Growth device of N-type silicon carbide crystal

Abstract

The invention provides a growth device of N-type silicon carbide crystals, and relates to the technical field of semiconductors. The weight sensor and the connecting assembly are additionally arranged, so that the weight sensor is connected with the seed crystal support based on the connecting assembly; according to the method, a weight sensor is arranged, namely a seed crystal support provided with seed crystals is hung below the weight sensor, so that the weight parameters of the seed crystal support in the growth process are monitored in real time, the growth rate of the prepared N-type silicon carbide crystals is determined according to the change condition of the weight parameters in cooperation with an upper computer, and the growth parameters of the prepared N-type silicon carbide crystals are adjusted in real time according to the growth rate. The growth rate of the prepared N-type silicon carbide crystal is within the target growth rate range, the problem that the resistivity is uneven due to the fact that the growth rate changes due to temperature field fluctuation is solved, and the purpose of improving the resistivity uniformity of the N-type silicon carbide crystal is achieved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a growth device for N-type silicon carbide crystals. Background Art

[0002] Silicon carbide belongs to the third generation of semiconductor materials, and has the advantages of wide bandgap, high thermal conductivity, high critical breakdown field strength, high electron saturation drift rate, etc. Therefore, it has great application prospects in the field of semiconductor manufacturing. In the field, it is usually required that the silicon carbide crystal used to manufacture electronic devices is N-type silicon carbide crystal, and it must have uniform resistivity.

[0003] Silicon carbide crystal growth mainly uses the Physical Vapor Transportation (PVT) method, which has harsh growth conditions. The temperature field is easily corroded during the growth process, causing fluctuations, making it difficult to control the temperature field. Even a small fluctuation may have a significant impact on the growth of N-type silicon carbide crystals, causing a drastic change in the growth rate of N-type silicon carbide crystals and causing uneven resistivity.

[0004] Therefore, how to improve the uniformity of the resistivity of N-type silicon carbide crystals is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] In view of the above problems, the present application provides a growth device for N-type silicon carbide crystals to achieve the purpose of improving the uniformity of the resistivity of N-type silicon carbide crystals. The specific scheme is as follows:

[0006] In a first aspect, the present application provides a growth device for an N-type silicon carbide crystal, the growth device for an N-type silicon carbide crystal comprising: a seed crystal holder provided with a seed crystal, a crucible, a connection assembly, and a weight sensor;

[0007] The seed crystal holder is located at an opening side of the crucible, the weight sensor is located at a side of the seed crystal holder away from the crucible, and the connecting assembly is respectively connected to the seed crystal holder and the weight sensor;

[0008] The weight sensor is connected to a host computer, and is used to collect weight parameters of a target component, so that the host computer can determine the growth rate of the prepared N-type silicon carbide crystal according to changes in the weight parameters, and can also adjust the growth parameters of the prepared N-type silicon carbide crystal according to the growth rate, so that the growth rate of the prepared N-type silicon carbide crystal is within a target growth rate range; wherein the target component includes the seed crystal holder.

[0009] Preferably, in the above-mentioned N-type silicon carbide crystal growth device, the connecting assembly is connected to the seed crystal holder by means of a threaded connection or a hook connection.

[0010] Preferably, in the above-mentioned N-type silicon carbide crystal growth device, the N-type silicon carbide crystal growth device also includes: a sealing ring arranged around the crucible; the upper end of the sealing ring is connected to the outer side wall of the seed crystal holder, and the target component also includes the sealing ring.

[0011] Preferably, in the above-mentioned N-type silicon carbide crystal growth device, the outer side wall of the seed crystal holder is provided with a first thread;

[0012] The upper end of the inner side wall of the sealing ring is provided with a second thread that cooperates with the first thread.

[0013] Preferably, in the above-mentioned N-type silicon carbide crystal growth device, the height of the seed crystal holder is H1, and the height of the sealing ring is H2;

[0014] Among them, H2>H1.

[0015] Preferably, in the above-mentioned N-type silicon carbide crystal growth device, the crucible, the sealing ring and the seed crystal holder are placed concentrically.

[0016] Preferably, in the above-mentioned N-type silicon carbide crystal growth device, the diameter of the seed crystal holder and the inner diameter of the sealing ring are both Φ1, and the outer diameter of the crucible is Φ2;

[0017] Among them, 0<Φ1-Φ2≤0.5mm.

