An in-situ annealing apparatus, a control method and operating steps for in-situ annealing

Abstract

The application provides an in-situ annealing device used in cooperation with a growth device, the growth device comprising a hollow furnace body, a hot field provided with an open cavity, a crucible and a seed rod, the hot field being contained in the hollow furnace body for providing a gradient heat source in a growth direction, the crucible being contained in the open cavity of the hot field, the seed rod being used for providing a cold source, the seed rod being connected with the crucible to make the crucible move along the growth direction to realize crystal growth, the in-situ annealing device comprising a connected base and a lifting part, the base being contained in the open cavity for selectively supporting the crucible, the lifting part being used for driving the base to move along the growth direction, the seed rod being detachably connected with the crucible, a protruding piece being arranged on the inner wall of the hot field to abut against the base to form an annealing space, wherein when the growth device is in a state of completing crystal growth, the lifting part controls the base to move in a direction opposite to the direction of crystal growth to make the crucible separate from the seed rod, until the base contacts with the protruding piece to form the annealing space for completing annealing.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of crucible lowering method crystal growth and annealing, in particular to an in-situ annealing device, an in-situ annealing control method and operation steps, and is especially suitable for large-size, low-stress fluoride crystal growth. BACKGROUND

[0002] The crucible lowering method is the most important crystal growth method at present due to its high degree of automation and the advantages that the growth process does not need real-time adjustment. For example, CN 215713512 U proposes a device for growing fluoride crystals by the crucible rotation lowering method. However, the driving force for crystallization by the crucible lowering method mainly relies on the temperature gradient provided by the heat field 120 and the cold source provided by the seed rod. Generally, the larger the crystal diameter, the greater the temperature gradient of the heat field 120, and the stronger the cold source of the seed rod. After the crystal growth is completed, the thermal stress generated in the crystal is also larger. At the same time, in order to protect the seed rod, a cold source needs to be continuously supplied in the seed rod after the crystal growth is completed, which aggravates the thermal stress in the crystal. The existence of these thermal stresses induces crystal defects and even causes the crystal to crack.

[0003] In the prior art, in order to eliminate the thermal stress in the crystal, the crystal needs to be taken out after the growth is completed, and the crystal is separated from the seed rod before the crystal is subjected to post-annealing treatment. However, since the post-annealing treatment needs to reheat the crystal to the corresponding annealing temperature, the crystal needs to undergo multiple temperature rises and falls. Under the influence of multiple thermal shocks, the crystal is prone to cracking, which seriously limits the quality of the crystal.

[0004] Therefore, how to optimize the post-annealing process, eliminate the thermal stress in the large-size fluoride crystal, and thereby improve the quality and yield of the fluoride crystal has become a key technical problem to be solved in the field of fluoride crystal growth. SUMMARY

[0005] In view of the above problems existing in the prior art, the present application aims to provide an in-situ annealing device, an in-situ annealing control method and operation steps, so as to reduce the number of temperature rises and falls of the crystal, reduce the thermal stress generated during the crystal growth, thereby reducing the crystal defects and even cracking caused by stress concentration, and improving the utilization rate and internal quality of the crystal.

[0006] To achieve the above-mentioned application purposes, the first aspect of the present application provides an in-situ annealing device, which is used in combination with a growth device. The growth device includes a hollow furnace body, a heat field with an open cavity, a crucible and a seed rod. The heat field is accommodated in the hollow furnace body for providing a gradient heat source in the growth direction. The crucible is accommodated in the open cavity of the heat field. The seed rod is used to provide a cold source. The seed rod is connected with the crucible to make the crucible move along the growth direction to realize crystal growth.

[0007] The in-situ annealing device comprises a base and a lifting part, the base is arranged in the open cavity for selectively supporting the crucible, the lifting part is used to drive the base to move along the growth direction, the seed rod is detachably connected with the crucible, and the inner wall of the thermal field is provided with a protruding part for abutting against the base to form an annealing space, wherein

[0008] When the growth device is in the state of completing crystal growth, the lifting part controls the base to move against the direction of crystal growth so as to separate the crucible from the seed rod until the base contacts with the protruding part to form an annealing space for completing annealing.

