Composite heating type silicon carbide crystal growing furnace

Abstract

The utility model relates to a composite heating type silicon carbide crystal growing furnace which comprises a furnace body, a heater assembly and a crucible, the heater assembly and the crucible are arranged in an inner cavity of the furnace body, the crucible is located in the heater assembly, a heat preservation layer is arranged between the furnace body and the heater assembly, and the heater assembly is fixed to the furnace body through an electrode. A crucible is arranged in the furnace body, a seed crystal disc is fixedly mounted on the crucible, seed crystals are adhered to the inner side of the seed crystal disc, raw materials are stored in the crucible, the heater assembly comprises an upper resistance heater and a lower resistance heater, and the upper resistance heater is located on the side, close to a top plate of the furnace body, of the lower resistance heater. The upper resistance heater and the lower resistance heater are used as heat sources, the heating area is increased, the melting speed of silicon materials in the crucible is increased, the axial temperature gradient is more easily formed in the furnace body, and large-size crystals are formed.

Description

Technical Field

[0001] The present application relates to semiconductor technology, and in particular to a composite heating type silicon carbide crystal growth furnace. Background Art

[0002] Silicon carbide (SiC) single crystal material has the characteristics of wide band gap, high critical electric field, high thermal conductivity, high carrier saturation drift velocity, etc. It is an important third-generation semiconductor material and is suitable for use as a substrate for power / RF devices. At present, the industrial growth of silicon carbide crystals mainly uses the physical vapor transport (PVT) method, which involves complex multi-physical field coupling problems of multi-phase, multi-component, multiple heat and mass transfer and magneto-electric heat flow interactions. Therefore, the design of the PVT growth system is difficult, and the process parameters during the crystal growth process are difficult to measure and control, resulting in the quality defects of the grown silicon carbide crystals being difficult to control and the crystal size being small, resulting in the high cost of devices with SiC as the substrate. Utility Model Content

[0003] In order to overcome the above-mentioned defects, the present application provides a composite heating silicon carbide crystal growth furnace, which uses an upper resistance heater and a lower resistance heater as heat sources, increases the heating area, accelerates the melting rate of the silicon material in the crucible, makes it easier to form an axial temperature gradient in the furnace body, and utilizes the molding of large-size crystals.

[0004] The technical solution adopted by this application to solve its technical problems is:

[0005] A composite heating type silicon carbide crystal growth furnace comprises a furnace body and a heater assembly and a crucible placed in the inner cavity of the furnace body, the crucible is located in the heater assembly, an insulation layer is provided between the furnace body and the heater assembly, the heater assembly is fixed to the furnace body through electrodes, a seed crystal disk is fixedly installed on the crucible, seed crystals are adhered to the inner side of the seed crystal disk, raw materials are stored in the crucible, the heater assembly comprises an upper resistance heater and a lower resistance heater, the upper resistance heater is located on the top plate side of the lower resistance heater close to the furnace body.

[0006] Optionally, the upper resistance heater is fixed to the top plate of the furnace body through the electrodes, the lower resistance heater is fixed to the bottom plate of the furnace body through the electrodes, and heat dissipation holes are provided on the top plate.

[0007] Optionally, the seed crystal plate is mounted on the top of the crucible, a base is fixedly mounted on the bottom of the crucible, the base is fixedly mounted on the bottom plate, and a temperature measuring hole is provided in the base.

[0008] Optionally, the height of the upper resistance heater is smaller than the height of the lower resistance heater, and a gap is provided between the upper resistance heater and the lower resistance heater.

[0009] Optionally, the upper resistance heater is a hollow cylindrical structure, comprising a side wall and a top wall fixedly connected, a square groove is axially opened on the side wall, a tortuous channel is opened on the top wall, and a first mounting hole is opened on the top wall.

[0010] Optionally, the upper resistance heater has an axisymmetric structure, and the square groove includes a first square groove and a second square groove, the first square groove is connected to the outside of the upper resistance heater from the upper end of the side wall, and the second square groove is connected to the outside of the upper resistance heater from the lower end of the side wall, and the first square groove and the second square groove are arranged at intervals from each other.

[0011] Optionally, the lower resistance heater is in a hollow cylindrical structure, a narrow slot is provided in the axial direction of the lower resistance heater, the lower end of the lower resistance heater extends radially inward to form a lug, and a second mounting hole is provided on the lug.