[0018] Preferably, in the above-mentioned N-type silicon carbide crystal growth device, the lower end of the inner side wall of the sealing ring is provided with K first protrusions, K ≥ 1, and K is a positive integer;

[0019] The inner diameter of the first protrusion is Φ3, and the outer diameter of the crucible is Φ2;

[0020] Among them, 0<Φ3-Φ2≤0.5mm.

[0021] Preferably, in the above-mentioned N-type silicon carbide crystal growth device, the inner side wall of the sealing ring is provided with a second protrusion;

[0022] The second protrusion contacts the lower surface of the seed crystal holder.

[0023] Preferably, in the above-mentioned N-type silicon carbide crystal growth device, a protective coating is provided on the inner side wall of the sealing ring and the outer side wall of the crucible opposite to the inner side wall of the sealing ring;

[0024] The protective coating is a hafnium boride coating, a tantalum carbide coating, a hafnium carbide coating, a niobium carbide coating, a tantalum hafnium carbide coating or a tantalum carbide coating.

[0025] By means of the above technical scheme, the present application provides a growth device for N-type silicon carbide crystals, by adding a weight sensor and a connecting component, the weight sensor is connected to the seed crystal holder based on the connecting component; that is, a seed crystal holder provided with a seed crystal is suspended under the weight sensor, so as to monitor the weight parameters of the seed crystal holder in real time during the growth process, cooperate with the upper computer to determine the growth rate of the prepared N-type silicon carbide crystal according to the change of the weight parameter, and adjust the growth parameters of the prepared N-type silicon carbide crystal in real time according to the growth rate, so that the growth rate of the prepared N-type silicon carbide crystal is within the target growth rate range, solves the problem of uneven resistivity caused by changes in growth rate due to temperature field fluctuations, and achieves the purpose of improving the resistivity uniformity of the N-type silicon carbide crystal. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.

[0027] Figure 1 A schematic structural diagram of an N-type silicon carbide crystal growth device provided in an embodiment of the present invention;

[0028] Figure 2 A partial structural schematic diagram of an N-type silicon carbide crystal growth device provided in an embodiment of the present invention;

[0029] Figure 3 A schematic structural diagram of another N-type silicon carbide crystal growth device provided in an embodiment of the present invention;

[0030] Figure 4 A partial structural schematic diagram of another N-type silicon carbide crystal growth device provided in an embodiment of the present invention;

[0031] Figure 5 A schematic structural diagram of another N-type silicon carbide crystal growth device provided in an embodiment of the present invention;

[0032] Figure 6 A partial structural schematic diagram of another N-type silicon carbide crystal growth device provided in an embodiment of the present invention;

[0033] Figure 7 A schematic diagram showing a comparison between the resistivity uniformity of each slice of the N-type silicon carbide crystal prepared by the technical solution of the present application and the resistivity uniformity of each slice of the N-type silicon carbide crystal prepared by the prior art solution;

[0034] Figure 8 Schematic diagram for comparing the average resistivity of each slice of the N-type silicon carbide crystal prepared by the technical solution of the present application with the average resistivity of each slice of the N-type silicon carbide crystal prepared by the prior art solution. DETAILED DESCRIPTION

[0035] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application. The terms used in the implementation mode of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application. It is known to those skilled in the art that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] It should be noted that the directional words appearing in the present invention are based on the relative position relationship shown in the drawings and cannot be used as an absolute limitation to the present application.

[0038] refer to Figure 1 , Figure 1 A schematic diagram of the structure of a growth device for N-type silicon carbide crystal provided in an embodiment of the present invention. The growth device for N-type silicon carbide crystal provided in an embodiment of the present invention comprises: a seed crystal holder 12 provided with a seed crystal 11, a crucible 13, a connecting assembly 14 and a weight sensor 15; wherein the crucible 13 contains a growth raw material for growing N-type silicon carbide crystal.

[0039] The seed crystal holder 12 is located at an opening side of the crucible 13 , the weight sensor 15 is located at a side of the seed crystal holder 12 away from the crucible 13 , and the connecting component 14 connects the seed crystal holder 12 and the weight sensor 15 , respectively.