[0009] Optionally, in some embodiments of the present application, a universal hole is arranged on the base for the seed rod to pass through,

[0010] When the growth device is in the state of completing crystal growth, the lifting part controls the base to move against the direction of crystal growth so as to separate the crucible from the seed rod until the base contacts with the protruding part to form an annealing space for completing annealing.

[0011] Optionally, in some embodiments of the present application, a crucible temperature sensor is arranged on the base, the crucible temperature sensor is used to sense the temperature of the crucible, the lifting part comprises a controller, and the controller is connected with the crucible temperature sensor and each gradient heat source of the thermal field, wherein

[0012] The thermal field is each gradient independently adjustable heat source, the controller adjusts the power of each gradient heat source of the thermal field based on the temperature of the crucible, so as to ensure that the temperature of the crucible remains constant before entering the annealing space.

[0013] Optionally, in some embodiments of the present application, the lifting part further comprises a lifting rod, and the controller is connected with the lifting rod for controlling the lifting rod to move along the growth direction, wherein

[0014] The controller adjusts the moving speed of the base based on the power change value of each gradient heat source of the thermal field, so that the lifting speed of the base matches the power change value of each gradient heat source of the thermal field to ensure that the temperature of the crucible remains constant before entering the annealing space.

[0015] Optionally, in some embodiments of the present application, a gravity sensor is further included, the gravity sensor is connected with the lifting rod for sensing the gravity change of the base, and the gravity sensor is connected with the controller to enable the controller to adjust the moving speed of the base based on the signal of the gravity sensor.

[0016] Optionally, in some embodiments of the present application, the base comprises a bottom plate, a connecting rod and a support, one end of the connecting rod is fixedly connected with the support rod, the other end is fixedly connected with the bottom plate, the bottom plate is used to connect with the lifting part, and the support is used to selectively support the crucible.

[0017] Optionally, in some embodiments of the present application, the crystal growth direction is the up-down direction, the crucible is sleeved in the seed rod to realize the detachable connection between the crucible and the seed rod,

[0018] When the growth device is in the crystal growth state, the base is not in contact with the crucible, the seed rod drives the crucible to move downward to realize crystal growth;

[0019] When the growth device is in the completed crystal growth state, the lifting part drives the base to move upward to make the support in contact with the crucible, and the crucible is separated from the seed rod until the bottom plate is in contact with the convex part to form a sealed space, and the base completes the movement.

[0020] In a second aspect of the present application, a control method for in-situ annealing is provided, which is used for the in-situ annealing device, and the control method comprises the following steps:

[0021] determining whether the growth device is in the completed crystal growth state, the crystal growth state is obtained based on the position of the crucible or the state of the crystal to be grown in the crucible;

[0022] controlling the lifting part to drive the base to move in the direction opposite to the crystal growth direction;

[0023] keeping the temperature of the crucible unchanged, which comprises adjusting the power of each gradient heat source of the thermal field or adjusting the movement speed of the base;

[0024] determining whether the base is in contact with the convex part, and adjusting the temperature of each gradient heat source of the thermal field to the annealing temperature.

[0025] Optionally, in some embodiments of the present application, adjusting the movement speed of the base comprises the following steps,

[0026] adjusting the movement speed of the base based on the change of the power of each gradient heat source;

[0027] and / or adjusting the movement speed of the base based on the change of the gravity of the base.

[0028] In a third aspect of the present application, an operation step for in-situ annealing is provided, which is realized based on the in-situ annealing device, and the operation step comprises the following steps:

[0029] 1) After the crucible is lowered, the in-situ annealing device is slowly raised from the initial position at the bottom of the hot zone, while the heating power of each gradient heat source is lowered to ensure that the temperature of the crucible remains unchanged;

[0030] 2) The in-situ annealing device is judged whether it is in contact with the crucible through the gravity sensing device in the in-situ annealing device, the base is controlled to be in contact with the protruding part to form a closed annealing space, and the rising is stopped;

[0031] 3) The heating power of each gradient heat source is lowered to the annealing temperature, and the annealing atmosphere is introduced into the annealing space;

[0032] 4) After constant temperature for 40-100 hours, the heating power of each gradient heat source is lowered to room temperature at a speed of 5-10℃ / h. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0034] Figure 1 is a structure schematic diagram of an in-situ annealing device and a growth device provided by the present application;

[0035] Figure 2 is a control method of in-situ annealing provided by the present application;

[0036] Figure 3 is an operation step of in-situ annealing provided by the present application.

