Silicon carbide single crystal growth device
By setting up liftable connecting rods and heating mechanisms on the crucible cover of the silicon carbide single crystal growth device, the heat conduction path is optimized, and the heat dissipation and temperature unevenness problems at the bottom of the crucible are solved, energy saving and consumption reduction and high-quality carbonization are achieved Silicon single crystal growth.
Patent Information
- Application Number
- CN201910328574.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2019-04-23
- Publication Date
- 2024-12-06
- Estimated Expiration
- 2039-04-23
AI Technical Summary
The existing silicon carbide single crystal growth device is heat dissipated due to the heat conduction of the crucible bracket, making it difficult to achieve uniformity of the bottom temperature of the graphite crucible, affecting the growth quality of the silicon carbide single crystal, and requiring increased heating power, resulting in waste of energy.
A single crystal growth device of silicon carbide is designed. By setting up a liftable connecting rod and heating mechanism on the crucible cover, the heat conduction path is optimized, so that heat is transmitted upward only through the crucible cover, achieving a temperature field of lower and lower height, and The temperature is adjusted by refrigerant and process gas.
It effectively avoids heat dissipation, saves energy and reduces consumption, improves the growth quality of silicon carbide single crystals, achieves uniformity of the temperature field and efficient growth of silicon carbide single crystals.
Smart Images
Figure CN109913951B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a silicon carbide single crystal growth device. Background Art
[0002] The physical vapor transport method (PVT method) has become the main technical method for growing silicon carbide single crystals. This method is to place silicon carbide polycrystalline raw materials at the bottom of the graphite crucible body, cover the graphite crucible body with a graphite crucible cover to form a closed space, and install silicon carbide seed crystals on the lower surface of the graphite crucible cover. By heating the system composed of the graphite crucible body and the graphite crucible cover, the silicon carbide polycrystalline raw materials in the graphite crucible body are sublimated, and a suitable temperature gradient is maintained between the silicon carbide polycrystalline raw materials and the silicon carbide seed crystals. The sublimated silicon carbide particles will be deposited and grown on the silicon carbide seed crystals, thereby obtaining silicon carbide single crystals. This technical method requires that the temperature at the bottom of the graphite crucible body be higher than the temperature of the crucible cover on the upper part of the graphite crucible body, so as to obtain a temperature field with high bottom and low top to meet the needs of silicon carbide single crystal growth.
[0003] The existing crucibles used for growing silicon carbide single crystals generally mount the graphite crucible body on the crucible support rod. In this way, the heat at the bottom of the graphite crucible will be dissipated due to the heat conduction of the crucible support rod. To maintain the process temperature at the bottom of the graphite crucible, the heating power must be increased, which wastes energy. More importantly, it is difficult to achieve uniform temperature at the bottom of the graphite crucible, which affects the growth of silicon carbide single crystals. Summary of the invention
[0004] The purpose of the present invention is to provide a silicon carbide single crystal growth device, which optimizes the heat conduction path of a graphite crucible, makes it easy to obtain a temperature field with high bottom and low top in the graphite crucible, is beneficial to the growth of silicon carbide single crystals, saves energy and reduces consumption, and improves the growth quality of silicon carbide single crystals.
[0005] In order to achieve the above object, the technical solution adopted by the present invention is:
[0006] A silicon carbide single crystal growth device comprises a working chamber, a lifting and lowering connecting rod passing through the working chamber, a first driving mechanism for driving the lifting and lowering of the connecting rod, a crucible arranged in the working chamber, and a heating mechanism for heating the crucible;
[0007] The crucible comprises a crucible cover fixed to the bottom of the connecting rod, and a crucible body detachably connected to the bottom of the crucible cover;
[0008] The connecting rod comprises a rod body, a first channel provided on the rod body for introducing and discharging a refrigerant, and a second channel provided on the rod body for introducing a process gas; the first channel and the second channel are isolated from each other, and the second channel is connected to the working chamber; the connecting rod is used to cool the crucible cover by the refrigerant and / or the process gas;
[0009] The working cavity also includes an air outlet.
[0010] Preferably, the first channel is an annular cavity, and an inlet and an outlet are provided at the upper end of the annular cavity.
[0011] More preferably, the second channel is a cylindrical cavity, and a process air hole communicating with the working cavity is opened on the bottom side of the cylindrical cavity.
[0012] More preferably, the connecting rod, the annular cavity and the cylindrical cavity all extend coaxially.
[0013] More preferably, there are a plurality of process air holes, and the plurality of process air holes are evenly spaced and arranged around the circumference.
[0014] More preferably, the crucible cover is arranged at the bottom end of the cylindrical cavity, and the device further comprises an infrared thermometer for measuring the temperature of the crucible cover along the axial direction of the cylindrical cavity.
[0015] Preferably, the connecting rod is rotatable around its own axial center line and is inserted into the working cavity. The device also includes a second driving mechanism for driving the connecting rod to rotate.