[0040] The weight sensor 15 is connected to a host computer, and is used to collect weight parameters of a target component, so that the host computer can determine the growth rate of the prepared N-type silicon carbide crystal according to changes in the weight parameters, and can also adjust the growth parameters of the prepared N-type silicon carbide crystal according to the growth rate, so that the growth rate of the prepared N-type silicon carbide crystal is within a target growth rate range; wherein the target component includes the seed crystal holder 12.

[0041] Specifically, in the embodiment of the present invention, the seed crystal holder 12, the crucible 13, the connecting component 14 and the weight sensor 15 are all arranged in the furnace chamber 16, and the furnace chamber 16 is provided with an air inlet 17; the weight sensor 15 is arranged in the central area of ​​the top of the furnace chamber 16, and the connecting component 14 is arranged below the weight sensor 15, and the seed crystal holder 12 is connected below the connecting component 14, and the connecting component 14 is optionally connected to the seed crystal holder 12 by a threaded connection or a hook connection; the weight sensor 15 includes but is not limited to being connected to the host computer via a cable 18. It should be noted that Figure 1 The upper computer is not shown in the figure.

[0042] In other words, in the embodiment of the present application, a weight sensor 15 and a connecting component 14 are added, so that the weight sensor 15 is connected to the seed crystal holder 12 based on the connecting component 14; that is, a seed crystal holder 12 provided with a seed crystal 11 is suspended below the weight sensor 15, so as to monitor the weight parameters of the seed crystal holder 12 in real time during the growth process, cooperate with the upper computer to determine the mass change of the prepared N-type silicon carbide crystal according to the change of the weight parameter, further determine the growth rate of the prepared N-type silicon carbide crystal, and adjust the growth parameters of the prepared N-type silicon carbide crystal in real time according to the growth rate, so that the growth rate of the prepared N-type silicon carbide crystal is within the target growth rate range, solve the problem of uneven resistivity caused by changes in growth rate due to temperature field fluctuations, and achieve the purpose of improving the resistivity uniformity of the N-type silicon carbide crystal.

[0043] Specifically, N-type silicon carbide crystals are generally achieved by nitrogen doping. The nitrogen concentration determines the resistivity of the N-type silicon carbide crystals. Temperature field fluctuations will cause changes in the growth rate of the N-type silicon carbide crystals, causing changes in the nitrogen doping amount. The uniformity of nitrogen doping will affect the resistivity of the N-type silicon carbide crystals and have a great impact on the consistency of the device technical parameters. It can be concluded that the resistivity of the N-type silicon carbide crystal will be directly affected by the nitrogen doping amount, while the growth rate and the gas filling ratio will directly affect the nitrogen doping amount; therefore, according to the growth rate, the appropriate gas filling ratio, total gas filling amount, and pulling rate and other parameters can be statistically analyzed and summarized, and the growth parameters of the prepared N-type silicon carbide crystals can be adjusted in real time accordingly, such as the power, gas filling ratio, total gas filling amount, and pulling rate and other growth parameters during the growth of the N-type silicon carbide crystals. The specific logic is as follows:

[0044] Based on the positive correlation between the growth rate v, power P and pulling rate γ, we can get:

[0045]

[0046] Among them, k>0, which is the first coefficient obtained based on historical data analysis; t represents time, and P(t) represents the power changing with time by way of example; if the actual v(t) value deviates from the target value, the power P or the pulling rate γ is adjusted proportionally.

[0047] If the total gas filling volume Q is constant, the larger the filling ratio α of nitrogen and argon, the more nitrogen doping; if the filling ratio α is constant, the larger the total gas filling volume Q, the more nitrogen doping will be. Therefore, it can be obtained that:

[0048]

[0049] Among them, ρ 0 is the target resistivity; c is the second coefficient obtained based on the historical data analysis; t represents time, and exemplary v(t) represents the growth rate that changes with time.

[0050] It can be seen from the above description that the N-type silicon carbide crystal growth device provided in the embodiment of the present invention can realize the control of the crystal growth process, optimize the uniformity of doping, and effectively improve the consistency of the resistivity within the N-type silicon carbide crystal. In other words, by real-time monitoring of the growth rate of the N-type silicon carbide crystal, the parameters such as pulling and doping can be adjusted in real time to achieve the purpose of optimizing the resistivity of the N-type silicon carbide crystal.

