Method for high-efficiency purification of SiC powder

Abstract

The application discloses a kind of SiC powder high-efficiency purification method, the present application relates to the purification field of SiC powder, comprising the following operating steps: S1: the following materials and equipment are prepared for purification;S2: the weighing and placement of silicon carbide powder;S3: the laying of graphite hard felt;S4: temperature measurement;S5: the purification treatment of silicon carbide powder;S7: the weighing and quality loss detection of silicon carbide powder;S8: the GDMS characterization of silicon carbide powder.The SiC powder high-efficiency purification method of the application, the loss amount of powder after the purification of silicon carbide powder can be obtained by weighing and calculating, the impurity removal effect is directly displayed by GDMS detection after the purification of silicon carbide powder, and the heating efficiency of the method is high, the heat preservation effect is good, the temperature measurement operation is convenient, only the heating temperature and heating time need to be changed, the process is simple, the purification effect is displayed by GDMS, and the purification effect is intuitive.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of SiC powder purification, in particular to a method for high-efficiency purification of SiC powder. BACKGROUND

[0002] As a representative of wide-gap semiconductor material, silicon carbide has been the focus of research due to its excellent performance. Single crystal silicon carbide has excellent physical and chemical properties and is an ideal substrate material for manufacturing high-power, high-temperature, high-frequency, and radiation-resistant devices. However, the application of silicon carbide substrate material has been limited due to the difficulty in obtaining high-quality silicon carbide single crystals. Therefore, it is very important to improve the quality of silicon carbide crystals, which is influenced by many factors, including the strict requirements for the purity of raw materials in the preparation process. Silicon carbide powder is the raw material for preparing single crystal silicon carbide, and the impurity content will seriously affect the quality of the single crystal, including the existence of metal elements such as aluminum and iron, which will lead to the proliferation of dislocation defects. If industrial high-purity silicon carbide powder is directly used as the raw material for single crystal growth, the impurities in the raw material will deposit into the single crystal to form various defects, which will damage the integrity of the crystal lattice and affect the quality and properties of the crystal lattice, ultimately leading to the failure of subsequent single crystal growth. Therefore, it is very important to purify the silicon carbide powder source before single crystal growth.

[0003] Therefore, it is necessary to solve the problem of high impurity content in industrial silicon carbide powder, the problem of serious loss of silicon carbide raw material in existing purification technology, and the problem of complex silicon carbide powder purification process.

[0004] Therefore, it is necessary to propose a method for high-efficiency purification of SiC powder to solve the above problems. SUMMARY

[0005] The main purpose of the present application is to provide a method for high-efficiency purification of SiC powder, which can effectively solve the problems in the background art.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0007] A method for high-efficiency purification of SiC powder, comprising the following operation methods:

[0008] S1: Prepare the following materials and equipment for purification: the materials include a thermometer, a coil, a temperature measurement window, a quartz tube, a crucible, a graphite hard felt, silicon carbide powder, and a bottom support;

[0009] S2: Take out the crucible, weigh the silicon carbide powder, and evenly lay the silicon carbide powder in the inner cavity of the crucible;

[0010] S3: Place the crucible containing the silicon carbide powder into the quartz tube, and place the graphite hard felt around the crucible and the bottom support at the bottom of the crucible when placing.

[0011] S4: The thermometer measures the temperature through the central reserved temperature measurement window above the crucible;

[0012] S5: The silicon carbide powder is heated to 1000 DEG C and kept for 3 hours in a vacuum state;

[0013] S6: At the end of the heat preservation of the step S5, argon is passed to keep the internal gas pressure of the crucible at 30-50 Kpa, and then the temperature inside the crucible is increased to 1500 DEG C and kept for 5 hours;

[0014] S7: After the step S6 is finished, the temperature inside the crucible is increased to 2000-2200 DEG C and kept for 15-30 hours;

[0015] S8: In the last stage, after the heat preservation stage, the temperature is gradually reduced to room temperature;

[0016] S9: The purified silicon carbide powder is taken out, weighed, observed in shape, and detected in quality loss;

[0017] S10: The purified silicon carbide powder is taken out for GDMS characterization, and the content of iron, aluminum, beryllium, titanium, sodium and cobalt in the purified silicon carbide powder is detected.

[0018] Preferably, in the step S1, the bottom support is fixedly connected to the bottom of the crucible, the temperature measurement window is fixedly connected to the top of the crucible, the size of the temperature measurement window is matched with the size of the thermometer, the crucible is placed in the inner cavity of the quartz tube, the coil is wound on the outer wall of the quartz tube, the graphite hard felt is placed in the inner cavity of the quartz tube, and the graphite hard felt is wrapped on the outer wall of the crucible.

