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WO2017183747A1 - Creuset destiné à une solution de croissance et procédé de croissance d'une solution à l'intérieur d'un creuset - Google Patents

Creuset destiné à une solution de croissance et procédé de croissance d'une solution à l'intérieur d'un creuset Download PDF

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Publication number
WO2017183747A1
WO2017183747A1 PCT/KR2016/004150 KR2016004150W WO2017183747A1 WO 2017183747 A1 WO2017183747 A1 WO 2017183747A1 KR 2016004150 W KR2016004150 W KR 2016004150W WO 2017183747 A1 WO2017183747 A1 WO 2017183747A1
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Prior art keywords
crucible
melt
block
sic
graphite
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English (en)
Korean (ko)
Inventor
서원선
정성민
이명현
김영희
윤지영
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Korea Institute of Ceramic Engineering and Technology KICET
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Korea Institute of Ceramic Engineering and Technology KICET
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Priority to PCT/KR2016/004150 priority Critical patent/WO2017183747A1/fr
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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
    • C30B15/10—Crucibles or containers for supporting the melt
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/10—Inorganic compounds or compositions
    • C30B29/36—Carbides

Definitions

  • the present invention relates to a crucible for solution growth and a solution growth method in a crucible, and more particularly, to a crucible for growing a single component or a compound crystal by reacting with a crucible component, wherein the melt or compound of the single component is contained in the crucible.
  • the melt of some components constituting the is accommodated, the melt is to react with the inner wall of the crucible, the inner wall of the crucible provides a crucible for solution growth, characterized in that the roughness is given.
  • SiC which is a compound of silicon (Si) and carbon (C)
  • Si is a material in which Si is covalently bonded to C.
  • Si has excellent mechanical properties due to strong covalent bonds, so it has high durability such as abrasives, automobile brakes, clutches, and bulletproof vests. It has been widely used as the required structural material.
  • SiC can be used in electronic fields such as light emitting diodes (LEDs) and radio detectors, and thus can be utilized in semiconductor electronic fields that require high temperature or high voltage.
  • LEDs light emitting diodes
  • SiC is a representative wide bandgap material, and its application as a next-generation power semiconductor material has recently moved away from the step of being mainly used as a structural material.
  • SiC single crystal substrates are attracting attention as a material that can replace the Si single crystal substrates that have been conventionally used in terms of high efficiency of power converters, use of extreme environments, and the like.
  • SiC single crystal manufacturing methods include physical vapor transport (PVT), which is already widely used, and high temperature chemical vapor deposition (PVT) and solution growth.
  • PVT physical vapor transport
  • PVD high temperature chemical vapor deposition
  • solution growth method is a technique that has been in the spotlight recently because it can grow SiC by a method similar to the Czochralski liquid growth method widely used in Si or sapphire.
  • SiC is a method of growing single crystal in a solution different from solid phase.
  • the concentration of C dissolved in the Si melt governs the growth rate of the crystal.
  • C is supplied from a graphite crucible which is a heating element and serves as a container for Si melt. Therefore, the design and process control of the graphite crucible are very important experimental elements in SiC solution growth.
  • the inventor has devised the Republic of Korea Patent No. 1549597 "Method for producing silicon carbide single crystal using a crucible coated with silicon carbide".
  • the above patent discloses a technique for coating silicon carbide on a carbon crucible and accommodating Si melt therein to grow silicon carbide single crystals from the reaction of the Si melt with the inner wall of the carbon crucible.
  • the registered patent is limited to increase the SiC single crystal growth rate only by the graphite crucible and the Si melt system.
  • the silicon carbide layer having the same composition as that of the single crystal to be grown on the graphite crucible is prepared in advance. It is a technology that increases the growth rate of silicon carbide single crystal by forming.
  • the technique presented in the above patent has a great meaning of presenting the time of considering the graphite crucible as a raw material of SiC, there is no consideration about the surface treatment and single crystal growth rate of the inner wall of the crucible and the surface of the silicon carbide layer coated thereon. .
  • the chemical reaction is activated, while the inside of the graphite crucible is generally smooth. Therefore, the growth rate of silicon carbide can be further improved because the silicon carbide growth is still limited in speed. Raise the possibility of a solution.
  • the present invention has been made to solve the above problems of the prior art, the present invention provides a roughness to the inner surface of the crucible to increase the dissolution rate compared to the crucible of the smooth inner surface to increase the growth rate of single component or compound crystals It is an object of the present invention to provide a solution growth crucible having a block capable of making it possible and a solution growth method in the crucible.