[0051] In an optional embodiment of the present invention, Figure 1 As shown, the N-type silicon carbide crystal growth device provided by the embodiment of the present invention further includes: a sealing ring 19 arranged around the crucible 13 .

[0052] The upper end of the sealing ring 19 is connected to the outer side wall of the seed crystal holder 12 , and the target component also includes the sealing ring 19 .

[0053] Specifically, in the embodiment of the present invention, a sealing ring 19 is provided to further seal the crucible 13 to prevent the gas in the crucible 13 from overflowing into the furnace chamber 16. Figure 2 , Figure 2 A partial structural schematic diagram of an N-type silicon carbide crystal growth device provided in an embodiment of the present invention; Figure 2 As shown, the outer wall of the seed crystal holder 12 is provided with a first thread 20; the upper end of the inner wall of the sealing ring 19 is provided with a second thread 21 that cooperates with the first thread 20. That is to say, one possible implementation of the embodiment of the present invention is to assemble the sealing ring 19 and the seed crystal holder 12 by threaded connection, so as to achieve the purpose of convenient disassembly and assembly, convenient maintenance and convenient replacement of components.

[0054] like Figure 1 and Figure 2As shown, the height of the seed crystal holder 12 is H1, and the height of the sealing ring 19 is H2; wherein H2>H1. The height of the area where the second thread 21 is located is H1, so as to achieve the purpose of perfect fit between the first thread 20 and the second thread 21 after assembly; further, in the case of H2>H1, the sealing ring 19 and the seed crystal holder 12 are arranged on the opening side of the crucible 13 in a manner equivalent to a cap buckle, so as to achieve sealing of the crucible 13.

[0055] In an optional embodiment of the present invention, Figure 1 As shown, the diameter of the seed crystal holder 12 and the inner diameter of the sealing ring 19 are both Φ1, and the outer diameter of the crucible 13 is Φ2.

[0056] Among them, 0<Φ1-Φ2≤0.5mm.

[0057] Specifically, in the embodiment of the present invention, the crucible 13, the sealing ring 19 and the seed crystal holder 12 are placed concentrically, and a certain gap is ensured between the outer wall of the crucible 13 and the sealing ring 19 under the setting of 0<Φ1-Φ2≤0.5mm. The upper edge of the opening of the crucible 13 is in contact with the seed crystal holder 12, ensuring that the sealing ring 19 can seal the gas while ensuring that the crucible 13 and the sealing ring 19 can move freely in the vertical direction without friction.

[0058] In an optional embodiment of the present invention, reference Figure 3 , Figure 3 A schematic diagram of the structure of another N-type silicon carbide crystal growth device provided in an embodiment of the present invention, referring to Figure 4 , Figure 4 A partial structural diagram of another N-type silicon carbide crystal growth device provided in an embodiment of the present invention. In the embodiment of the present invention, K first protrusions 22 are arranged at the lower end of the inner side wall of the sealing ring 19, where K≥1 and K is a positive integer.

[0059] The inner diameter of the first protrusion 22 is Φ3, and the outer diameter of the crucible 13 is Φ2.

[0060] Among them, 0<Φ3-Φ2≤0.5mm.

[0061] Specifically, in the embodiment of the present invention, K=2 is used as an example for explanation. There is a gap between two adjacent first protrusions 22. K first protrusions 22 are provided to further improve the sealing performance of the sealing ring 19 on the crucible 13. The distance between the first protrusion 22 closest to the second thread 21 and the lower edge of the second thread 21 is greater than or equal to 30 mm, that is, there is a relationship of H3≥30 mm. The crucible 13, the sealing ring 19 and the seed crystal holder 12 are placed concentrically. Under the setting of 0<Φ3-Φ2≤0.5 mm, a certain gap is ensured between the outer wall of the crucible 13 and the first protrusion 22. The upper edge of the opening of the crucible 13 contacts the seed crystal holder 12, ensuring that the sealing ring 19 can seal the gas while ensuring that the crucible 13 and the first protrusion 22 can move freely in the vertical direction without friction.