[0019] Preferably, in the step S1, the mass of the silicon carbide powder is 1000 g.

[0020] Beneficial effects

[0021] Compared with the prior art, the present application provides a method for efficiently purifying SiC powder, which has the following beneficial effects:

[0022] 1. The method for efficiently purifying SiC powder, the method has the advantages of high heating efficiency by using a self-designed intermediate frequency induction heating furnace, the graphite crucible can effectively prevent other impurities in the environment from being polluted in the inert gas, the heating furnace is operated in a closed box to reduce the possibility of danger generated in the purification process, a large amount of impurities in the industrial silicon carbide powder is volatilized, the purification effect is good, the impurities are removed while reducing the loss of silicon carbide powder, the temperature of the crucible can be directly measured through the temperature measurement window, the purification process only needs to change the heating time and heating temperature, the process is simple, the loss of the silicon carbide powder after purification can be obtained by weighing and calculating, the impurity removal effect is directly displayed by GDMS detection after the silicon carbide powder is purified, the method has high heating efficiency, good heat preservation effect and convenient temperature measurement operation, only the heating temperature and heating time need to be changed, the process is simple, the purification effect is displayed by GDMS, and the purification effect is intuitive. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a structural schematic diagram of the raw material purification equipment of the application;

[0024] Figure 2 is an appearance diagram of the industrial silicon carbide powder before purification in the application;

[0025] Figure 3 is an appearance diagram of the silicon carbide powder after purification in embodiment one of the application;

[0026] Figure 4 is an appearance diagram of the silicon carbide powder after purification in embodiment two of the application.

[0027] In the figure: thermometer, (01); coil, (02); temperature measurement window, (03); quartz tube, (04); crucible, (05); graphite hard felt, (06); silicon carbide powder, (07); bottom support, (08). DETAILED DESCRIPTION

[0028] In order to make the technical means, creative features, purposes and effects of the application easy to understand, the application will be further described below in combination with specific embodiments.

[0029] As shown in Figure 1 , a method for efficiently purifying SiC powder, comprising the following operation methods:

[0030] S1: Prepare the following materials and equipment for purification: materials include thermometer 01, coil 02, temperature measurement window 03, quartz tube 04, crucible 05, graphite hard felt 06, silicon carbide powder 07, bottom support 08, which is fixedly connected to the bottom of the crucible 05, the temperature measurement window 03 is fixedly connected to the top of the crucible 05, the size of the temperature measurement window 03 is matched with the size of the thermometer 01, the crucible 05 is placed in the inner cavity of the quartz tube 04, the coil 02 is wound on the outer wall of the quartz tube 04, and the graphite hard felt 06 is placed in the inner cavity of the quartz tube 04, and the graphite hard felt 06 is wrapped around the outer wall of the crucible 05.

[0031] S2: Take out the crucible 05, weigh the silicon carbide powder 07, the mass of the silicon carbide powder 07 is 1000g, and the silicon carbide powder 07 is evenly laid in the inner cavity of the crucible 05.

[0032] S3: Put the crucible 05 filled with silicon carbide powder 07 into the quartz tube 04, and place the graphite hard felt 06 around the crucible 05 and the bottom support 08 at the bottom of the crucible 05.

[0033] S4: The thermometer 01 measures the temperature through the centrally reserved temperature measurement window 03 above the crucible 05.

[0034] S5: Heat the silicon carbide powder 07 to 1000℃ and keep it in a vacuum state for 3 hours.

[0035] S6: At the end of the heat preservation of S5, pass argon gas to keep the internal gas pressure of the crucible 05 at 30-50Kpa, then increase the temperature inside the crucible 05 to 1500℃ and keep it for 5 hours.

[0036] S7: After the end of S6, increase the temperature inside the crucible 05 to 2000-2200℃ and keep it for 15-30 hours.

[0037] S8: In the last stage, after the heat preservation stage, gradually reduce the temperature to room temperature.

[0038] S9: Take out the purified silicon carbide powder 07, weigh it, observe its appearance, and detect its mass loss.

