Vacuum device and detection device for monitoring contact position of seed crystal and melt

Abstract

The utility model relates to the technical field of silicon carbide crystal growth, in particular to a vacuum device and a detection device for monitoring the contact position of a seed crystal and a melt. The utility model provides a vacuum device which comprises a fixing device and an electrode binding post. The fixing device further comprises a flange upper cover, a metal window flange and a base. The utility model provides a detection device for monitoring the contact position of the seed crystal and the melt. The device comprises the vacuum device, a lead and a universal meter, according to the detection device, the contact condition of the seed crystal and the melt liquid level can be judged by observing the change of the universal display number. When the seed crystal is in contact with the liquid level of the melt, sudden change of the reading of the resistance value of the universal meter is triggered to judge the welding position of the seed crystal, so that the problem that the welding process of the seed crystal cannot be observed is solved, and the conditions that the seed crystal is not in contact with the liquid level of the melt and the seed crystal is excessively immersed below the liquid level of the melt can be avoided; the growth stability of the silicon carbide single crystal is improved, and the quality of the single crystal is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of silicon carbide crystal growth, in particular to a vacuum device and a detection device for monitoring the contact position between a seed crystal and a melt. Background Art

[0002] Choosing energy sources with less carbon dioxide emissions and promoting energy-saving measures are considered to be urgent tasks facing all countries today.

[0003] Silicon carbide (SiC) semiconductor material is a representative of the third generation of new wide bandgap semiconductor materials. Compared with the first generation semiconductor silicon, silicon carbide has about 3 times the bandgap width, 2 times the saturated electron drift rate, 3 times the thermal conductivity and 10 times the breakdown field strength. It also has high critical breakdown field strength, high thermal conductivity, high electron saturation drift rate, excellent mechanical properties and physical and chemical stability. It can be used to make high-voltage, high-temperature and other high-power devices. Therefore, silicon carbide semiconductor power devices are expected to be widely used in the industrial field, especially in high-power, high-voltage, high-temperature and strong radiation environments.

[0004] As a technology capable of growing high-quality silicon carbide single crystals, the liquid phase method still faces the problem of unobservable seed crystal fusion process. In the actual process, the contact position between the seed crystal and the melt is mostly obtained through empirical judgment and position calculation, but this often leads to the seed crystal failing to contact the melt surface and the seed crystal being too immersed below the melt surface. Therefore, accurate judgment of the seed crystal fusion position plays a vital role in the growth of high-quality silicon carbide single crystals by the liquid phase method. The ability to accurately judge the contact position between the seed crystal and the melt surface is also conducive to meniscus pulling, improving the growth rate of silicon carbide single crystals and the quality of the grown crystals.

[0005] The utility model provides a vacuum device and a detection device for monitoring the contact position between the seed crystal and the melt, which are used to monitor the contact situation between the seed crystal and the melt, so as to solve the problem in the prior art that the seed crystal welding process cannot be observed, resulting in the seed crystal failing to contact the melt surface, the seed crystal being immersed too much in the melt surface, etc., thereby affecting the crystal growth quality. Utility Model Content

[0006] The utility model aims to provide a vacuum device and a detection device for monitoring the contact position between a seed crystal and a melt, so as to solve the problems existing in the prior art that the seed crystal fails to contact the melt surface and the seed crystal is too immersed in the melt surface.

[0007] The technical solution provided by the utility model is: a vacuum device, comprising a fixing device and an electrode terminal; the electrode terminal penetrates through and is fixed on the fixing device.

[0008] Preferably, the fixing device comprises a flange cover, a metal window flange, and a base; a groove is provided on the base; a boss is provided in the middle of the electrode terminal; and the boss is correspondingly embedded in the groove.

[0009] Preferably, the upper and lower halves of the electrode terminal are respectively provided with a horizontal through hole, and the top and tail ends are provided with vertical threaded inner holes, and the horizontal through hole and the vertical threaded inner hole are perpendicular to each other and interpenetrate each other.

[0010] Preferably, the base and the flange upper cover are pressed and fixed to the electrode terminal by four studs in a vertical manner;

[0011] The metal window flange is buckled and placed on the base.

