Thermal field structure of gallium oxide crystal growing furnace

Abstract

The utility model discloses a thermal field structure of a gallium oxide crystal growing furnace, which relates to the technical field of crystal growth and comprises a crystal growing furnace, a vertical channel hole communicated with a furnace chamber is arranged at the bottom of the crystal growing furnace; the silicon molybdenum rod heater is arranged in the furnace chamber; the crucible can penetrate through the vertical channel hole to enter the furnace chamber; the lifting driving mechanism is used for driving the crucible to enter the furnace chamber through the vertical channel hole or leave the furnace chamber through the vertical channel hole; the heat preservation element comprises a heat preservation partition plate and a heat preservation column. After the crucible is withdrawn from the furnace chamber, the heat-insulating partition plate can cover the top end of the vertical channel hole, so that on one hand, the temperatures of the crucible and crystals are effectively reduced, and the quality of the crystals is improved; on the other hand, heat in the furnace chamber can be effectively prevented from being dissipated through the vertical channel holes, the temperature in the furnace is more stable, and the temperature of the silicon-molybdenum rod heater in the discharging stage is maintained, so that the silicon-molybdenum rod heater is prevented from cracking due to the fact that the temperature is reduced to a cold brittle state.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of crystal growth, in particular to a thermal field structure of gallium oxide crystal growth furnace. BACKGROUND

[0002] In today's scientific and technological development, high-temperature oxide crystals, as the basic materials for producing various power electronic devices, detectors and sensors, play a crucial role in scientific and industrial fields due to their diverse types and varying properties. High-temperature oxide crystal growth generally requires an inert gas protection or vacuum environment, but gallium oxide can only be grown in an oxygen-containing atmosphere due to its high-temperature decomposition characteristics. In addition, its melting point is as high as 1793℃, so early research and production had to use iridium materials as containers and heaters, and the edge-defined film-fed method and the vertical pulling method were the commonly used technical means at that time.

[0003] With higher requirements for crystal quality and yield, the vertical Bridgman method (VB method) has attracted the attention of researchers. The basic principle of the vertical Bridgman method (VB method) is to place the material to be grown in a container, gradually melt it by heating, and then lower the temperature at the bottom of the crucible to near the melting point, and then the crystal gradually grows from the bottom. The equipment used for crystal growth by VB method is called vertical Bridgman furnace or VB furnace. VB method has the advantages of large production capacity, easy control of crystal shape, and high degree of automation of equipment.

[0004] However, due to the particularity of gallium oxide crystal growth, the selection of high-temperature devices in the VB furnace and the optimization of the thermal field structure have become the focus of research. Under the current high-temperature and high-oxygen atmosphere, silicon molybdenum is the only available heater material, but the silicon molybdenum rod heater has the defect of being prone to cracking during cooling to room temperature, which has been widely verified. The cracking of the silicon molybdenum rod heater will lead to: ① excessive loss and high material cost; ② the need to reinstall after cracking, which is time-consuming and labor-intensive, low in production efficiency, and high in personnel cost; ③ the replacement of the heater leads to uncontrollable differences between crystal growth batches. UTILITY MODEL CONTENTS

[0005] The purpose of the utility model is to provide a thermal field structure of gallium oxide crystal growth furnace to solve the problems existing in the prior art and avoid cracking of the silicon molybdenum rod heater.

[0006] To achieve the above-mentioned purpose, the utility model provides the following scheme:

[0007] The utility model provides a thermal field structure of gallium oxide crystal growth furnace, which comprises:

[0008] A crystal growth furnace, a vertical passage hole communicating with a furnace cavity of the crystal growth furnace is arranged at the bottom of the crystal growth furnace;

[0009] A silicon-molybdenum rod heater is arranged in the furnace cavity.

[0010] A crucible is capable of passing through the vertical passage hole into the furnace cavity.

[0011] A lifting driving mechanism is used to drive the crucible to pass through the vertical passage hole into or out of the furnace cavity.

[0012] A heat preservation element comprises heat preservation partitions and heat preservation columns arranged in sequence from top to bottom, the top end of the heat preservation column is fixedly connected with the heat preservation partition, the bottom end of the heat preservation column is in contact with the top end of the crucible, the heat preservation partition is located in the furnace cavity, and the heat preservation partition cannot pass through the vertical passage hole, and the heat preservation partition is used to cover the top end of the vertical passage hole.