[0062] In an optional embodiment of the present invention, reference Figure 5 , Figure 5 A schematic diagram of a structure of another N-type silicon carbide crystal growth device provided in an embodiment of the present invention, referring to Figure 6 , Figure 6 A partial structural diagram of another N-type silicon carbide crystal growth device provided in an embodiment of the present invention. In the embodiment of the present invention, a second protrusion 23 is provided on the inner side wall of the sealing ring 19 .

[0063] The second protrusion 23 contacts the lower surface of the seed crystal holder 12 .

[0064] Specifically, in the embodiment of the present invention, a second protrusion 23 is further provided at the lower edge of the second thread 21, so that after the seed crystal holder 12 and the sealing ring 19 are tightened, the second protrusion 23 and the lower surface of the seed crystal holder 12 are completely closed, so as to further improve the sealing performance of the sealing ring 19 to the crucible 13. Optionally, the inner diameter of the second protrusion 23 is also Φ4, wherein 0<Φ4-Φ2≤0.5mm. It should be noted that Φ3 and Φ4 may be equal or unequal, which is not limited in the embodiment of the present invention and can be determined according to actual conditions.

[0065] In an optional embodiment of the present invention, a protective coating is disposed on the inner side wall of the sealing ring 19 and the outer side wall of the crucible 13 opposite to the inner side wall of the sealing ring 19 .

[0066] The protective coating is a hafnium boride coating, a tantalum carbide coating, a hafnium carbide coating, a niobium carbide coating, a tantalum hafnium carbide coating or a tantalum carbide coating.

[0067] Specifically, in the embodiment of the present invention, a protective coating is used to protect the area at the height H2-H1 on the upper edge of the outer wall of the crucible 13 and the inner wall of the sealing ring 19 to prevent corrosion due to gas overflow from the crucible 13, which would affect the sealing performance and the free movement between the crucible 13 and the sealing ring 19. The sealing ring 19 can also be reused, thereby increasing the service life of the sealing ring 19 and reducing the cost of using the growth device.

[0068] Based on the above embodiments of the present invention, the technical solution of the present application and the technical effects that can be brought about are further explained in the form of specific embodiments below.

[0069] Since the growth temperature of N-type silicon carbide crystals is usually over 2000°C, the heating body and the heat preservation body are very easy to change in such a high temperature environment. Even a small fluctuation may have a significant impact on the growth of N-type silicon carbide crystals, resulting in a drastic change in the growth rate of the prepared N-type silicon carbide crystals, causing non-uniform resistivity. The technical solution of the present invention monitors the growth rate of N-type silicon carbide crystals in real time, and adjusts the growth parameters such as the doping amount in real time based on this, thereby avoiding the problem of non-uniform resistivity caused by temperature field fluctuations during the growth of N-type silicon carbide crystals.

[0070] In the N-type silicon carbide crystal growth device provided by the embodiment of the present invention, the outer diameter of the crucible 13 is 200mm, that is, Φ2=200mm, and a tantalum carbide coating is provided in the upper edge of the outer wall of the crucible 13 at a height of 30mm; a growth raw material for growing N-type silicon carbide crystals is placed in the crucible 13; a cylindrical graphite heating material is provided on the outer wall of the crucible 13 to provide a heat source for the growing raw material; a graphite felt insulation material is provided on the outer wall of the heating material to isolate the high temperature of the heating material, prevent the induction coil from being damaged by high temperature, and maintain the temperature field structure; an induction coil is provided on the outer wall of the insulation material to generate induction heating of the heating material; a seed-bearing device is provided on the outer wall of the insulation material to generate induction heating of the heating material; a seed-bearing device is provided on the opening side of the crucible 13 to generate induction heating of the heating material; a seed-bearing device is provided on the outer wall of the insulation material to generate induction heating of the heating material; a seed-bearing device is provided on the opening side of the crucible 13 to generate induction heating of the heating material; a seed-bearing device is provided on the outer wall of the insulation material to generate induction heating of the heating material; a seed-bearing device is provided on the outer wall of the crucible 13 ... opening side of the crucible 13 to generate induction heating of the heating material The seed crystal holder 12 of the crystal 11 has a height of 25 mm, i.e. H1=25 mm, and a diameter of 210.1 mm, i.e. Φ1=210.1 mm, and a first thread 20 is arranged on the outer wall of the seed crystal holder 12; the height of the sealing ring 19 is 60 mm, i.e. H2=60 mm, and an inner diameter is 210.1 mm, i.e. Φ1=210.1 mm, and an outer diameter is 230 mm, and three first protrusions 22 are arranged on the lower end, and the height of the first protrusions 22 are all 5 mm, and the inner diameter is 200.10 mm, i.e. Φ3=200.10 mm, and a tantalum carbide coating is arranged on the inner wall of the sealing ring 19, and a second thread 21 cooperating with the first thread 20 is arranged on the upper end of the inner wall of the sealing ring 19.