[0012] Optionally, the lower resistance heater has an axisymmetric structure, and the narrow groove includes a first narrow groove and a second narrow groove, the first narrow groove is connected from the upper end of the lower resistance heater to the outer side of the lower resistance heater, and the second narrow groove is connected from the lower end of the lower resistance heater to the outer side of the lower resistance heater, and the first narrow groove and the second narrow groove are arranged at intervals from each other.

[0013] The beneficial effects of this application are:

[0014] (1) In the present application, the resistance heater uses a resistor as a heat source and uses thermal radiation as the main heat transfer method to heat the outer wall of the crucible, and then heats the raw material through heat conduction of the crucible. The heater components are arranged around the crucible, on the top and on the bottom to achieve temperature control in the local area. After the raw material is heated, it decomposes, and the SiC gas phase component of the product is transported to the low-temperature seed crystal surface on the top of the crucible under the drive of the temperature gradient to recrystallize and form large-sized crystals.

[0015] (2) The upper resistance heater and the lower resistance heater are used in the present application, which can heat the furnace bottom, furnace top and sides at the same time, increase the heating area, speed up the melting speed of the silicon material in the crucible, and at the same time, by adjusting the power of the upper resistance heater and the lower resistance heater, it is easier to form an axial temperature gradient in the furnace body, and utilize the molding of large-sized crystals. The crystal growth furnace of the present application has a simple structure, effectively avoids the phenomenon of uneven heating, reduces the consumption of electricity, and saves the production cost of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1It is a schematic diagram of the structure of the growth furnace in this application;

[0017] Figure 2 This is one of the structural schematic diagrams of the upper resistance heater in this application;

[0018] Figure 3 This is the second structural schematic diagram of the upper resistance heater in this application;

[0019] Figure 4 This is the third structural schematic diagram of the upper resistance heater in this application;

[0020] Figure 5 This is the fourth structural diagram of the upper resistance heater in this application;

[0021] Figure 6 One of the structural schematic diagrams of the lower resistance heater in this application;

[0022] Figure 7 This is the second structural schematic diagram of the lower resistance heater in this application;

[0023] Figure 8 for Figure 7 Sectional view along AA;

[0024] Fig. 9 for Figure 8 Sectional view along the middle line BB;

[0025] In the figure: 10-furnace body, 11-top plate, 12-bottom plate, 13-insulation layer, 14-electrode, 15-heat radiation zone, 16-heat dissipation hole, 20-upper resistance heater, 21-side wall, 22-top wall, 23-first square groove, 24-second square groove, 25-channel, 26-first mounting hole, 30-lower resistance heater, 31-first narrow slot, 32-second narrow slot, 33-lug, 34-second mounting hole, 40-crucible, 41-top, 42-bottom, 43-seed crystal plate, 44-seed crystal, 45-base, 46-temperature measuring hole, 47-raw material. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the embodiments described in the present application are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the following drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the objects used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0028] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0029] Example: Figure 1-9 As shown, a composite heating type silicon carbide crystal growth furnace comprises a furnace body 10 and a heater assembly and a crucible 40 placed in the inner cavity of the furnace body 10, wherein the crucible 40 is located in the heater assembly, and a heat preservation layer 13 is provided between the furnace body 10 and the heater assembly, wherein the heater assembly is fixed to the furnace body 10 through an electrode 14, a seed crystal plate 43 is fixedly installed on the crucible 40, and a seed crystal 44 is adhered to the inner side of the seed crystal plate 43, and a raw material 47 is stored in the crucible 40, wherein the heater assembly comprises an upper resistance heater 20 and a lower resistance heater 30, wherein the upper resistance heater 20 is located on the side of the lower resistance heater 30 close to the top plate 11 of the furnace body 10. The raw material 47 can be SiC raw material powder. The direction of the top plate 11 of the furnace body 10 is defined as the upper side of the furnace body, and the direction of the bottom plate 12 of the furnace body 10 is defined as the lower side of the furnace body, and then the upper resistance heater 20 is located above the lower resistance heater 30. The cavity of the furnace body 10 inside the heat preservation layer 13 is a heat radiation zone 15.

[0030] In the present application, a heat preservation layer 13 is provided in the furnace body 10, a heater assembly is provided inside the heat preservation layer 13, and a crucible is provided inside the heater assembly. Different from the induction heating method, the resistance heater in the present application uses a resistor as a heat source, and uses thermal radiation as the main heat transfer method to heat the outer wall of the crucible, and then heats the raw material 47 through heat conduction of the crucible. The heater assembly is arranged around, on the top and on the bottom of the crucible to achieve temperature control in a local area. The raw material is decomposed after being heated, and the SiC gas phase component of the product is transported to the low-temperature seed crystal surface at the top of the crucible under the drive of the temperature gradient to recrystallize to form large-sized crystals. The temperature gradient in the raw material area is closely related to the limiting growth rate of the crystal. Increasing the temperature gradient in the raw material area can increase the crystal growth rate.