[0012] Preferably, the bottom of the boss, the bottom of the flange upper cover, and the bottom of the metal window flange are all provided with sealing rings;

[0013] The sealing ring is one of a rubber sealing ring, a polytetrafluoroethylene sealing ring, a polyurethane sealing ring, a composite sealing ring, a silicone sealing ring, and a fluororubber sealing ring.

[0014] Preferably, the base and the flange cover are both made of insulating materials; the insulating material is one of high temperature resistant materials such as polyimide, polyetheretherketone (PEEK), polytetrafluoroethylene, etc.

[0015] Preferably, the electrode terminal is made of a metal material that is a good conductor; the metal material that is a good conductor is one of copper, silver or alloy steel.

[0016] The utility model also provides a detection device: a detection device for monitoring the contact position between a seed crystal and a melt, comprising the above-mentioned vacuum device, a wire and a multimeter.

[0017] Preferably, one end of the wire passes through the horizontal through hole respectively; the fixing screw cooperates with the vertical threaded inner hole to press the wire tightly;

[0018] The two electrodes on the upper part of the two electrode terminals are respectively connected to the positive and negative electrodes of the multimeter through wires;

[0019] The two electrodes at the lower parts of the two electrode terminals are respectively connected to the devices to be detected through wires.

[0020] Preferably, the wire of the conductor is made of one of metal materials such as copper, aluminum, rhenium, tungsten, nickel or alloys thereof.

[0021] Compared with the prior art, the advantages of the utility model are:

[0022] (1) The utility model provides a vacuum device and a detection device for monitoring the contact position between the seed crystal and the melt. When the seed crystal contacts the melt surface, a sudden change in the resistance value of the multimeter is triggered, which is used to determine the position where the seed crystal is welded. This solves the problem that the seed crystal welding process cannot be observed, and can avoid the situation where the seed crystal fails to contact the melt surface or the seed crystal is immersed below the melt surface for too long.

[0023] (2) The utility model provides a detection device for monitoring the contact position between the seed crystal and the melt. The detection device is installed at a circular hole reserved on the shell of the silicon carbide liquid phase vacuum furnace, which will not change the structure of the vacuum furnace and can still provide a sealed environment for crystal growth. The lower parts of the two electrode terminals on the detection device are respectively connected to the carbon-based thermal field and the graphite seed crystal rod through wires. When the seed crystal contacts the liquid surface, the graphite seed crystal holder and the melt form a closed loop current, and the resistance value of the multimeter changes instantly. The deflection of the multimeter pointer can be observed to determine whether the seed crystal contacts the melt surface, and the fusion position of the seed crystal can be adjusted in time according to the needs of crystal growth. There is no need to set an observation window above the melt surface or open the silicon carbide liquid phase vacuum furnace to observe the fusion of the seed crystal during crystal growth. The crystal growth defects caused by atmosphere convection can be eliminated, the stability of crystal growth is greatly improved, and the quality of silicon carbide single crystals is improved.

[0024] (3) The utility model provides a vacuum device and a detection device for monitoring the contact position between the seed crystal and the melt, which can monitor the contact position between the seed crystal and the melt surface by changing the resistance value of a multimeter, which is beneficial to meniscus pulling, improving the growth rate of silicon carbide single crystals, reducing single crystal defects, and producing high-quality silicon carbide single crystals with the required orientation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0026] Figure 1 It is a three-dimensional diagram of the vacuum device described in the utility model;

[0027] Figure 2 It is a side view of the vacuum device described in the utility model;

[0028] Figure 3 A top view of the vacuum device described in the utility model;

[0029] Figure 4 It is a three-dimensional diagram of the metal window flange described in the utility model;

[0030] Figure 5 It is a top view of the metal window flange described in the utility model;

[0031] Figure 6 It is a side view of the metal window flange described in the utility model;

[0032] Figure 7 A three-dimensional diagram of the base described in the utility model;

[0033] Figure 8 A top view of the base of the utility model;

[0034] Fig. 9 It is a side view of the base described in the utility model;

[0035] Fig.10 It is a three-dimensional diagram of the flange upper cover described in the utility model;

[0036] Fig.11 It is a top view of the flange upper cover described in the utility model;