[0016] Preferably, the heating mechanism comprises a heating cylinder arranged around the outer periphery of the crucible, and a heat-insulating cover sleeved around the outer periphery of the heating cylinder and opening upward, and the heating temperature of the heating cylinder gradually increases from top to bottom.
[0017] More preferably, the heating cylinder extends coaxially with the crucible.
[0018] Preferably, the connecting rod and the crucible cover are heat-conducting to each other, and the crucible cover and the crucible body are heat-insulated from each other.
[0019] Due to the application of the above technical scheme, the present invention has the following advantages compared with the prior art: a silicon carbide single crystal growth device of the present invention, by arranging the connecting rod on the crucible cover, not only avoids the problems caused by arranging the connecting rod on the crucible body, such as easy dissipation of heat at the bottom of the crucible body, increased energy consumption caused by the need to increase the heating power to maintain the process temperature at the bottom of the crucible, difficulty in achieving uniformity of the temperature at the bottom of the crucible body, and affecting the growth quality of the silicon carbide single crystal; at the same time, it also improves the direction of heat transfer of the crucible, optimizes the heat conduction path of the crucible, so that heat can only be transmitted upward through the crucible cover, and it is easier to achieve the temperature field requirement of high at the bottom and low at the top, thereby saving energy and reducing consumption, and improving the growth quality of the silicon carbide single crystal. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Attached Figure 1 It is a schematic diagram of the structure of the device of the present invention.
[0021] Wherein: 1. working chamber; 2. connecting rod; 21. rod body; 22. first channel; 23. second channel; 3. first driving mechanism; 4. crucible; 41. crucible cover; 42. crucible body; 5. heating mechanism; 51. heating cylinder; 52. heat preservation cover; 6. air outlet; 7. feed port; 8. discharge port; 9. process air hole; 10. infrared thermometer; 11. second driving mechanism; 12. cover plate; 13. silicon carbide seed crystal; 14. silicon carbide polycrystalline raw material. DETAILED DESCRIPTION
[0022] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.
[0023] See also Figure 1 As shown, the above-mentioned silicon carbide single crystal growth device includes a working chamber 1, a connecting rod 2 that can be raised and lowered and penetrated in the working chamber 1, a first driving mechanism 3 for driving the connecting rod 2 to be raised and lowered, a crucible 4 arranged in the working chamber 1, and a heating mechanism 5 for heating the crucible 4. A cover plate 12 is provided on the upper part of the working chamber 1. When it is necessary to load raw materials or take out finished products, the cover plate 12 is opened, and the crucible 4 is lifted upward out of the working chamber 1. In this embodiment, the heating mechanism 5 includes a heating cylinder 51 arranged around the outer periphery of the crucible 4, and a heat-insulating cover 52 that is sleeved on the outer periphery of the heating cylinder 51 and opens upward. The heating temperature of the heating cylinder 51 gradually increases from top to bottom to provide a temperature field with a high bottom and a low top for the growth of silicon carbide single crystals. The heating cylinder 51 extends coaxially with the crucible 4, and its axis is parallel to the vertical direction. There is a gap between the inner periphery of the heating cylinder 51 and the outer periphery of the crucible 4, and the outer periphery of the heating cylinder 51 is attached to the inner periphery of the heat-insulating cover 52. The heating cylinder 51 can be heated by resistance or induction.
[0024] The crucible 4 includes a crucible cover 41 fixed to the bottom of the connecting rod 2, and a crucible body 42 detachably connected to the bottom of the crucible cover 41. In this embodiment, the connecting rod 2 and the crucible cover 41 are mutually heat-conducting, and the crucible cover 41 and the crucible body 42 are mutually heat-insulated. Through this arrangement, the connecting rod 2 conducts heat to the crucible cover 41, improves the heat transfer direction of the crucible 4, optimizes the heat conduction path of the crucible 4, and makes the heat only transfer upward through the crucible cover 41, making it easier to achieve the temperature field requirement of high at the bottom and low at the top, saving energy and reducing consumption, and improving the growth quality of silicon carbide single crystals.
[0025] The connecting rod 2 includes a rod body 21, a first channel 22 for passing a refrigerant through the rod body 21, and a second channel 23 for passing a process gas through the rod body 21; the first channel 22 and the second channel 23 are separated from each other, and the second channel 23 is connected to the working chamber 1. The connecting rod 2 is used to cool the crucible cover 41 by means of a refrigerant and / or a process gas. In this embodiment, the refrigerant is liquid cooling water, and the process gas is argon gas, which is used to adjust the pressure and promote the growth of silicon carbide single crystals. In order to maintain the fluidity of the gas, the working chamber 1 also includes an outlet 6 for passing the process gas.