[0031] The upper resistance heater and the lower resistance heater are used in the present application, and the furnace bottom, the furnace top and the side can be heated at the same time, thereby increasing the heating area and accelerating the melting speed of the silicon material in the crucible. At the same time, by adjusting the power of the upper resistance heater and the lower resistance heater, it is easier to form an axial temperature gradient in the furnace body, which is conducive to the formation of large-sized crystals. The crystal growth furnace of the present application has a simple structure, effectively avoids the phenomenon of uneven heating, reduces the consumption of electric energy, and saves the production cost of the product.

[0032] like Figure 1 As shown, the upper resistance heater 20 is fixed on the top plate 11 of the furnace body 10 through the electrode 14, and the electrode 14 extends to the outside of the top plate 11; the lower resistance heater 30 is fixed on the bottom plate 12 of the furnace body 10 through the electrode 14, and the electrode 14 extends to the outside of the bottom plate 12; the top plate 11 is provided with a heat dissipation hole 16. The heat dissipation hole 16 is mainly used to control the temperature gradient of the thermal field and guide the airflow.

[0033] like Figure 1 As shown, the seed crystal plate 43 is mounted on the top 41 of the crucible 40, the bottom 42 of the crucible 40 is fixedly mounted with a base 45, the base 45 is fixedly mounted on the bottom plate 12, and a temperature measuring hole 46 is provided in the base 45. The temperature measuring hole 46 can be used to grasp the temperature in the furnace body 10 in real time.

[0034] The height of the upper resistance heater 20 is smaller than the height of the lower resistance heater 30, and a gap is provided between the upper resistance heater 20 and the lower resistance heater 30. The upper resistance heater 20 is located in the upper space of the furnace body, and the lower resistance heater 30 is located in the lower space of the furnace body, with a gap between the two, so that the furnace bottom, furnace top and side can be heated at the same time, the heating area is increased, and the melting speed of the silicon material in the crucible is accelerated. At the same time, by adjusting the power of the upper resistance heater and the lower resistance heater, it is easier to form an axial temperature gradient in the furnace body, which is conducive to the formation of large-sized crystals.

[0035] like Figure 2-5 As shown, the upper resistance heater 20 is a hollow cylindrical structure, and the upper resistance heater 20 includes a side wall 21 and a top wall 22 that are fixedly connected, a square groove is provided in the axial direction on the side wall 21, a tortuous channel 25 is provided on the top wall 22, and a first mounting hole 26 is provided on the top wall 22. A fixing screw is inserted through the first mounting hole 26 to fix the electrode 14 on the upper resistance heater 20, and then the upper resistance heater 20 is fixedly installed on the top plate 11 of the furnace body 10 through the electrode 14.

[0036] like Figure 2 As shown, the upper resistance heater 20 is an axisymmetric structure, and the square grooves include a first square groove 23 and a second square groove 24. The first square groove 23 is connected to the outer side of the upper resistance heater 20 from the upper end of the side wall 21, and the second square groove 24 is connected to the outer side of the upper resistance heater 20 from the lower end of the side wall 21. The first square groove 23 and the second square groove 24 are arranged at intervals. Figure 1 and Figure 2 As shown, the top wall 22 of the upper resistance heater 20 is located above the crucible 40, and the side wall 21 of the upper resistance heater 20 is located outside the upper part of the crucible 40. The upper resistance heater 20 is used to heat the upper section of the furnace body 10. The first square groove 23 and the second square groove 24 are both closed at one end and open at the other end. The upper end of the first square groove 23 is an open end and the lower end is a closed end, and the upper end of the second square groove 24 is a closed end and the lower end is an open end.

[0037] like Figure 6-9 As shown, the lower resistance heater 30 is a hollow cylindrical structure, the lower resistance heater 30 is provided with a narrow slot along the axial direction, the lower end of the lower resistance heater 30 extends radially inward to form a lug 33, and the lug 33 is provided with a second mounting hole 34. A fixing screw is passed through the second mounting hole 34 to fix the electrode 14 on the lower resistance heater 30, and then the lower resistance heater 30 is fixedly mounted on the bottom plate 12 of the furnace body 10 through the electrode 14.