[0071] Use the seed crystal holder 12 to which the seed crystal 11 has been bonded to thread and tighten it with the sealing ring 19; combine the connecting piece on the seed crystal holder 12 with the connecting component 14 below the weight sensor 15, so that the seed crystal holder 12 with the sealing ring 19 is suspended below the weight sensor 15. After the connection is completed and it is freely suspended, record the value on the weight sensor 15, which represents the initial weight W0 of the seed crystal holder 12 and the sealing ring 19; center the crucible 13 in the cylindrical heating material, and then concentrically place the seed crystal holder 12 and the sealing ring 19 on top of the crucible 13, gently lower the seed crystal holder 12 and the sealing ring 19 so that the upper edge of the crucible 13 is in light contact with the seed crystal holder 12, and make the gap between the crucible 13 and the sealing ring 19 uniform; then place other insulation structures; slowly lift the crucible 13, check the current value of the weight sensor 15, and compare it with the initial weight W0 recorded previously; if it is inconsistent, gently move the crucible 13, and The crucible 13 is slowly pulled up again, and the values ​​are checked again to see if they are consistent. If not, the above operation is repeated. If they are consistent, it can be considered that the crucible 13 is just in contact with the seed crystal holder 12 and the sealing ring 19, or the contact has little effect on the weight sensor 15 and can be ignored. During the growth process, the upper computer is used to determine the mass change of the prepared N-type silicon carbide crystal according to the changes in the mass of the sealing ring 19, the seed crystal holder 12 and the crystal collected by the weight sensor 15, and further determine the growth rate of the prepared N-type silicon carbide crystal, and adjust the growth parameters of the prepared N-type silicon carbide crystal in real time according to the growth rate, such as adjusting the inflation volume Q, the inflation ratio α and the pulling rate γ in real time, so that the growth rate of the prepared N-type silicon carbide crystal is within the target growth rate range, so as to solve the problem of uneven resistivity caused by changes in the growth rate due to temperature field fluctuations, and achieve the purpose of improving the resistivity uniformity of the N-type silicon carbide crystal.

[0072] After being taken out of the furnace, the N-type silicon carbide crystal is cut, polished, and the resistivity of each piece of N-type silicon carbide crystal is tested.

[0073] Specifically, the resistivity uniformity in the resistivity test results of all slices (it should be noted that since the growth interface of the N-type silicon carbide crystal is a curved surface, the parts corresponding to different doping amounts at different growth stages may be in the same slice after being sliced, which leads to uneven resistivity within the slice) is plotted as a box plot in units of slices, and compared with the resistivity uniformity of the N-type silicon carbide crystal prepared by the prior art solution after slicing, such as Figure 7 As shown, Figure 7This is a schematic diagram comparing the resistivity uniformity of each slice of the N-type silicon carbide crystal prepared by the technical solution of this application with the resistivity uniformity of each slice of the N-type silicon carbide crystal prepared by the prior art solution; it can be seen that the mean and median of the resistivity uniformity in the box plot have significantly decreased, and the box distribution has obviously narrowed. The average resistivity of each slice is then plotted into a box plot and compared with the average resistivity of the wafer after cutting, grinding and polishing with the same processing technology of the N-type silicon carbide crystal prepared by the prior art solution, as shown in Figure 2. Figure 8 As shown, Figure 8 A schematic diagram showing a comparison between the average resistivity of each slice of the N-type silicon carbide crystal prepared by the technical solution of the present application and the average resistivity of each slice of the N-type silicon carbide crystal prepared by the prior art solution; it can be seen from the box plot that the median and average resistivity of each slice of the N-type silicon carbide crystal prepared by the technical solution of the present application after slicing are closer to the target resistivity ρ 0 , and the box range is obviously narrower, indicating that the resistivity of the N-type silicon carbide crystal prepared by the technical solution of the present application is well controlled, the resistivity qualification rate can reach 99.8%, and the resistivity uniformity can reach 95%.