[0037] Reference signs:

[0038] 100, growth device; 110, furnace body; 120, hot zone; 121, open cavity; 122, protruding part; 130, crucible; 140, seed rod;

[0039] 200, in-situ annealing device; 210, base; 211, bottom plate; 212, connecting rod; 213, support; 220, lifting part; 221, lifting rod. DETAILED DESCRIPTION

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a 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 efforts belong to the scope of protection of the present application. In addition, it should be understood that the specific implementation manners described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the orientation words such as "upper", "lower", "left", "right", "front", and "rear" usually refer to the upper, lower, left, and right in the actual use or working state of the device, specifically the drawing direction in the accompanying drawings.

[0041] It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments of the present application. And in the following embodiments, each embodiment has its own emphasis. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0042] It should be noted that for the crystal growth by the Bridgman method, the core idea is mainly to make the crucible pass through heat sources with different gradients. When passing through the heating area, the materials in the crucible are melted. When the crucible continues to descend, the temperature at the bottom of the crucible first drops below the melting point and starts to crystallize, and the crystal continues to grow as the crucible descends. This method is commonly used to prepare single crystals of alkali metal and alkaline earth metal halides and fluorides. Therefore, in the description of the present application, the "growth direction" is the specific direction of crystal growth and crystallization, usually the downward direction, and the "growth direction" is the direction where the crystal grows, usually the up and down direction. However, for the "growth direction" and the "growth direction", there are many possible directions, and the present application does not limit this, as long as the crystal can grow.

[0043] Please refer to Figure 1 , in the figure, an in-situ annealing device 200 is shown, which is used in conjunction with a growth device 100. The growth device 100 includes a hollow furnace body 110, a thermal field 120, a crucible 130, and a seed crystal rod 140.

[0044] ​​

[0045] The in-situ annealing device 200 comprises a fixedly connected lifting part 220 and a base part 210, the lifting part 220 comprises a lifting rod 221, a controller (not shown in the figure) and a lifting motor (not shown in the figure). The lifting motor is fixedly connected with the lifting rod 221 and the controller, and is used to drive the lifting rod 221 to move in the growth direction, generally the up-down direction. The lifting rod 221 is fixedly connected with the base part 210, and is used to drive the base part 210 to move in the growth direction. The controller is used to control the lifting speed of the lifting motor, so that the movement of the base part 210 in the growth direction better meets the demand, which will be further described below.

[0046] The base part 210 comprises a bottom plate 211, a connecting rod 212 and a support 213, and is accommodated in the open cavity 121 of the thermal field 120. The connecting rod 212 is used to connect the bottom plate 211 and the support 213. The bottom plate 211 is used to be fixedly connected with the lifting rod 221, and can be sealingly connected with the inner wall of the cavity of the thermal field 120. The bottom plate 211 is sealingly connected with the inner wall of the cavity of the thermal field 120. The support rod is used to selectively support the crucible 130, and the structure of the support rod matches the outer shape structure of the crucible 130 to better realize the support of the crucible 130.

[0047] Specifically, the open area of the open cavity 121 of the thermal field 120 is arranged below, the base part 210 is arranged in the open cavity 121 of the thermal field 120, the bottom plate 211 is fixedly connected with the support 213 through the connecting rod 212 in the axial direction above, the bottom plate 211 is connected with the lifting motor through the lifting rod 221 below, and the bottom plate 211 is sealingly connected with the inner wall of the thermal field 120 in the radial direction. That is, the support 213, the connecting rod 212, the bottom plate 211 and the lifting rod 221 are arranged in the crystal growth direction in turn.