[0026] In this embodiment, the first channel 22 is an annular cavity, and the upper end of the annular cavity is provided with a feed port 7 and a discharge port 8. The second channel 23 is a cylindrical cavity, and the bottom side of the cylindrical cavity is provided with a process air hole 9 connected to the working cavity 1. The connecting rod 2, the annular cavity, and the cylindrical cavity all extend coaxially, and their axis lines are parallel to the vertical direction.
[0027] In this embodiment, there are multiple process air holes 9, and the multiple process air holes 9 are evenly spaced and arranged around the circumference. The connecting rod 2 includes a horizontal plate arranged at its lower end, the annular cavity is located above the horizontal plate, the cylindrical cavity passes through the horizontal plate, and the process air holes 9 are opened in the horizontal plate. Through this arrangement, the crucible cover 41 is exposed at the bottom end of the cylindrical cavity. The above-mentioned silicon carbide single crystal growth device also includes an infrared thermometer 10 for measuring the temperature of the crucible cover 41 along the axial direction of the cylindrical cavity. Through this structure, the real-time temperature of the crucible cover 41 can be measured more accurately, which is convenient for adjusting the temperature field.
[0028] The connecting rod 2 is rotatable around its own axis and is inserted into the working chamber 1 . The silicon carbide single crystal growth device further includes a second driving mechanism 11 for driving the connecting rod 2 to rotate.
[0029] As the silicon carbide single crystal grows, the growth point gradually decreases. Since the temperature field has highs at the top and lows at the bottom, the temperature corresponding to the growth point gradually increases. The temperature of the growth point is correspondingly lowered by lifting the crucible 4. During the growth process, the crucible 4 is kept rotating around its own axis to improve the temperature uniformity and the growth quality of the silicon carbide single crystal.
[0030] The working process of this embodiment is described in detail below:
[0031] Open the cover plate 12, lift the crucible 4 out of the working chamber 1, open the crucible 4, load the silicon carbide seed crystal 13 on the lower surface of the crucible cover 41, and load the silicon carbide polycrystalline raw material 14 into the crucible body 42; after the crucible 4 is loaded, lower it into the working chamber 1, and close the cover plate 12;
[0032] Control the heating cylinder 51 to start heating, monitor the temperature of the crucible cover 41 through the infrared thermometer 10, and introduce appropriate amounts of process gas and refrigerant as needed to keep the temperature measured by the infrared thermometer 10 at the required temperature;
[0033] During the growth of the silicon carbide single crystal, the crucible 4 is kept rotating to make the growth temperature in the crucible 4 more uniform; at the same time, the crucible 4 is lifted upward according to the growth speed of the silicon carbide single crystal to keep the height of the growth point unchanged.
[0034] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it. They cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.
Claims
1. A silicon carbide single crystal growth device, characterized in that: It comprises a working cavity, a lifting and lowering connecting rod passing through the working cavity, a first driving mechanism for driving the lifting and lowering of the connecting rod, a crucible arranged in the working cavity, and a heating mechanism for heating the crucible; The crucible comprises a crucible cover fixed to the bottom of the connecting rod, and a crucible body detachably connected to the bottom of the crucible cover; The connecting rod comprises a rod body, a first channel provided on the rod body for introducing and discharging a refrigerant, and a second channel provided on the rod body for introducing a process gas; the first channel and the second channel are isolated from each other, and the second channel is connected to the working chamber; the connecting rod is used to cool the crucible cover by the refrigerant and / or the process gas; The working cavity also includes an air outlet; The first channel is an annular cavity, and a feed inlet and a discharge outlet are provided at the upper end of the annular cavity; The second channel is a cylindrical cavity, and a process air hole communicating with the working cavity is opened on the bottom side of the cylindrical cavity; The connecting rod and the crucible cover are heat-conducting to each other, and the crucible cover and the crucible body are heat-insulated to each other.
2. A silicon carbide single crystal growth device according to claim 1, characterized in that: The connecting rod, the annular cavity and the cylindrical cavity all extend coaxially.
3. The silicon carbide single crystal growth device according to claim 1, characterized in that: There are a plurality of process air holes, and the plurality of process air holes are evenly spaced and arranged around the circumference.
4. The silicon carbide single crystal growth device according to claim 1, characterized in that: The crucible cover is arranged at the bottom end of the cylindrical cavity, and the device further comprises an infrared thermometer for measuring the temperature of the crucible cover along the axial direction of the cylindrical cavity.
5. The silicon carbide single crystal growth device according to claim 1, characterized in that: The connecting rod is rotatable around its own axis and is inserted into the working cavity. The device also includes a second driving mechanism for driving the connecting rod to rotate.
6. The silicon carbide single crystal growth device according to claim 1, characterized in that: The heating mechanism comprises a heating cylinder arranged around the outer periphery of the crucible, and a heat-insulating cover sleeved on the outer periphery of the heating cylinder and opening upward, and the heating temperature of the heating cylinder gradually increases from top to bottom.
7. The silicon carbide single crystal growth device according to claim 6, characterized in that: The heating cylinder extends coaxially with the crucible.