[0074] It can be seen from the above description that the N-type silicon carbide crystal growth device provided in the embodiment of the present invention can realize the control of the crystal growth process, optimize the uniformity of doping, and effectively improve the consistency of the resistivity within the N-type silicon carbide crystal. In other words, by real-time monitoring of the growth rate of the N-type silicon carbide crystal, the parameters such as pulling and doping can be adjusted in real time to achieve the purpose of optimizing the resistivity of the N-type silicon carbide crystal.

[0075] The above is a detailed introduction to an N-type silicon carbide crystal growth device provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technicians in this field, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0076] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment that includes a series of elements is inherent to the elements, or also includes elements inherent to these processes, methods, articles or equipment. In the absence of further restrictions, the elements defined by the sentence "including a..." do not exclude the existence of other identical elements in the process, method, article or equipment that includes the elements.

[0077] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for growing N-type silicon carbide crystals, characterized in that: The N-type silicon carbide crystal growth device comprises: a seed crystal holder provided with a seed crystal, a crucible, a connecting component and a weight sensor; The seed crystal holder is located at an opening side of the crucible, the weight sensor is located at a side of the seed crystal holder away from the crucible, and the connecting assembly is respectively connected to the seed crystal holder and the weight sensor; The weight sensor is connected to a host computer, and is used to collect weight parameters of a target component, so that the host computer can determine the growth rate of the prepared N-type silicon carbide crystal according to changes in the weight parameters, and can also adjust the growth parameters of the prepared N-type silicon carbide crystal according to the growth rate, so that the growth rate of the prepared N-type silicon carbide crystal is within a target growth rate range; wherein the target component includes the seed crystal holder.

2. The N-type silicon carbide crystal growth device according to claim 1, characterized in that: The connection assembly is connected to the seed crystal holder by a threaded connection or a hook connection.

3. The N-type silicon carbide crystal growth device according to claim 1, characterized in that: The N-type silicon carbide crystal growth device further includes: a sealing ring arranged around the crucible; the upper end of the sealing ring is connected to the outer side wall of the seed crystal holder, and the target component also includes the sealing ring.

4. The N-type silicon carbide crystal growth device according to claim 3, characterized in that: The outer side wall of the seed crystal holder is provided with a first thread; The upper end of the inner side wall of the sealing ring is provided with a second thread that cooperates with the first thread.

5. The N-type silicon carbide crystal growth device according to claim 3, characterized in that: The height of the seed crystal holder is H1, and the height of the sealing ring is H2; Among them, H2>H1.

6. The N-type silicon carbide crystal growth device according to claim 3, characterized in that: The crucible, the sealing ring and the seed crystal holder are placed concentrically.

7. The N-type silicon carbide crystal growth device according to any one of claims 3 to 6, characterized in that: The diameter of the seed crystal holder and the inner diameter of the sealing ring are both Φ1, and the outer diameter of the crucible is Φ2; Among them, 0<Φ1-Φ2≤0.5mm.

8. The N-type silicon carbide crystal growth device according to any one of claims 3 to 6, characterized in that: The lower end of the inner side wall of the sealing ring is provided with K first protrusions, K ≥ 1, and K is a positive integer; The inner diameter of the first protrusion is Φ3, and the outer diameter of the crucible is Φ2; Among them, 0<Φ3-Φ2≤0.5mm.

9. The N-type silicon carbide crystal growth device according to claim 8, characterized in that: The inner side wall of the sealing ring is provided with a second protrusion; The second protrusion contacts the lower surface of the seed crystal holder.

10. The N-type silicon carbide crystal growth device according to any one of claims 3 to 6, characterized in that: The inner side wall of the sealing ring and the outer side wall of the crucible opposite to the inner side wall of the sealing ring are both provided with a protective coating; The protective coating is a hafnium boride coating, a tantalum carbide coating, a hafnium carbide coating, a niobium carbide coating, a tantalum hafnium carbide coating or a tantalum carbide coating.

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