[0013] Preferably, a pull rod is further arranged, the top of the crystal growth furnace is provided with a through hole communicating with the furnace cavity, the pull rod passes through the through hole, and the bottom end of the pull rod is fixedly connected with the heat preservation partition and the top end is located outside the crystal growth furnace.

[0014] Preferably, the heat preservation column is capable of entering the vertical passage hole.

[0015] Preferably, the area of the heat preservation partition is greater than the cross-sectional area of the top end of the vertical passage hole.

[0016] Preferably, the vertical passage hole is in a cylindrical shape, and the heat preservation partition is in a circular shape.

[0017] Preferably, the vertical passage hole, the heat preservation column and the heat preservation partition are coaxial.

[0018] Preferably, the heat preservation partition and the heat preservation column are integrally formed.

[0019] Preferably, the number of the silicon-molybdenum rod heaters is at least three.

[0020] Preferably, all the silicon-molybdenum rod heaters are uniformly distributed along the circumference of the furnace cavity.

[0021] Preferably, the materials of the heat preservation partition and the heat preservation column are both zirconia fibers.

[0022] The utility model discloses the following technical effects are obtained relative to prior art:

[0023] The heat field structure of the gallium oxide crystal growth furnace is provided with a heat preservation element, the heat preservation partition plate covers the top end of the vertical passage hole, and the heat preservation column is in contact with the top end of the crucible, thereby achieving the following effects: on the one hand, the furnace cavity and the crucible are separated, the high temperature in the furnace cavity is prevented from continuing to radiate and heat the crucible, the cooling efficiency of the crucible and the crystal is effectively improved, and the quality of the crystal is improved; on the other hand, the heat in the furnace cavity is effectively prevented from being lost through the vertical passage hole, the temperature in the furnace is more stable, the temperature of the silicon-molybdenum rod heater in the discharging stage is maintained, and the silicon-molybdenum rod heater is prevented from cracking due to the temperature being reduced to a cold brittle state, the problem of the silicon-molybdenum rod heater being prone to cracking is solved, the loss is reduced, and the material cost is saved.

[0024] Further, the solution to the cracking problem of the silicon-molybdenum rod heater reduces the number of times of reinstallation due to the cracking of the heater, saves time and manpower, improves production efficiency, and reduces personnel cost.

[0025] Further, since the silicon-molybdenum rod heater no longer cracks and is replaced frequently, the heat field environment between crystal growth batches is more stable, the difference between crystal growth batches caused by replacement of the heater is reduced, the controllability between crystal growth batches is improved, and the quality and consistency of the crystal are improved.

[0026] Further, the setting of the pull rod enables the heat preservation partition plate to be operated outside the crystal growth furnace through the pull rod, the position and state of the heat preservation element are convenient to adjust, and the operation and control of the crystal growth furnace are facilitated.

[0027] Further, the heat preservation partition plate and the heat preservation column are made of zirconia fiber material and have good high-temperature resistance and heat preservation performance, can effectively block the loss of heat, maintain a high-temperature environment in the furnace cavity, and provide stable heat field conditions for the growth of gallium oxide crystals.

[0028] Further, the number of the silicon-molybdenum rod heaters is at least three and the silicon-molybdenum rod heaters are uniformly distributed along the circumference of the furnace cavity, which can make the heat distribution in the furnace cavity more uniform, avoid local overheating or overcooling, and be beneficial to the uniform growth of gallium oxide crystals and improve the quality of the crystals.

[0029] Further, the lifting driving mechanism can be a combination of a ball screw and a servo motor lifting rod, and the lifting rod is driven to lift by the servo motor to drive the crucible to move up and down. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical schemes in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0031] Figure 1 Structure diagram of the thermal field structure of the gallium oxide crystal growth furnace of the first embodiment of the present application Figure 1 ;

[0032] Figure 2 Structure diagram of the thermal field structure of the gallium oxide crystal growth furnace of the first embodiment of the present application Figure 2 ;

[0033] Figure 3 Structure diagram of the thermal field structure of the gallium oxide crystal growth furnace of the first embodiment of the present application Figure 3 ;

[0034] Figure 4 Structure diagram of the thermal field structure of the gallium oxide crystal growth furnace of the second embodiment of the present application

[0035] In the figure: 1, crystal growth furnace; 2, furnace cavity; 3, silicon molybdenum rod heater; 4, heat preservation partition; 5, heat preservation column; 6, crucible; 7, lifting rod; 8, vertical passage hole; 9, pull rod. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0037] The purpose of the present application is to provide a thermal field structure of a gallium oxide crystal growth furnace to solve the problems in the prior art and avoid cracking of the silicon molybdenum rod heater.