[0039] S10: Take the purified silicon carbide powder 07 for GDMS characterization, and detect the content of iron, aluminum, beryllium, titanium, sodium and cobalt in the purified silicon carbide powder 07. Specific embodiment one:

[0041] A method for efficiently purifying SiC powder, comprising the following operation methods:

[0042] S1: Prepare the following materials and equipment for purification: materials include thermometer 01, coil 02, temperature measurement window 03, quartz tube 04, crucible 05, graphite hard felt 06, silicon carbide powder 07, bottom support 08, which is fixedly connected to the bottom of the crucible 05, the temperature measurement window 03 is fixedly connected to the top of the crucible 05, the size of the temperature measurement window 03 is matched with the size of the thermometer 01, the crucible 05 is placed in the inner cavity of the quartz tube 04, the coil 02 is wound on the outer wall of the quartz tube 04, and the graphite hard felt 06 is placed in the inner cavity of the quartz tube 04, and the graphite hard felt 06 is wrapped around the outer wall of the crucible 05.

[0043] S2: Take out the crucible 05, weigh the silicon carbide powder 07, the mass of the silicon carbide powder 07 is 1000g, and evenly lay the silicon carbide powder 07 in the inner cavity of the crucible 05.

[0044] S3: Put the crucible 05 filled with silicon carbide powder 07 into the quartz tube 04, and place the graphite hard felt 06 around the crucible 05 and the bottom support 08 at the bottom of the crucible 05.

[0045] S4: The thermometer 01 measures the temperature through the centrally reserved temperature measurement window 03 above the crucible 05.

[0046] S5: Heat the silicon carbide powder 07 to 1000℃ and keep it in a vacuum state for 3 hours.

[0047] S6: At the end of the heat preservation of S5, pass argon gas to keep the internal pressure of the crucible 05 at 30-50Kpa, then increase the temperature inside the crucible 05 to 1500℃ and keep it for 5 hours.

[0048] S7: After the end of S6, increase the temperature inside the crucible 05 to 2200℃ and keep it for 30 hours.

[0049] S8: In the last stage, after the heat preservation stage, gradually reduce the temperature to room temperature.

[0050] S9: Take out the purified silicon carbide powder 07, weigh it, observe its appearance, and detect its mass loss, the mass loss results are shown in Table 1, and the appearance change is shown in Table 1. Figure 3 As shown in Table 1, after the purification process of Example 1, the mass loss of the silicon carbide powder is about 2%.

[0051] S10: The purified silicon carbide powder 07 is taken for GDMS characterization, and the content of iron, aluminum, beryllium, titanium, sodium and cobalt in the purified silicon carbide powder 07 is detected. As shown in Table 2, the contents of iron, aluminum, beryllium, titanium, sodium and cobalt in the industrial silicon carbide powder obtained by the application are 120 ppm, 150 ppm, 20 ppm, 35 ppm, 50 ppm and 30 ppm respectively, and the contents of iron, aluminum, beryllium, titanium, sodium and cobalt in the silicon carbide powder purified by the process of Example 1 are 50 ppm, 22 ppm, <0.01 ppm, <0.01 ppm, 0.22 ppm and <0.01 ppm respectively. Specific embodiment two:

[0053] A method for efficiently purifying SiC powder, comprising the following operation methods:

[0054] S1: Prepare the following materials and equipment for purification: materials include thermometer 01, coil 02, temperature measurement window 03, quartz tube 04, crucible 05, graphite hard felt 06, silicon carbide powder 07, and bottom support 08 fixedly connected to the bottom of the crucible 05, the temperature measurement window 03 is fixedly connected to the top of the crucible 05, the size of the temperature measurement window 03 is matched with the size of the thermometer 01, the crucible 05 is placed in the inner cavity of the quartz tube 04, the coil 02 is wound around the outer wall of the quartz tube 04, and the graphite hard felt 06 is placed in the inner cavity of the quartz tube 04, and the graphite hard felt 06 is wrapped around the outer wall of the crucible 05.

[0055] S2: Take out the crucible 05, weigh the silicon carbide powder 07, and evenly lay the silicon carbide powder 07 in the inner cavity of the crucible 05.

[0056] S3: Put the crucible 05 with the silicon carbide powder 07 into the quartz tube 04, and place the graphite hard felt 06 around the crucible 05 and the bottom support 08 at the bottom of the crucible 05.

[0057] S4: The thermometer 01 measures the temperature through the centrally reserved temperature measurement window 03 above the crucible 05.

[0058] S5: Heat the silicon carbide powder 07 to 1000℃ and maintain for 3 hours in a vacuum state.

[0059] S6: At the end of the heat preservation of S5, pass argon gas to keep the internal gas pressure of the crucible 05 at 30-50 Kpa, and then increase the temperature in the crucible 05 to 1500℃ and maintain for 5 hours.

[0060] S7: After the end of S6, increase the temperature in the crucible 05 to 2000℃ and maintain for 15 hours.

[0061] S8: In the last stage, the temperature gradually decreases to room temperature after the heat preservation stage.