[0048] The inner wall of the thermal field 120 is further provided with a protruding piece 122, which is used to limit the movement of the bottom plate 211 and is sealingly connected with the bottom plate 211 to form an annealing space. When the crystal is completed, the crucible 130 is lower than the position of the protruding piece 122 at the corresponding lowest point of the thermal field 120.

[0049] When the crystal is in the growth state, that is, the growth device 100 is in the state of completing the crystal growth, the in-situ annealing device 200 is below the open cavity 121 of the thermal field 120 and always does not contact the crucible 130. The gradient heat source of the thermal field 120 gradually decreases from top to bottom, and the crucible 130 slowly moves downward (moves in the growth direction of the crystal) under the driving of the seed rod, so that the to-be-produced crystal grows and continuously grows as the crucible 130 descends. When the crystal is completed, the crucible 130 is lower than the position of the protruding piece 122 at the corresponding lowest point of the thermal field 120.

[0050] When the crystal is in the completed growth state, i.e., the growth device 100 is in the completed crystal growth state, the controller controls the lifting motor to drive the lifting rod 221 and the base 210 to move upward, so that the support 213 is in contact with the crucible 130, and then the crucible 130 is separated from the support rod, and the crucible 130 is driven by the in-situ annealing device 200 to move upward until the bottom plate 211 is in contact with the convex part 122 to form an annealing space, and the in-situ annealing device 200 stops the movement of the crucible 130 in the crystal growth direction, at this time, the crucible 130 is in the annealing space, and the annealing of the grown crystal is completed.

[0051] Therefore, by providing the in-situ annealing space, the problem of poor quality of the grown crystal caused by multiple thermal shocks can be well solved. Through the scheme of the present application, the grown crystal can be directly annealed without taking the crucible 130 out of the growth furnace, which can effectively avoid the quality problem caused by multiple thermal shocks and improve the production quality.

[0052] It should be noted that the detachable connection mode of the crucible 130 and the seed rod can only ensure that the crucible 130 is separated from the seed rod when the support rod moves in the growth direction, and the specific connection mode is not limited.

[0053] In a specific embodiment, the crucible 130 is sleeved in the seed rod, i.e., the size of the bottom of the crucible 130 and the connecting section of the seed rod is smaller than the opening size of the seed rod, so that the crucible 130 is sleeved in the seed rod to realize detachable connection. As a further preferred mode, the connection shape of the crucible 130 and the seed rod is a special shape or a hexagonal structure, which can further strengthen the connection strength of the crucible 130 and the seed rod.

[0054] In an alternative embodiment, the crucible 130 and the seed rod are bolted, at this time, when the support 213 is in contact with the crucible 130, an unlocking device is provided on the support 213 to release the locked state of the crucible 130 and the seed rod. The contact device has various conventional technical means, and details are not described herein.

[0055] It should be further noted that the sealing connection of the bottom plate 211 and the inner wall of the hot field 120 is a preferred mode of the present application, but not an essential mode, as long as the bottom plate 211 and the convex part are sealingly connected to form an annealing space. In actual operation, in order to better form the annealing space and ensure the sealing of the annealing space, the bottom plate 211 and the inner wall of the hot field are preferably sealingly connected to improve the sealing protection of the annealing space.

[0056] It should be further noted that for the lifting motor and the controller, they are common technical means in the prior art, and there are various schemes, and the present application does not limit this. For the gradient heat source of the thermal field, it can be formed by combining multiple independent heat sources to form a thermal field with a gradient heat source, or the thermal field itself can be a thermal field with a gradient heat source, and the present application does not limit this.

[0057] Please continue to refer to Figure 1 In some specific embodiments, the in-situ annealing device 200 further comprises an atmosphere adjusting device (not shown in the figure), which is used to adjust the atmosphere in the annealing space, preferably CF4 and Ar, to achieve better annealing effect.

[0058] Further, the atmosphere adjusting device is connected with the controller, and the controller adjusts the atmosphere state in the annealing space through the atmosphere adjusting device based on different growing crystals, for example, for a 300mm CaF2 crystal, the atmosphere in the annealing space is adjusted to 60% CF4 and 40% Ar; for a 380mm CaF2 crystal, the atmosphere in the annealing space is adjusted to 70% CF4 and 30% Ar.