[0037] Fig.12 It is a side view of the flange upper cover described in the utility model;

[0038] Fig.13 This is a three-dimensional diagram of the electrode terminal described in the utility model;

[0039] Fig.14 It is a side view of the electrode terminal of the utility model;

[0040] Fig.15 A top view of the electrode terminal described in the utility model;

[0041] Fig.16 The detection device described in the utility model;

[0042] Fig.17 It is a connection diagram of the detection device described in the utility model with the carbon-based thermal field and the graphite seed crystal rod;

[0043] Among them: 1. Metal window flange; 2. Base; 21. Groove; 22. Step 3. Flange cover; 4. Wire; 5. Electrode wire column; 51. Horizontal through hole; 52. Boss; 53. Vertical threaded hole; 6. Fixing screw; 7. Graphite seed crystal rod; 8. Carbon-based thermal field; 9. Multimeter; 11. Fixing device. DETAILED DESCRIPTION

[0044] The following is a further detailed description of the present invention in conjunction with specific embodiments:

[0045] A vacuum device, such as Figure 1 , Figure 2 , Figure 3 As shown, it includes a fixing device 11 and an electrode terminal 5.

[0046] The fixing device 11 comprises: a flange cover 3, such as Fig.10 , Fig.11 , Fig.12 As shown; metal window flange 1, such as Figure 4 , Figure 5 , Figure 6 As shown; base 2. Among them, Figure 7 , Figure 8 , Fig. 9 As shown, the base 2 is of convex design, and a groove 21 is provided on the base 2; Fig.13 , Fig.14 , Fig.15 As shown, a ring-shaped boss 52 is provided in the middle of the electrode terminal 5 ; the groove 21 provided on the base 2 fits with the boss 52 provided in the middle of the electrode terminal 5 .

[0047] In other embodiments, the base 2 may be designed in other shapes such as flat or concave. The boss 52 provided in the middle of the electrode terminal 5 may be in other shapes such as square, diamond, triangle, etc., or may be other forms of protrusions with a fixing function, and the groove 21 provided on the base 2 fits with the boss 52 provided in the middle of the electrode terminal 5.

[0048] Place two metal electrode terminals 5 in the grooves 21 of the convex base 2 respectively, so that the boss 52 in the middle of the electrode terminals 5 corresponds to the groove 21 on the base 2; then buckle the flange cover on the two electrode terminals 5, at this time, the bottom surface of the flange cover 3 is in contact with the top surface of the convex base 2, and the boss 52 in the middle of the two electrode terminals 5 is completely wrapped, and the flange cover 3 and the convex base 2 are matched up and down by four studs to press and fix the electrode terminals 5; then buckle the metal window flange 1 on the step 22 of the base 2 to assemble into a vacuum device; the bottom of the boss 52 in the middle of the electrode 5 and the bottom of the flange cover 3 are provided with rubber rings for sealing the device.

[0049] In other embodiments, when the boss 52 in the middle of the electrode terminal 5 is interference-fitted with the groove 21 on the base 2, the flange cover may not be provided.

[0050] like Fig.13 , Fig.14 , Fig.15 As shown, the upper and lower halves of the electrode terminal 5 are respectively provided with a horizontal circular through hole 51, and the top and tail ends are respectively provided with a vertical threaded hole 53, and the horizontal circular through hole 51 and the vertical threaded hole 53 are perpendicular to each other and interpenetrate each other.

[0051] Pass one end of the two wires 4 through the two circular through holes 51 on the upper part of the two electrode terminals 5, and press the wires 4 by means of the fixing screws 6 and the vertical internal threaded holes 53 on the top of the electrode terminals 5; connect the other ends of the two wires 4 to the positive and negative poles of the multimeter 9, respectively; pass one end of the two wires 4 through the two circular through holes 51 on the lower part of the two electrode terminals 5, and press the wires 4 by means of the fixing screws 6 and the vertical threaded holes 53 on the bottom of the electrode terminals 5; assemble the detection device, such as Fig.16 shown.

[0052] In other embodiments, the horizontal through hole 51 may also be in other shapes such as a square or a diamond, and the size of the horizontal through hole 51 matches the thickness of the conductive wire 4 .