[0038] To make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be described in further detail below with reference to the drawings and specific embodiments.

[0039] Embodiment one

[0040] As shown in the drawings, the present embodiment provides a thermal field structure of a gallium oxide crystal growth furnace, comprising: Figures 1 to 3

[0041] A crystal growth furnace 1, the bottom of the crystal growth furnace 1 is provided with a vertical passage hole 8 communicating with the furnace cavity 2 of the crystal growth furnace 1;

[0042] A silicon molybdenum rod heater 3, the silicon molybdenum rod heater 3 is arranged in the furnace cavity 2;

[0043] A crucible 6, the crucible 6 can pass through the vertical passage hole 8 into the furnace cavity 2; ​

[0044] a lifting drive mechanism for driving the crucible 6 into or out of the furnace chamber 2 through the vertical passage hole 8;

[0045] a heat preservation element, which comprises a heat preservation partition plate 4 and a heat preservation column 5 arranged in sequence from top to bottom, the top end of the heat preservation column 5 is fixedly connected with the heat preservation partition plate 4, the bottom end of the heat preservation column 5 is in contact with the top end of the crucible 6, the heat preservation partition plate 4 is located in the furnace chamber 2 and cannot pass through the vertical passage hole 8, and the heat preservation partition plate 4 is used for covering the top end of the vertical passage hole 8.

[0046] The embodiment sets the heat preservation element, the heat preservation partition plate 4 covers the top end of the vertical passage hole 8, and the heat preservation column 5 is in contact with the top end of the crucible 6, which can cut off the furnace chamber 2 and the crucible 6 on the one hand, avoid the high temperature in the furnace chamber 2 from continuing to radiate and heat the crucible 6, effectively improve the cooling efficiency of the crucible 6 and the crystal in the crucible 6, and improve the quality of the crystal; on the other hand, it can effectively prevent the heat in the furnace chamber 2 from being dissipated through the vertical passage hole, make the temperature in the furnace more stable, maintain the temperature of the silicon-molybdenum rod heater 3 in the discharging stage, thereby avoiding the problem of cracking due to the temperature decreasing to a cold brittle state, reduce the loss, and save the material cost.

[0047] Specifically, the heat preservation column 5 can enter the vertical passage hole 8, and the vertical passage hole 8 is one of the channels through which the furnace chamber 2 and the outside may exchange heat. The heat preservation column 5 can enter the vertical passage hole 8, which can further fill the channel space, effectively reduce the heat convection, block part of the path through which the heat in the furnace chamber 2 exchanges heat with the outside through the vertical passage hole 8, reduce the heat dissipation rate, make the temperature in the furnace chamber 2 more stable, and provide a more suitable thermal environment for the growth of gallium oxide crystals; the heat preservation column 5 entering the vertical passage hole 8 can optimize the temperature distribution of the area near the channel hole at the bottom of the furnace chamber 2. Make the temperature of this area more uniform, avoid the uneven temperature of the bottom of the crucible 6 due to heat dissipation at the channel hole, affect the quality of crystal growth, ensure that the growth conditions of each part of the crystal during the growth process are similar, and be beneficial to improve the uniformity and quality of the crystal.

[0048] The crucible 6 needs to be driven by the lifting drive mechanism to enter or leave the furnace chamber 2 through the vertical passage hole 8. The design that the heat preservation column 5 can enter the vertical passage hole 8 does not hinder the normal lifting movement of the crucible 6 while ensuring the heat preservation effect. It ensures that the key crystal growth step of the crucible 6 descending in the vertical Bridgman method (VB method) can be smoothly carried out, and guarantees the continuity and stability of the crystal growth process.

[0049] The heat preservation column 5 can enter the vertical passage hole 8 to make the heat preservation column 5 and the vertical passage hole 8 spatially matched with each other, effectively utilize the space in the vertical passage hole 8, and make the whole thermal field structure layout more compact and reasonable. In the case of not additionally increasing the volume of the crystal growth furnace 1, the combination of the good heat preservation function and the crucible 6 movement function is realized, which is beneficial to the miniaturization and integration design of the whole structure of the crystal growth furnace 1.