  • the present invention blocks the rapid erosion effect of the crucible generated during the growth process of the crystal by charging a block having a surface roughness inside the crucible instead of providing a roughness to the inner surface of the crucible or at the same time as a roughness. It is another object of the present invention to provide a solution growth crucible and a solution growth method in the crucible which can be dispersed by erosion of the crucible to prevent rapid collapse of the crucible.
  • the present invention relates to a crucible for growing monocomponent or compound crystals by reacting with a crucible component, wherein the melt of the single component or a melt of some components constituting the compound is contained in the crucible.
  • the melt is to react with the inner wall of the crucible, the inner wall of the crucible provides a crucible for solution growth, characterized in that the roughness is given.
  • the single crystal of the compound crystal is a SiC single crystal
  • the crucible is a graphite crucible
  • the melt of some components of the compound is a Si melt.
  • the roughness preferably has a surface roughness of 10 to 30 ⁇ m.
  • a block of the same component as the crucible is accommodated in the crucible.
  • the block is preferably formed integrally with the crucible, or is housed separately from the crucible.
  • the block is preferably given a roughness on its surface.
  • the roughness applied to the surface of the block preferably has a surface roughness of 10 to 30 ⁇ m.
  • the present invention also provides a crucible for growing a single component or a compound crystal by reacting with a crucible component, wherein a block of the same component as that of the crucible is provided, and in the crucible a part of a component or component of the single component melt
  • the melt is accommodated and the melt reacts with the inner wall of the crucible and the block, wherein the surface of the block is formed with a rougher surface than the inner wall of the crucible so that the melt is more active with the surface of the block than the inner wall of the crucible.
  • It provides a crucible for solution growth, characterized in that it is induced to react.
  • the single crystal of the said compound crystal is a SiC single crystal
  • the said crucible is a graphite crucible
  • the melt of some components of the compound is a Si melt
  • the block is a graphite block.
  • the roughness applied to the surface of the block preferably has a surface roughness of 10 to 30 ⁇ m.
  • the present invention also provides a solution growth method using a crucible for growing a single component or compound crystal in a solution, the method comprising: providing a roughness to an inner wall of the crucible; Receiving a melt of the single component or some component of the compound in the crucible; It provides a solution growth method in the crucible comprising the; comprising the step of causing the melt and the inner wall of the crucible to grow a single component or compound crystals.
  • the single crystal of the compound crystal is a SiC single crystal
  • the crucible is a graphite crucible
  • the melt of some components of the compound is a Si melt.
  • the roughness preferably has a surface roughness of 10 to 30 ⁇ m.
  • the present invention is a solution growth method using a crucible for growing a single component or compound crystal in a solution, the same component as the crucible inside the crucible, containing a block having a surface rougher than the inner wall of the crucible step; Receiving a melt of the single component or some component of the compound in the crucible; Inducing the melt to react with the inner wall of the crucible and the block to grow single component or compound crystals, wherein the melt reacts more actively with the block than the inner wall of the crucible. It provides a solution growth method in the crucible.
  • the single crystal of the said compound crystal is a SiC single crystal
  • the said crucible is a graphite crucible
  • the melt of some components of the compound is a Si melt
  • the block is a graphite block.
  • the roughness of the block preferably has a surface roughness of 10 ⁇ 30 ⁇ m.
  • the process of processing the inner surface of the crucible which is relatively difficult compared to the block, can be omitted by using the same component as the crucible with the roughness instead of providing the roughness to the inner surface of the crucible as needed. The effect is expected.
  • FIG. 1 is a schematic diagram showing a TSSG growth reactor showing a tendency to decrease in temperature as it progresses upward.
  • FIG. 2 is a flowchart showing a simulation design method for considering the silicon carbide growth behavior of the present invention.
  • FIG. 3 is a schematic diagram showing a TSSG reactor for silicon carbide growth according to an embodiment of the present invention.
  • Figure 4 is a schematic diagram showing the boundary conditions of the Si melt and crucible for heat transfer analysis and fluid analysis of the graphite crucible according to an embodiment of the present invention.
  • FIG. 5 is a planar photograph and a front schematic view showing a graphite block according to an embodiment of the present invention.
  • (a) shows a smooth surface
  • (b) shows a rough surface, respectively.
  • Figure 6 is a crucible and block arrangement diagram prepared for the surface microstructure analysis of the graphite block according to an embodiment of the present invention.
  • Figure 7 is a graph showing the overall temperature gradient of the reaction vessel by the electromagnetic induction and heat transfer to the graphite crucible according to an embodiment of the present invention.
  • FIG. 8 is a graph showing the temperature distribution of the Si melt when the temperature of the surface of the Si melt according to one embodiment of the present invention is 1700 ° C.