[0053] The other ends of the two wires 4 connected to the lower half of the electrode terminal 5 in the detection device are connected to the carbon-based thermal field 8 and the graphite seed crystal rod 7 respectively. Fig.17 As shown; finally, the detection device is installed in the circular groove reserved on the silicon carbide liquid phase vacuum furnace shell, that is, the vacuum device with the metal window flange is fixed in the circular groove of the furnace shell by six studs; a ring is provided at the bottom of the metal window flange 1, so that the whole device achieves a vacuum sealing effect.

[0054] The seed crystal is fixed on the graphite seed crystal holder. The graphite seed crystal holder and the graphite seed crystal rod are connected by threads. The melt is placed in a graphite crucible. The outer surface of the graphite crucible is wrapped with thermal insulation materials. After vacuuming and filling with protective gas, the seed crystal holder is lowered. When the seed crystal contacts the melt surface, the graphite seed crystal holder and the melt form a closed loop current. The resistance value of the multimeter changes instantly. The corresponding position at this time is the position where the seed crystal is welded, which is also the height position of the melt surface. As the seed crystal grows, the melt surface changes accordingly. The position of the seed crystal welding can be adjusted in time according to the needs of crystal growth.

[0055] The above embodiments are only for illustrating the technical concept and features of the utility model, and their purpose is to enable people familiar with this technology to understand the content of the utility model and implement it accordingly, and they cannot be used to limit the protection scope of the utility model. For those skilled in the art, it is obvious that the utility model is not limited to the details of the above exemplary embodiments, and the utility model can be implemented in other specific forms without departing from the spirit or basic features of the utility model. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the utility model is limited by the attached claims rather than the above description, so it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the utility model.

Claims

1. A vacuum device, characterized in that: It comprises a fixing device (11) and an electrode terminal (5); the electrode terminal (5) penetrates through and is fixed on the fixing device (11); The fixing device (11) comprises a flange upper cover (3), a metal window flange (1), and a base (2); the base (2) is provided with a groove (21); a boss (52) is provided in the middle of the electrode terminal (5); the boss (52) is correspondingly embedded in the groove (21).

2. A vacuum device according to claim 1, characterized in that: The upper and lower halves of the electrode terminal (5) are respectively provided with a horizontal through hole (51), and the top and tail ends are provided with vertical threaded inner holes (53), and the horizontal through hole (51) and the vertical threaded inner hole (53) are perpendicular to each other and interpenetrate each other.

3. A vacuum device according to claim 2, characterized in that: The base (2) and the flange upper cover (3) are pressed and fixed to the electrode terminal (5) by four studs. The metal window flange (1) is buckled onto the base (2).

4. A vacuum device according to claim 3, characterized in that: The bottom of the boss (52), the bottom of the flange upper cover (3), and the bottom of the metal window flange (1) are all provided with sealing rings; The sealing ring is any one of a rubber sealing ring, a polytetrafluoroethylene sealing ring, a polyurethane sealing ring, a composite sealing ring, a silicone sealing ring, and a fluororubber sealing ring.

5. A vacuum device according to claim 3, characterized in that: The base (2) and the flange upper cover (3) are both made of insulating materials.

6. A vacuum device according to claim 3, characterized in that: The electrode terminal (5) is made of a metal material that is a good conductor.

7. A detection device for monitoring the contact position between a seed crystal and a melt, characterized in that: The vacuum device comprises the vacuum device according to any one of claims 3 to 6, and further comprises a wire (4) and a multimeter (9).

8. A detection device for monitoring the contact position between a seed crystal and a melt according to claim 7, characterized in that: One end of the wire (4) passes through the horizontal through hole (51) respectively; the fixing screw (6) cooperates with the vertical threaded inner hole (53) to press the wire (4); The electrodes at the upper parts of the two electrode terminals (5) are respectively connected to the positive and negative electrodes of a multimeter (9) via wires (4); The electrodes at the lower parts of the two electrode terminals (5) are respectively connected to the devices to be detected via wires (4).

9. A detection device for monitoring the contact position between a seed crystal and a melt according to claim 8, characterized in that: The wire of the conductor (4) is any one of copper, aluminum, rhenium, tungsten, nickel or alloy metal materials thereof.

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