[0050] In the embodiment, specifically, the area of the heat preservation partition plate 4 is greater than the cross-sectional area of the top end of the vertical passage hole 8; the vertical passage hole 8 is in a cylindrical shape, and the heat preservation partition plate 4 is in a circular shape; the vertical passage hole 8, the heat preservation column 5 and the heat preservation partition plate 4 are coaxial, and when the vertical passage hole 8, the heat preservation column 5 and the heat preservation partition plate 4 are coaxial, a relatively regular and closed heat preservation structure can be formed. The heat preservation partition plate 4 can completely cover the top end of the vertical passage hole 8, and the heat preservation column 5 is closely matched with the vertical passage hole 8 to avoid the heat loss gap caused by the structural asymmetry. The coaxial design maximally reduces the channel for the furnace cavity 2 to exchange heat with the outside through the vertical passage hole 8, so that the high-temperature environment in the furnace cavity 2 can be better maintained.

[0051] In the optional scheme of the embodiment, preferably, the heat preservation partition plate 4 and the heat preservation column 5 are integrally formed, and there is no connecting gap between the heat preservation partition plate 4 and the heat preservation column 5. In the thermal field structure of the crystal growth furnace 1, heat is easily conducted through the gap. The integrally formed structure eliminates the potential heat conduction channel, so that the heat is more effectively blocked in the process of transferring from the inside of the furnace cavity 2 to the outside through the vertical passage hole 8. This helps to maintain the high-temperature environment in the furnace cavity 2, provides a stable thermal field for gallium oxide crystal growth, and thus improves the quality and efficiency of crystal growth.

[0052] In the optional scheme of the embodiment, preferably, the number of the silicon molybdenum rod heaters 3 is at least three, and all the silicon molybdenum rod heaters 3 are uniformly distributed along the circumference of the furnace cavity 2, which can make the heat distribution in the furnace cavity 2 more uniform, avoid local overheating or overcooling, and be beneficial to the uniform growth of gallium oxide crystals and improve the quality of the crystals.

[0053] In the optional scheme of the embodiment, preferably, the materials of the heat preservation partition plate 4 and the heat preservation column 5 are both zirconia fibers, which have good high-temperature resistance and heat preservation performance, can effectively block the heat loss, and maintain the high-temperature environment in the furnace cavity 2 to provide stable thermal field conditions for the growth of gallium oxide crystals.

[0054] In the optional scheme of this embodiment, the preferred method is to use a combination of ball screw and servo motor for the lifting drive mechanism, so that the lifting rod 7 installed on the ball screw slider is vertical, the crucible 6 is fixedly connected to the top of the lifting rod 7, and the screw in the ball screw is driven to rotate by the servo motor, thereby driving the lifting rod 7 to rise and fall. The movement of the lifting rod 7 drives the crucible 6 to move up and down.

[0055] The specific usage method of the thermal field structure of the gallium oxide crystal growth furnace in this embodiment is as follows:

[0056] ① When crystal growth is required, first, crystal growth raw materials are loaded into crucible 6. Then, the position of crucible 6 is gradually raised through a lifting drive mechanism until the bottom end of crucible 6 contacts the T-shaped insulation column 5. As crucible 6 rises further, it will push up the insulation column 5, ensuring that both crucible 6 and the insulation element are in the set positions within the furnace cavity 2. Then, the temperature inside the furnace cavity 2 is raised to the melting temperature using the silicon molybdenum rod heater 3, and crystal growth begins. Figure 1 As shown, the insulation element being located at a high position does not affect the heating efficiency.

[0057] ② After crystal growth is completed, the furnace temperature is slowly reduced to 300℃~800℃ according to the cooling process; when the furnace temperature reaches the target value, the crucible 6 is gradually lowered using the lifting drive mechanism. Figure 2 Positioned until the insulation partition 4 covers the top of the vertical channel hole 8, at which point the furnace hot zone is successfully sealed. This allows the silicon molybdenum rod heater 3 to maintain the furnace temperature at 300℃~800℃ with lower power, eliminating the need for further cooling;

[0058] ③ The crucible 6 is driven to descend further by the lifting drive mechanism until it is completely removed from the vertical channel hole 8 and moved to the loading and unloading position, such as... Figure 3 As shown, the temperature of crucible 6 is approximately 50℃~150℃ at this time. After waiting for a while at room temperature, the crystal grown in crucible 6 can be successfully removed.