  • FIG. 9 is a graph showing the concentration of carbon dissolved in a Si melt together with a flow pattern in the melt according to one embodiment of the present invention.
  • FIG. 9 is a schematic diagram showing the SiC crystal growth mechanism constituting the dissolution and recrystallization step according to an embodiment of the present invention.
  • FIG. 10 is a SEM photograph and a schematic view of grown interlayer shapes of SiC single crystals according to an embodiment of the present invention.
  • FIG. 11 illustrates a surface microstructure of a graphite block having a smooth surface and a rough surface according to an embodiment of the present invention.
  • FIG. 12 is a photograph showing a cross section of the graphite surface of the rough surface according to an embodiment of the present invention with the graphite block of the smooth surface.
  • 13 is a graph showing the change in thickness of the penetration layer according to the temperature function measured by an embodiment of the present invention.
  • FIG. 14 is a graph showing the thickness change of the intermediate layer according to the temperature function measured by an embodiment of the present invention.
  • 15 is a schematic view showing the thickness of the SiC intermediate layer of the graphite block having a rough surface in comparison with the graphite block having a smooth surface according to an embodiment of the present invention.
  • 16 is a graph showing the average thickness of SiC single crystals grown at different temperatures according to an embodiment of the present invention.
  • 17 is a graph showing the change of the SiC intermediate layer according to the specific surface area and the growth rate according to an embodiment of the present invention.
  • FIG. 18 is an X-ray graph illustrating growth of 4H-SiC at 1700 ° C. using graphite blocks having different surface roughnesses and confirming their crystal phases according to an embodiment of the present invention.
  • 19 is a graph showing an X-ray rocking curve of 4H-SiC before and after growth at 1700 ° C using a graphite block having a smooth surface according to one embodiment of the present invention.
  • 20 is a graph showing an X-ray rocking curve of 4H-SiC before and after growth at 1700 ° C using a graphite block having a rough surface according to one embodiment of the present invention.
  • the present invention can increase the growth rate of a single component or compound crystal in a crucible having an inner surface exhibiting a certain roughness compared to a crucible having a 'smooth' inner surface.
  • the crucible erodes over time as it dissolves in the melt of a single component or a part of the compound, the crucible may be collapsed during the growth of the single crystal.
  • a block given with a separate surface roughness is charged into the crucible. It is characterized by the fact that the dissolution of the corresponding constituents in the and blocks occurs mainly in the blocks, thereby delaying the crucible collapse and allowing crystal growth for a long time.
  • the SiC single crystal in the compound crystal was grown as an example.
  • a graphite crucible and a graphite block were used, and a reaction melt for reacting with the crucible and / or the block used a Si melt.
  • the growth of SiC single crystals will be described.
  • the solution growth crucible and solution growth method of the present invention are not used only for the growth of SiC single crystals, but may be used for the growth of other single components, single crystals of a compound, and polycrystals. Yes, it will be obvious.
  • an SiC coating layer may be further formed on the inner wall of the graphite crucible in order to increase the reaction rate with the Si melt. From this, the SiC single crystal may be grown by reacting the Si melt with the SiC coating layer.
  • SiC is a compound of Si and C. It is a compound composed of covalent bonds and partial ionic bonds, and each atom is bonded to four other elements in a tetrahedral structure. SiC is a stoichiometric compound and it is known that there are more than 200 crystal polymorphs of cubic, hexagonal, and rhombohedral depending on the crystalline structure. These polymorphic forms have different names depending on the crystal structure and the stacking period. The numbers in the front (3, 4, 6, 15, etc.) mean the stacking period, and the letters (C, H, R) in the back mean the crystal structure.
  • Table 2 shows the characteristics of the polymorphs mainly applied.
  • SiC as a semiconductor material has a relatively high dielectric breakdown voltage, high thermal conductivity, and high electron saturation rate compared to Si, and thus, SiC is a suitable material for replacing Si devices.
  • the high dielectric breakdown voltage of SiC enables the implementation of monopolar devices in the voltage range above 1 kV. This is about 10 times higher than that of Si, which means that the same device can be manufactured with a thickness of 1/10 times the SiC thin film and 10 times the doping concentration, and theoretically 100 times the gain in the on state of the monopolar device. do. In applications in power circuits, switching losses can be relatively reduced compared to bipolar devices using fast switching speeds.
  • the heat generated in the power device can easily diffuse the heat generated from the on-state resistance and switching losses due to the high thermal conductivity of the SiC can improve the performance of the device.
  • the SiC power device is suitable for a hybrid electric vehicle (EV) / electric vehicle (EV) because it can operate in a high thermal environment based on high thermal conductivity and thermal safety and can reduce overall cooling system.