[0062] S9: The purified silicon carbide powder 07 is taken out, weighed, observed for shape, and detected for mass loss. The mass loss results are shown in Table 1, and the shape change is shown in Table 2. Figure 4 As shown in Table 1, the mass loss of the silicon carbide powder after purification by the process of Example 2 is about 4.3%.

[0063] S10: The purified silicon carbide powder 07 is subjected to GDMS characterization, and the content of iron, aluminum, beryllium, titanium, sodium, and cobalt in the purified silicon carbide powder 07 is detected. As shown in Table 2, the contents of iron, aluminum, beryllium, titanium, sodium, and cobalt in the industrial silicon carbide powder obtained by the present application are 120 ppm, 150 ppm, 20 ppm, 35 ppm, 50 ppm, and 30 ppm, respectively. After purification by the process of Example 1, the contents of iron, aluminum, beryllium, titanium, sodium, and cobalt in the silicon carbide powder are <5 ppm, <5 ppm, <0.01 ppm, <0.01 ppm, 0.22 ppm, and <0.01 ppm, respectively.

[0064] Table 1: Mass loss results of the purified silicon carbide powder in Specific Embodiment 1 and Specific Embodiment 2:

[0065]

[0066]

[0067] Table 2: GDMS detection results of the silicon carbide powder before and after purification:

[0068]

[0069] The present method uses a self-designed intermediate frequency induction heating furnace, which has the advantage of high heating efficiency. The graphite crucible 05 can effectively prevent other impurities in the environment from being contaminated in the inert gas. The heating furnace operates in a closed box, reducing the possibility of danger during the purification process. The impurities in the industrial silicon carbide powder are largely volatilized, resulting in good purification effect. The removal of impurities reduces the loss of silicon carbide powder 07. The temperature of the crucible 05 can be directly measured through the temperature measurement window 3. The purification process only needs to change the heating time and heating temperature, and the process is simple. The loss of the purified silicon carbide powder 07 can be obtained by weighing and calculating. After purification, the silicon carbide powder 07 is detected by GDMS to directly show the impurity removal effect. At the same time, this method has high heating efficiency, good heat preservation effect, and convenient temperature measurement operation. Only the heating temperature and heating time need to be changed, and the process is simple. The purification effect is shown by GDMS, and the purification effect is intuitive.

[0070] The above shows and describes the basic principles and main features of the present application and the advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above embodiments, and the above embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for efficient purification of SiC powder, characterized in that: The following operating methods are included: S1: Prepare the following materials and equipment for purification: The materials include a thermometer (01), a coil (02), a temperature measuring window (03), a quartz tube (04), a crucible (05), a graphite felt (06), silicon carbide powder (07), and a bottom support (08); S2: Take out the crucible (05), weigh the silicon carbide powder (07), and spread the silicon carbide powder (07) evenly in the inner cavity of the crucible (05); S3: Place the crucible (05) containing silicon carbide powder (07) into the quartz tube (04). When placing the crucible (05), place graphite hard felt (06) around the crucible (05) and place a bottom support (08) at the bottom of the crucible (05). S4: The thermometer (01) measures the temperature through the temperature measurement window (03) reserved in the center above the crucible (05); S5: Heat the silicon carbide powder (07) to 1000°C and continue in a vacuum for 3 hours; S6: When the heat preservation in step S5 is finished, argon gas is introduced to keep the internal pressure of the crucible (05) at 30-50 kPa, and then the internal temperature of the crucible (05) is raised to 1500℃ and maintained for 5 hours. S7: After step S6 is completed, raise the temperature inside the crucible (05) to 2000-2200℃ and continue for 15-30 hours; S8: In the final stage, after the heat preservation stage, the temperature is gradually reduced to room temperature; S9: Take out the purified silicon carbide powder (07), weigh it, observe its appearance, and detect its mass loss; S10: The purified silicon carbide powder (07) was characterized by GDMS, and the contents of iron, aluminum, beryllium, titanium, sodium and cobalt in the purified silicon carbide powder (07) were detected. In step S1, the bottom support (08) is fixedly connected to the bottom of the crucible (05), the temperature measurement window (03) is fixedly connected to the top of the crucible (05), the size of the temperature measurement window (03) is adapted to the size of the thermometer (01), the crucible (05) is placed in the inner cavity of the quartz tube (04), the coil (02) is wound around the outer wall of the quartz tube (04), the graphite hard felt (06) is placed in the inner cavity of the quartz tube (04), and the graphite hard felt (06) is wrapped around the outer wall of the crucible (05); In step S1, the mass of silicon carbide powder (07) is 1000g.

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