature chamber flows along the outer and inner sides of the shielding adjustment cover 204 through the first flow channel 214 and the second flow channel 215, respectively, to perform double-sided heat exchange adjustment on the shielding adjustment cover 204. This reduces the impact of the temperature lag of the shielding adjustment cover 204 itself on the adjustment effect of the annular radiation compensation gap 208, and improves the response speed and stability of the local thermal boundary adjustment in the upper space of the crucible 103.

[0052] It should be noted that, see Figure 8 and Figure 10The double-sided ferrule heat exchange structure can be activated or enhanced during the later stages of crystal pulling, after the melt level drops relative to the crucible 103 opening, when the temperature of the shielding adjustment cover 204 deviates from the preset value, or during the cooling stage. As the melt is gradually consumed during crystal growth, the distance between the melt level and the crucible 103 opening increases, creating an increased upper space between the crucible 103 opening and the melt level. This increased upper space increases the exposed height of the upper inner wall of the crucible 103 above the liquid level, and allows more of the upper inner wall of the crucible 103 to participate in forming the confined boundary of the restricted gas phase thermal buffer zone 209. This part of the upper inner wall of the crucible, together with the radiation homogenization cover 203 and the shielding adjustment cover 204, helps to stabilize the local thermal boundary of the upper space. At the same time, due to the reduction in melt volume and the decrease in system heat capacity, the temperature of the upper space is more sensitive to changes in the thermal state of the compensation radiation and the shielding adjustment cover 204. At this time, by adjusting the thermal state of the shielding adjustment cover 204 through the double-sided ferrule heat exchange structure, the influence of the temperature lag or local overheating of the shielding adjustment cover 204 on the temperature field of the upper space between the crucible 103 opening and the melt surface can be reduced.

[0053] Working principle 1. During the heating and melting stage or the initial heat preservation stage, please refer to... Figure 2 , Figure 5 As the material inside crucible 103 gradually heats up, phosphorus vapor, protective gas, and / or volatiles of the liquid sealing material begin to escape from the opening of crucible 103. At this time, the shielding adjustment cover 204 can be controlled to move upward, so that the annular radiation compensation gap 208 is in a closed state or a small opening state, thereby reducing the direct communication between the opening of crucible 103 and the furnace space, and enhancing the confinement effect of the confined gas phase thermal buffer zone 209 on the gas phase medium at the crucible opening. After the escaped gas phase medium is retained, diffused, and heat-exchanged in the confined gas phase thermal buffer zone 209, it enters the buffer chamber 211 through the gas guide hole 210, and is then slowly discharged through the slow-release discharge pipe 206.

[0054] During the above-mentioned emission process, the emission rate of the slow-release emission pipe 206 can be adjusted by the flow regulating component 207, and protective gas can be introduced into the atmosphere chamber through the gas supply pipe 213, so that the high-temperature chamber and the atmosphere chamber form an appropriate gas supply pressure difference. The protective gas in the atmosphere chamber can be introduced into the high-temperature chamber through the upper connecting gap and / or the lower connecting gap, forming a gas supply flow from the atmosphere chamber to the high-temperature chamber, which suppresses the disorderly outflow of phosphorus vapor and volatiles from the mouth of the crucible 103 into the atmosphere chamber, thereby reducing phosphorus vapor pollution.

[0055] 2. In the early stages of crystal pulling, see... Figure 10The melt level inside crucible 103 is relatively high, and the upper space between the crucible 103 opening and the melt level is relatively small. At this time, the confined gaseous thermal buffer zone 209 formed by the radiation homogenization hood 203 and the shielding adjustment hood 204 is mainly used to confine the gaseous medium at the crucible 103 opening, stabilize the gaseous environment at the crucible 103 opening, and prevent the crucible opening from being directly exposed to the furnace space, thus avoiding disordered convection and rapid heat loss. The annular radiation compensation gap 208 can maintain a small or medium opening, making the compensated radiant heat entering the inner cavity of the radiation homogenization hood 203 relatively gradual, thereby maintaining the stability of the local thermal boundary in the upper space above the crucible opening.

[0056] In the later stages of crystal pulling, see Figure 10 As the crystal pulling process proceeds, the crystal is continuously pulled, and the melt inside the crucible 103 is gradually consumed. Even though the lifting and rotating mechanism 104 drives the crucible 103 upward, keeping the position of the melt surface relative to the main thermal field in the furnace within a preset range, the melt surface still tends to decrease relative to the opening of the crucible 103, creating an increased upper space between the opening of the crucible 103 and the melt surface. This increased upper space increases the exposed height of the upper inner wall of the crucible 103 above the melt surface, and causes more of the upper inner wall of the crucible 103 to participate in forming the confined boundary of the restricted gas phase thermal buffer zone 209. Compared with the early stage of crystal pulling, the proportion of this part of the upper inner wall of the crucible participating in the thermal boundary of the upper space increases, and together with the radiation homogenization shield 203 and the shielding adjustment shield 204, it helps to stabilize the local thermal boundary of the upper space between the opening of the crucible 103 and the melt surface. At this time, the position of the shielding adjustment cover 204 can be adjusted by controlling the drive component 205 according to the temperature of the upper space between the crucible 103 opening and the melt surface, the temperature of the buffer chamber 211, the thermal state of the shielding adjustment cover 204, the crystal pulling length, the melt surface drop, the phosphorus vapor emission, or the preset process curve, thereby changing the opening degree of the annular radiation compensation gap 208.