[0059] Please continue to refer to Figure 1 The bottom plate 211 of the base 210 is provided with a through hole for the seed rod to pass through, and the seed rod is sealingly connected with the bottom plate 211. By providing the through hole on the bottom plate 211, the structure of the in-situ annealing device 200 and the growing device 100 can be well matched to better form the annealing space.

[0060] Please continue to refer to Figure 1 The bottom plate 211 is also provided with a crucible temperature sensor, which is used to receive the temperature value of the crucible. The structure of the crucible temperature sensor is a prior art, and will not be described in detail.

[0061] Further, the controller is connected with the crucible temperature sensor and the thermal field gradient heat source, and the controller controls the change power of the thermal field 120 gradient heat source and the lifting speed of the bottom plate 211 based on the crucible temperature sensor to ensure that the temperature of the crucible 130 is unchanged.

[0062] Please continue to refer to Figure 1 The lifting rod 221 is also provided with a gravity sensor, which is used to receive the gravity value of the bottom plate 211, and is used to judge whether the support 213 has realized the support of the crucible 130. The structure of the gravity sensor is a prior art, and will not be described in detail.

[0063] Further, the controller is connected with the gravity sensor, and the controller further adjusts the movement speed of the bottom plate 211 based on the transmitted value of the gravity sensor to ensure that the temperature of the crucible 130 is unchanged.

[0064] Please refer toFigure 2 The application also provides a control method for the in-situ annealing device 200, the control method comprising:

[0065] S100: judging whether the growth device 100 is in a completed crystal growth state, the crystal growth state being based on the position of the crucible 130 or the state of the to-be-grown crystal in the crucible 130.

[0066] S200: controlling the lifting part 220 to drive the base 210 to move backward along the direction of crystal growth.

[0067] S300: keeping the temperature of the crucible 130 unchanged, comprising adjusting the power of each gradient heat source of the thermal field 120 and / or adjusting the moving speed of the base 210.

[0068] S400: judging whether the base 210 is in contact with the convex part 122, and adjusting the temperature of each gradient heat source of the thermal field 120 to an annealing temperature.

[0069] Please refer to Figure 3 The application also provides an operation step of in-situ annealing, which is implemented based on the in-situ annealing device 200, and the operation step comprises:

[0070] Step one: after the descending of the crucible 130 is completed, the in-situ annealing device 200 is controlled to slowly rise from the initial position at the bottom of the thermal field 120, and the heating power of each gradient heat source is lowered to keep the temperature of the crucible 130 unchanged.

[0071] Step two: judging whether the in-situ annealing device 200 is in contact with the crucible 130 through the gravity sensing device in the in-situ annealing device 200, controlling the base 210 to be in contact with the convex part 122 to form a closed annealing space, and stopping rising.

[0072] Step three: lowering the heating power of each gradient heat source to an annealing temperature, and introducing an annealing atmosphere into the annealing space.

[0073] Step four: after constant temperature for 40-100 hours, the heating power of each gradient heat source is lowered to room temperature at a speed of 5-10 ℃ / h.

[0074] A CaF2 crystal with a growth diameter of 300 mm obtained by the descending method of the crucible 130 is subjected to in-situ annealing by using the growth device 100:

[0075] After the end of the crucible 130 descent, the support 213 of the in-situ annealing device 200 is slowly raised from the bottom of the open cavity 121 at a speed of 150 mm / h, while the heating power is adjusted to decrease at a speed of 5°C / h, after rising 400 mm, the heating power is adjusted to decrease at a speed of 10°C / h, the rising speed is unchanged, and the crucible temperature detected by the crucible temperature sensor is kept unchanged.

[0076] After the support 213 rises 500 mm, the rising of the support 213 is adjusted from automatic to manual, and whether the support mechanism contacts the crucible is judged by the gravity sensing device placed in the lifting device of the crucible support mechanism; when the two are in contact, the rising mode of the support 213 is changed from manual to automatic, the speed is 50 mm / h, the heating power of the gradient heat source of the hot field 120 is adjusted by the controller to decrease at a speed of 30°C / h, and the crucible temperature detected by the crucible temperature sensor is kept unchanged.