  • SiC crystals grown by PVT method can grow faster than 1mm / h and can grow larger than the size of seed crystals, but it is difficult to grow high quality single crystals, requires high temperature conditions, and cannot grow continuously in closed system.
  • HTCVD High Temperature Chemical Vapor Deposition
  • HTCVD High Temperature Chemical Vapor Deposition
  • HCVD halide chemical vapor deposition
  • SiC is not possible to achieve congruent melt growth in which the stoichiometric ratios are consistent, and research is being conducted to grow SiC from non-stoichiometric solutions. Since the solution growth method is grown at a relatively low process temperature, it is easy to grow a high quality single crystal having a low dislocation density, and thus, a lot of attention began in the 2000s.
  • the method of growing a single crystal from a liquid phase is widely used in various materials such as silicon and sapphire.
  • SiC in order to grow a single crystal from a stoichiometric solution of Si and C, a pressure of 100,000 atm and a temperature of 3200 ° C. or more are required. Therefore, industrial process development is almost impossible. Therefore, in the case of SiC, a physical vapor transport method for obtaining single crystals by sublimation of SiC powder and recrystallization has been widely studied and has become a commercialization technology.
  • solution growth method has recently attracted high interest because it is easy to grow high quality single crystals having low dislocation density.
  • the solution growth method has the advantage that single crystal growth is possible at a temperature lower than that of the general SiC single crystal growth method, and it can reduce point defects occurring during the growth process and unwanted impurities. Can be easily suppressed and stress generated during cooling to room temperature after growth can be reduced, so control of crystal polymorphism is easy and high quality single crystal growth is possible.
  • SiC solution growth method is a method of growing SiC single crystal from Si melt with C dissolved, but the problem of C solubility in Si melt is very small, ease of formation of impurities by parasitic phase formation, and low growth rate compared to other growth methods. Therefore, it is not used for bulk crystal growth of SiC single crystal, but has been used for epitaxy thin film growth process.
  • Recently, in order to grow single crystals from Si melts studies have been conducted to increase the solubility of C by introducing high temperature, high pressure, or flux. In order to increase the solubility of C in the Si melt, a process using three-component and four-component systems using various metals is being progressed. Sumitomo Metal has reported the development of high quality SiC single crystal using Si-Ti-C melt, and Toyota announced that it has grown high quality SiC single crystal using Si-Cr-C melt.
  • the schematic diagram of the TSSG method crystal growth furnace is shown in FIG.
  • Seed crystals are mounted on graphite rods and charged to the growth furnace. Seed crystals and crucibles can be rotated in the same direction or in opposite directions. The most common method is to rotate only seed crystals at a speed of 10 to 20 rpm.
  • the TSSG method is promising in that the technology accumulated in the development of these materials can be applied relatively easily because the crystal is grown in a manner similar to that of Si or sapphire growth.
  • a method of increasing the growth rate by applying the accelerated crucible rotation technique (ACRT) is proposed. This method controls the seed crystal and the crucible's rotation speed and direction of rotation to separate the turbulence in the Si melt. It is a way to get high growth rate by generating. Seed crystals are located in a relatively low temperature range above the Si melt, and the temperature gradient between the seed crystals and the crucible bottom is generally reported to be about 2.0 ° C./mm.
  • SiC single crystal obtained by TSSG method is known to have low dislocation defect density, and also converts defects such as threading screw dislocation (TSD) and threading edge dislocation (TED) to basal plane dislocation (BPD). It is reported that the crystal quality can be improved. It is reported that the conversion behavior of these dislocations in the Si and C planes is different and easier to convert in the rough plane, and that TSD can be converted to extended defect and TED can be converted to BPD. On the rough surface, the transverse growth of the macrostep occurs well, which translates into a translocation.
  • TSD threading screw dislocation
  • TED threading edge dislocation
  • BPD basal plane dislocation
  • the model can be called a multiphysics model.
  • multiphysics modeling the interaction between the physical domains must be included in the process of constructing the model, and this can be mainly considered through the properties and boundary conditions of the analytical domain.
  • Multiphysics problems from a physical point of view can be mathematically approximated to industrial problems using the finite element method (FEM).
  • FEM finite element method
  • COMSOL is a commercial finite element analysis package for multiphysics analysis.
  • Multiphysics 4.3a was used. As described above, the multiphysics analysis was applied to calculate the flow of the crucible and the heat transfer of the fluid by the temperature gradient and the temperature by the induction heating.
  • the measured value used by this invention was applied to the space
  • the data related to the physical properties required for the calculation are shown in Table 4.