[0057] Specifically, when it is necessary to increase the compensating radiative heat input in the space above the crucible 103 opening, the shielding adjustment cover 204 can be moved downwards, increasing the annular radiative compensation gap 208; when it is necessary to reduce the compensating radiative heat input, enhance the gas phase retention buffer, or restrict the rapid escape of volatiles from the crucible opening, the shielding adjustment cover 204 can be moved upwards, decreasing the annular radiative compensation gap 208. Thus, the annular radiative compensation gap 208, the inner cavity of the radiative homogenization cover 203, and the confined gas phase thermal buffer 209 together form a synergistic adjustment structure for radiative compensation and gas phase thermal buffer, so that the compensating radiative heat and the heat carried by the gas phase medium escaping from the crucible opening are homogenized in the upper space between the crucible 103 opening and the melt surface.

[0058] See Figure 8 , Figure 9When the thermal state of the shielding adjustment cover 204 deviates from the preset range, or when the shielding adjustment cover 204 exhibits a temperature response lag due to the absorption of radiant heat, the protective gas can flow along the first guide channel 214 and the second guide channel 215 respectively, performing double-sided flow heat exchange on the outer and inner sides of the shielding adjustment cover 204. In this way, the thermal state of the shielding adjustment cover 204 can be adjusted, allowing it to approach the preset thermal state more quickly, thus reducing the impact of the temperature lag of the shielding adjustment cover 204 on the adjustment effect of the annular radiation compensation gap 208.

[0059] 3. During the cooling stage after crystal pulling, exhaust gas is released through the slow-release exhaust pipe 206, allowing residual phosphorus vapor, protective gas and / or volatiles to be guided to the far-end condensation zone or collection zone along a preset path through the confined gas phase thermal buffer zone 209, the gas guide hole 210, the buffer chamber 211 and the slow-release exhaust pipe 206, thereby reducing the random deposition of volatiles in the furnace and reducing equipment pollution.

[0060] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An indium phosphide single crystal growth furnace, characterized in that, include: A furnace body (100) is provided with a main heater (101), a protective sleeve (102) and a crucible (103). The protective sleeve (102) surrounds the outside of the main heater (101). A high-temperature chamber is formed inside the protective sleeve (102). An atmosphere chamber is formed between the protective sleeve (102) and the inner wall of the furnace body (100). The crucible (103) is placed inside the high-temperature chamber. A lifting and rotating mechanism (104) supporting the crucible (103) is provided at the bottom of the furnace body (100). A furnace cover (200) is disposed above the furnace body (100). The furnace cover (200) is provided with a lifting mechanism (202) for driving the seed crystal rod (201) to rise and fall. A radiation homogenization hood (203) and a shielding adjustment hood (204) are disposed on the lower side of the furnace cover (200). A driving assembly (205) and a slow-release discharge pipe (206) are disposed on the upper side of the furnace cover (200). The driving assembly (205) is used to drive the shielding adjustment hood (204) to move up and down along the axial direction of the crucible (103). The slow-release discharge pipe (206) is directly or indirectly connected to the inner cavity of the radiation homogenization hood (203), and a flow rate adjustment assembly (207) is disposed on the slow-release discharge pipe (206). The radiation homogenizing cover (203) has an inner cavity facing the crucible (103) opening. The radiation homogenizing cover (203) is placed over the upper opening of the protective sleeve (102). The shielding adjustment cover (204) is disposed on the lower side of the radiation homogenizing cover (203). An annular radiation compensation gap (208) is formed between the shielding adjustment cover (204) and the radiation homogenizing cover (203). The annular radiation compensation gap (208) is used to allow the main heater (101) to input compensating radiation heat into the inner cavity of the radiation homogenization cover (203), and the shielding adjustment cover (204) moves up and down to adjust the opening of the annular radiation compensation gap (208). The inner cavity of the radiation homogenization hood (203) and the shielding adjustment hood (204) together enclose the area above the crucible (103) opening and communicate with the upper space between the crucible (103) opening and the melt surface to form a confined gas phase thermal buffer zone (209). The confined gas phase thermal buffer zone (209) is used to allow the phosphorus vapor, protective gas and / or volatiles escaping from the crucible (103) to be retained, diffused and exchange heat with the inner wall of the radiation homogenization hood (203) and / or the shielding adjustment hood (204) before being discharged. The gas phase heat exchange state in the confined gas phase thermal buffer zone (209) changes with the opening of the annular radiation compensation gap (208) to homogenize the compensation radiation heat and the heat carried by the gas phase medium escaping from the crucible (103) in the upper space between the crucible (103) opening and the melt surface.