[0077] When the bottom plate 211 contacts the convex part 122, the rising is stopped, at this time, the crucible 130 has completely entered the high temperature zone and formed an in-situ annealing annealing space with small temperature gradient; after the temperature of each temperature detection position in the high temperature zone is kept constant for 3 h, it is decreased to the annealing temperature 950°C at a speed of 30°C / h; a fluorinated atmosphere is introduced, the specific composition is CF4 and Ar, and the content of CF4 is 60%; after constant temperature for 48 hours, it is decreased to room temperature at a speed of 10°C / h.

[0078] A CaF2 crystal with a diameter of 380 mm is grown by the crucible descending method for in-situ annealing:

[0079] After the end of the crucible 130 descent, the support 213 of the in-situ annealing device 200 is slowly raised from the bottom of the open cavity 121 at a speed of 150 mm / h, while the heating power is adjusted to decrease at a speed of 5°C / h, after rising 400 mm, the heating power is adjusted to decrease at a speed of 10°C / h, the rising speed is unchanged, and the crucible temperature detected by the crucible temperature sensor is kept unchanged.

[0080] After the support 213 rises 500 mm, the rising of the support 213 is adjusted from automatic to manual, and whether the support mechanism contacts the crucible is judged by the gravity sensing device placed in the lifting device of the crucible support mechanism; when the two are in contact, the rising mode of the support 213 is changed from manual to automatic, the speed is 50 mm / h, the heating power of the gradient heat source of the hot field 120 is adjusted by the controller to decrease at a speed of 30°C / h, and the crucible temperature detected by the crucible temperature sensor is kept unchanged.

[0081] When the bottom plate 211 contacts the convex piece 122, the rising is stopped, at this time, the crucible has completely entered the high temperature zone and formed the annealing space with small temperature gradient which can be annealed in situ; after the temperature of each temperature detection position in the high temperature zone is stable for 5h, the temperature is decreased to the annealing temperature 950℃ at the speed of 20℃ / h; the fluorinated atmosphere is input, the specific composition is CF4 and Ar, the content of CF4 is 70%; after the constant temperature for 60h, the temperature is decreased to room temperature at the speed of 10℃ / h.

[0082] The above detailed the scheme of the present application, the principle and implementation of the present application are described by applying specific examples; the above example is only used to help understand the method of the present application and its core idea; at the same time, for the general technical personnel in the art, according to the idea of the present application, the specific implementation and application range will be changed; according to the above, the content of the specification should not be understood as the limitation of the present application.

[0083] The phrase "one embodiment", "an embodiment", or "some embodiments" as used throughout this specification, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application, and is not necessarily included in all embodiments. Thus, the various appearances of the phrases "in one embodiment", "in an embodiment", or "in some embodiments" in various places throughout this specification are not necessarily referring to the same embodiment of the present application. Furthermore, the particular features, structures, or characteristics can be combined in any suitable manner in one or more embodiments without necessarily being included in all embodiments. It is understood that other variations and modifications of the applications described and illustrated herein can be made based on the teachings herein, and that the present application is not limited to the particular embodiments described and illustrated.

Claims

1. An in-situ annealing device for use with a growth device, the growth device comprising a hollow furnace body, a hot field provided with an open cavity, a crucible and a seed rod, the hot field being housed in the hollow furnace body for providing a gradient heat source in a growth direction, the crucible being housed in the open cavity of the hot field, the seed rod being used for providing a cold source, the seed rod being connected with the crucible for moving the crucible along the growth direction to realize crystal growth, characterized in that, the in-situ annealing device comprises a base and a lifting part connected with each other, the base being housed in the open cavity for selectively supporting the crucible, the lifting part being used for moving the base along the growth direction, the seed rod being detachably connected with the crucible, a protrusion being provided on an inner wall of the hot field for abutting against the base to form an annealing space, wherein when the growth device is in a state of completing crystal growth, the lifting part controls the base to move against the direction of the crystal growth to make the crucible disengage from the seed rod until the base contacts with the protrusion to form the annealing space for completing annealing.