[0038] like Figure 6 As shown, the lower resistance heater 30 is an axisymmetric structure, and the slots include a first slot 31 and a second slot 32. The first slot 31 is connected to the outer side of the lower resistance heater 30 from the upper end of the lower resistance heater 30, and the second slot 32 is connected to the outer side of the lower resistance heater 30 from the lower end of the lower resistance heater 30. The first slot 31 and the second slot 32 are arranged at intervals from each other. Figure 1 and Figure 6The lower resistance heater 30 is shown to be located outside the lower portion of the crucible 40. The lower resistance heater 30 is used to heat the lower section of the furnace body 10. The first slot 31 and the second slot 32 are both closed at one end and open at the other end. The upper end of the first slot 31 is an open end and the lower end is a closed end, and the upper end of the second slot 32 is a closed end and the lower end is an open end.

[0039] It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, and these modifications and improvements are all within the scope of protection of the present application. Therefore, the scope of protection of the patent of the present application shall be subject to the attached claims.

Claims

1. A composite heating type silicon carbide crystal growth furnace, characterized in that: The invention comprises a furnace body (10), a heater assembly and a crucible (40) disposed in an inner cavity of the furnace body (10), wherein the crucible (40) is disposed in the heater assembly, a heat-insulating layer (13) is disposed between the furnace body (10) and the heater assembly, the heater assembly is fixed to the furnace body (10) via an electrode (14), a seed crystal plate (43) is fixedly mounted on the crucible (40), a seed crystal (44) is adhered to the inner side of the seed crystal plate (43), a raw material (47) is stored in the crucible (40), and the heater assembly comprises an upper resistance heater (20) and a lower resistance heater (30), wherein the upper resistance heater (20) is disposed on the side of the lower resistance heater (30) close to a top plate (11) of the furnace body (10).

2. The composite heating type silicon carbide crystal growth furnace according to claim 1, characterized in that: The upper resistance heater (20) is fixed to the top plate (11) of the furnace body (10) via the electrode (14), the lower resistance heater (30) is fixed to the bottom plate (12) of the furnace body (10) via the electrode (14), and a heat dissipation hole (16) is provided on the top plate (11).

3. The composite heating type silicon carbide crystal growth furnace according to claim 2, characterized in that: The seed crystal plate (43) is mounted on the top (41) of the crucible (40), the bottom (42) of the crucible (40) is fixedly mounted with a base (45), the base (45) is fixedly mounted on the bottom plate (12), and a temperature measuring hole (46) is provided in the base (45).

4. The composite heating type silicon carbide crystal growth furnace according to claim 1, characterized in that: The height of the upper resistance heater (20) is smaller than the height of the lower resistance heater (30), and a gap is provided between the upper resistance heater (20) and the lower resistance heater (30).

5. The composite heating type silicon carbide crystal growth furnace according to claim 1, characterized in that: The upper resistance heater (20) is in the form of a hollow cylindrical structure, comprising a side wall (21) and a top wall (22) that are fixedly connected, a square groove being provided in the axial direction on the side wall (21), a tortuous channel (25) being provided in the top wall (22), and a first mounting hole (26) being provided in the top wall (22).

6. The composite heating type silicon carbide crystal growth furnace according to claim 5, characterized in that: The upper resistance heater (20) has an axisymmetric structure, and the square groove comprises a first square groove (23) and a second square groove (24), wherein the first square groove (23) is connected to the outer side of the upper resistance heater (20) from the upper end of the side wall (21), and the second square groove (24) is connected to the outer side of the upper resistance heater (20) from the lower end of the side wall (21), and the first square groove (23) and the second square groove (24) are arranged at an interval from each other.

7. The composite heating type silicon carbide crystal growth furnace according to claim 1, characterized in that: The lower resistance heater (30) is in the form of a hollow cylindrical structure. A narrow slot is provided in the axial direction of the lower resistance heater (30). The lower end of the lower resistance heater (30) extends radially inward to form a lug (33). A second mounting hole (34) is provided on the lug (33).

8. The composite heating type silicon carbide crystal growth furnace according to claim 7, characterized in that: The lower resistance heater (30) has an axisymmetric structure, and the narrow groove includes a first narrow groove (31) and a second narrow groove (32), wherein the first narrow groove (31) is connected to the outer side of the lower resistance heater (30) from the upper end of the lower resistance heater (30), and the second narrow groove (32) is connected to the outer side of the lower resistance heater (30) from the lower end of the lower resistance heater (30), and the first narrow groove (31) and the second narrow groove (32) are arranged to be spaced apart from each other.

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