2. The indium phosphide single crystal growth furnace according to claim 1, characterized in that: The radiation homogenizing cover (203) is a conical cover structure with a smaller top and a larger bottom. The inner wall of the radiation homogenizing cover (203) forms a conical radiation homogenizing surface. The conical radiation homogenizing surface is used to receive the compensating radiation heat entering through the annular radiation compensation gap (208) and guide the compensating radiation heat to the upper space between the crucible (103) opening and the melt surface in the manner of reflection, diffuse reflection and / or re-radiation.

3. The indium phosphide single crystal growth furnace according to claim 1, characterized in that: The surface of the radiation homogenization hood (203) is provided with a plurality of air guide holes (210). The radiation homogenization hood (203) is fixedly installed on the lower surface of the furnace cover (200), and a buffer cavity (211) is formed between the radiation homogenization hood (203) and the furnace cover (200). The slow-release discharge pipe (206) communicates with the inner cavity of the radiation homogenization hood (203) through the buffer cavity (211) and the air guide holes (210), so that the phosphorus vapor, protective gas and / or volatiles in the restricted gas phase thermal buffer zone (209) enter the buffer cavity (211) through the air guide holes (210) and are then discharged through the slow-release discharge pipe (206).

4. The indium phosphide single crystal growth furnace according to claim 3, characterized in that: The plurality of air guide holes (210) are distributed circumferentially along the radiation homogenization shield (203). The air guide holes (210) constitute throttling holes to limit the instantaneous flow rate of phosphorus vapor, protective gas and / or volatiles in the confined gas phase thermal buffer (209) into the buffer chamber (211). The buffer chamber (211) constitutes a secondary pressure equalization heat exchange chamber, which is used to equalize the pressure and flow of the gaseous medium entering through the multiple air guide holes (210) in the buffer chamber (211), and after exchanging heat with the radiation equalization cover (203), it is discharged through the slow release discharge pipe (206).

5. An indium phosphide single crystal growth furnace according to claim 3, characterized in that: A thermal state detection element (212) is provided on the furnace cover (200). The thermal state detection element (212) is used to detect the thermal state of at least one of the buffer chamber (211), the confined gas phase thermal buffer zone (209), the shielding adjustment cover (204), or the gas phase region near the shielding adjustment cover (204). The thermal state detection element (212) includes at least one of an infrared thermometer, an optical pyrometer, a dual-color pyrometer, a fiber optic thermometer, or a high-temperature thermocouple.

6. The indium phosphide single crystal growth furnace according to claim 1, characterized in that: An upper connecting gap is reserved between the protective sleeve (102) and the radiation homogenization hood (203), and a lower connecting gap is reserved between the protective sleeve (102) and the bottom of the inner cavity of the furnace body (100). The atmosphere cavity and the high temperature cavity are connected through the upper connecting gap and the lower connecting gap. A gas supply pipe (213) connected to the atmosphere cavity is provided on the furnace cover (200), and the gas supply pipe (213) is used to supply protective gas into the atmosphere cavity.

7. An indium phosphide single crystal growth furnace according to claim 6, characterized in that: A first flow channel (214) is formed between the outer side of the shielding adjustment cover (204) and the main heater (101) and / or the protective sleeve (102), and a second flow channel (215) is formed between the inner side of the shielding adjustment cover (204) and the crucible (103). When the annular radiation compensation gap (208) is closed, the upper side of the first flow channel (214) is connected to the upper side communication gap, and the lower side of the second flow channel (215) is connected to the high temperature cavity; the upper side of the second flow channel (215) is connected to the confined gas phase thermal buffer zone (209) and is configured to allow the gas added to the high temperature cavity to flow along the outer and inner sides of the shielding adjustment cover (204) respectively, so as to form a double-sided flow heat exchange structure for the shielding adjustment cover (204).

8. The indium phosphide single crystal growth furnace according to claim 1, characterized in that: The confined gas phase thermal buffer zone (209) is configured to accommodate changes in the upper space between the crucible (103) opening and the melt surface during crystal growth; As the melt is gradually consumed, the distance between the melt surface and the crucible (103) opening increases, creating an increased upper space between the crucible (103) opening and the melt surface. This increased upper space increases the exposed height of the upper inner wall of the crucible (103) above the liquid surface and causes more of the upper inner wall of the crucible (103) to participate in forming the confining boundary of the confined gas phase thermal buffer zone (209), thereby stabilizing the local thermal boundary of the upper space.

9. An indium phosphide single crystal growth furnace according to claim 1, characterized in that: The furnace cover (200) is provided with a lifting channel (216) corresponding to the lifting mechanism (202), and the seed crystal rod (201) extends into the crucible (103) through the lifting channel (216); Both the radiation homogenization cover (203) and the shielding adjustment cover (204) are provided with a central clearance channel, which is provided in correspondence with the lifting channel (216) for the seed crystal rod (201) or the growth crystal to pass through. The surface of the seed crystal rod (201) is fitted with a movable cover (217), which covers the lifting channel (216) and can move with the seed crystal rod (201).

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