2. The base is provided with a through hole for the seed rod to pass through.

3. When the growth device is in a state of crystal growth, the base does not contact with the crucible, the seed rod passes through the base and is detachably connected with the crucible, and the seed rod moves the crucible along the direction of crystal growth to realize crystal growth.

2. The in-situ anneal apparatus of claim 1, wherein, 4. The in-situ annealing device further comprises a crucible temperature sensor provided on the base, the crucible temperature sensor being used for sensing the temperature of the crucible, the lifting part comprises a controller, the controller being connected with the crucible temperature sensor and each gradient heat source of the hot field, wherein the hot field is each gradient independently adjustable heat source, the controller adjusts the power of each gradient heat source of the hot field based on the temperature of the crucible for ensuring that the temperature of the crucible remains constant before entering the annealing space.

5. The lifting part further comprises a lifting rod, the controller is connected with the lifting rod for controlling the lifting rod to move along the growth direction, wherein the controller adjusts the moving speed of the base based on the change value of the power of each gradient heat source of the hot field, so that the lifting speed of the base matches the change value of the power of each gradient heat source of the hot field to ensure that the temperature of the crucible remains constant before entering the annealing space.

3. The in-situ anneal apparatus of claim 1, wherein, 6. The in-situ annealing device further comprises a gravity sensor, the gravity sensor is connected with the lifting rod for sensing the gravity change of the base, and is connected with the controller for making the controller adjust the moving speed of the base based on the signal of the gravity sensor.

7. The base comprises a bottom plate, a connecting rod and a support, one end of the connecting rod is fixedly connected with the support, the other end of the connecting rod is fixedly connected with the bottom plate, the bottom plate is used for connecting with the lifting part, and the support is used for selectively supporting the crucible.

4. The in-situ anneal apparatus of claim 3, wherein, 8. The direction of crystal growth is upward and downward direction, the crucible is sleeved in the seed rod to realize the detachable connection between the crucible and the seed rod.

9. When the growth device is in a state of crystal growth, the base does not contact with the crucible, the seed rod moves the crucible downward to realize crystal growth.

5. The in-situ anneal apparatus of claim 4, wherein, ​ 6. An in-situ anneal apparatus as claimed in any one of claims 1-5, wherein, ​ 7. The in-situ anneal apparatus of claim 6, wherein, ​ ​ When the growth device is in the state of completing crystal growth, the lifting part drives the base to move upward to make the support contact with the crucible and make the crucible separate from the seed rod until the bottom plate contacts with the convex part to form a closed space, and the base completes the movement.

8. A method of controlling in-situ annealing for the in-situ annealing apparatus according to any one of claims 1 to 7, characterized by, The control method comprises: judging whether the growth device is in the state of completing crystal growth, the state of crystal growth is based on the position of the crucible or the state of the crystal to be grown in the crucible; controlling the lifting part to drive the base to move backward along the direction of crystal growth; keeping the temperature of the crucible unchanged, including adjusting the power of each gradient heat source of the thermal field and / or adjusting the movement speed of the base; judging whether the base contacts with the convex part, and adjusting the temperature of each gradient heat source of the thermal field to the annealing temperature.

9. The method of claim 8, wherein the in-situ anneal is controlled by: adjusting the movement speed of the base, including the steps of, adjusting the movement speed of the base based on the change of the power of each gradient heat source; and / or adjusting the movement speed of the base based on the change of the gravity of the base.

10. A method of in-situ annealing, implemented by means of an in-situ annealing apparatus according to any one of claims 1-7, characterized by, The operation steps comprise: 1) after the crucible is lowered, the in-situ annealing device is controlled to slowly rise from the initial position at the bottom of the thermal field, and the heating power of each gradient heat source is lowered to keep the temperature of the crucible unchanged; 2) judging whether the in-situ annealing device contacts with the crucible through the gravity sensing device in the in-situ annealing device, controlling the base to contact with the convex part to form a closed annealing space, and stopping rising; 3) lowering the heating power of each gradient heat source to the annealing temperature, and introducing annealing atmosphere into the annealing space; 4) after constant temperature for 40-100 hours, lowering the heating power of each gradient heat source to room temperature at the speed of 5-10 ℃ / h.

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