[0059] ④ Repeat steps ① to ③ to begin a new round of crystal growth.

[0060] Example 2

[0061] like Figure 4 As shown, this embodiment provides a thermal field structure for a gallium oxide crystal growth furnace. The thermal field structure of the gallium oxide crystal growth furnace in this embodiment is basically the same as that of the gallium oxide crystal growth furnace in Embodiment 1 in terms of structure and working principle, with the only difference being:

[0062] The thermal field structure of the gallium oxide crystal growth furnace in this embodiment also includes a pull rod 9. The top of the crystal growth furnace 1 is provided with a through hole communicating with the furnace cavity 2. The pull rod 9 passes through the through hole, and the bottom end of the pull rod 9 is fixedly connected to the heat insulation partition 4, while the top end is located outside the crystal growth furnace 1.

[0063] The setting of the pull rod 9 in the embodiment enables the staff to actively adjust the positions of the heat preservation partition plate 4 and the heat preservation column 5 through the pull rod 9, so that the position and state of the heat preservation element are adjusted conveniently, and the operation is facilitated.

[0064] The principle and implementation mode of the present application are described by using specific examples in the present application, and the above embodiment is only used to help understand the method and core idea of the present application; meanwhile, for the general technical personnel in the field, according to the idea of the present application, the specific implementation mode and application range will be changed. In conclusion, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A heat field structure of a gallium oxide crystal growth furnace, characterized by, The crystal growth furnace comprises: a crystal growth furnace provided with a vertical passage hole in communication with a furnace cavity of the crystal growth furnace at a bottom of the crystal growth furnace; a silicon-molybdenum rod heater arranged in the furnace cavity; a crucible capable of entering the furnace cavity through the vertical passage hole; a lifting driving mechanism for driving the crucible to enter or exit the furnace cavity through the vertical passage hole; a heat preservation element comprising a heat preservation partition plate and a heat preservation column arranged in sequence from top to bottom, a top end of the heat preservation column being fixedly connected with the heat preservation partition plate, a bottom end of the heat preservation column being in contact with a top end of the crucible, the heat preservation partition plate being arranged in the furnace cavity and being unable to pass through the vertical passage hole, the heat preservation partition plate being used for covering a top end of the vertical passage hole.

2. The hot zone structure of a gallium oxide crystal growth furnace according to claim 1, characterized by: A pull rod is further arranged, a through hole in communication with the furnace cavity is arranged at a top of the crystal growth furnace, the pull rod passes through the through hole, and a bottom end of the pull rod is fixedly connected with the heat preservation partition plate and a top end of the pull rod is located outside the crystal growth furnace.

3. The hot field structure of a gallium oxide crystal growing furnace according to claim 1 or 2, characterized in that: The heat preservation column is capable of entering the vertical passage hole.

4. The hot field structure of a gallium oxide crystal growing furnace according to claim 1 or 2, characterized in that: An area of the heat preservation partition plate is greater than a cross-sectional area of the top end of the vertical passage hole.

5. The hot zone structure of a gallium oxide crystal growth furnace according to claim 1 or 2, characterized by: The vertical passage hole is in a cylindrical shape, and the heat preservation partition plate is in a circular shape.

6. The hot zone structure of a gallium oxide crystal growth furnace according to claim 1 or 2, characterized by: The vertical passage hole, the heat preservation column and the heat preservation partition plate are coaxial.

7. The hot zone structure of a gallium oxide crystal growth furnace according to claim 1 or 2, characterized by: The heat preservation partition plate and the heat preservation column are integrally formed.

8. The hot zone structure of a gallium oxide crystal growth furnace according to claim 1 or 2, characterized by: The number of the silicon-molybdenum rod heaters is at least three.

9. The hot zone structure of a gallium oxide crystal growth furnace of claim 8, wherein: All the silicon-molybdenum rod heaters are uniformly distributed along a circumference of the furnace cavity.

10. The hot zone structure of a gallium oxide crystal growth furnace as claimed in claim 1 or 2, characterized by: Both the heat preservation partition plate and the heat preservation column are made of zirconia fiber.

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