  • the physical properties of the graphite crucible and the heat insulating material were used in the experiment, and the pure Si properties were referred to the literature values.
  • the experimental variable data such as the rotation speed of the seed crystal and the frequency of the coil are shown in Table 5.
  • the boundary conditions of Si melt and crucible for heat transfer analysis and fluid analysis of graphite crucibles are shown in FIG. 4.
  • the interface between seed crystal and Si melt was set as sliding wall considering rotation of seed crystal, and the interface between crucible inner wall and Si was designated as no slip condition.
  • the order of analysis was calculated by coupling the flows of fluids by heat transfer after electromagnetic field analysis by induction heating.
  • seed crystals are attached to a graphite shaft and contacted with a Si melt contained in a graphite crucible to grow a SiC single crystal.
  • the graphite crucible is a heating element and a container for the melt, and also serves as a C source, so it is a very important factor.
  • a cemented carbide 32 mm diameter was used using a machining center (Mynx-650, Daewoo Machinery, Korea).
  • the experiment was carried out using a block obtained by grinding at a rate of application, a rotational speed of 6000 rpm and a feed rate of 5000 mm / min into a graphite crucible. Photographs and shapes of such graphite blocks are shown in FIG. 5.
  • the crucible containing the graphite block used as the comparative group is a crucible used as a heating element of a typical induction furnace, and its size is 40 mm in depth, 38 mm in inner diameter and 10 mm in thickness.
  • the same size and roughness were used.
  • 30.88g of Si chunks of 99.999999% were put into a graphite crucible containing a block having a large surface roughness and a graphite crucible containing a smooth block, and charged into a reactor. At this time, the height of the solvent was measured to 30 ⁇ 35mm.
  • an external crucible having a depth of 90 mm and an inner diameter of 100 mm is used to fix the graphite crucible containing Si to be located at the center.
  • the crucible can be moved during the experiment to make a groove in the inner crucible and the outer crucible to be engaged with each other.
  • the crucible thus prepared was placed inside the coil of the solution growth furnace. And in order to prevent the large amount of Si vaporization generated during the solution growth experiment, the lid of the crucible made of graphite insulation (Rigid felt, Morgan) was covered. Seed crystals used 4H off-axis 4H-SiC crystals grown by PVT. The shape of the seed crystals was circular with a diameter of 10 mm and a thickness of about 300 to 350 ⁇ m, and the seed crystals were attached by applying a thin layer of graphite powder and adhesive to the ends of the graphite rods (ET-15, Ibiden). The growth face of the seed crystal was directed toward the portion where the C face touched the melt, and the C face touched the Si melt in the graphite crucible so that SiC single crystals grew along the face. This is illustrated in FIG. 6.
  • the seed crystals suspended on the crucible immersed the seed crystals into the melt at a certain temperature above the melting temperature of the Si in the graphite crucible. At this time, the seed crystals were rotated at 10 rpm and contacted with the Si melt, and then grown for 1 hour at an Ar gas atmosphere of 715torr, 1600, 1700, and 1800 ° C while maintaining the seed crystal rotation state. After growth, the solution was etched in a solution of 25 ml of 49.5% hydrofluoric acid and 25 ml of 60% nitric acid in a Teflon vessel to remove Si solvent remaining on the seed crystal surface. Etching was performed for 24 to 48 hours until the Si residue on the surface was removed.
  • the center of each crucible was cut into a thickness of about 5 to 10 mm by using a cutter to determine the difference between the seed crystal growth state and the molten state. Smooth cross sections are required to observe the surface of the crucible, and the cut samples were polished using SiC paper and diamond paste of # 400 to # 2000. In addition, the surface shape and cross section of the seed crystals grown using an optical microscope (ME600, Nikon) were observed.
  • EDS Engelgy Dispersive
  • FESEM Field Emission Scanning Electron Microscope, S-2400, Hitachi, Japan
  • X-ray Spectroscopy was used. The sample at this time was cut
  • the crystallization of the graphite crucible was observed by observing the SiC crystal form and quantitative and qualitative analysis by EDS to investigate the amount of C dissolved in the Si melt. It was.
  • Figure 7 shows the overall temperature gradient of the half vessel by electromagnetic induction and heat transfer. It shows that heat is generated inside the graphite crucible and the temperature decreases toward the heat insulating part.
  • the temperature gradient in the crucible where the reaction with Si melt (melt) is small is very small.
  • the temperature gradient between the surface of the melt and the bottom of the crucible is between about 50 and 100 ° C.
  • the experiment was conducted to melt only Si without seed crystals.
  • the pyrometer showed the same temperature gradient as the modeling value.
  • the upper and lower temperature difference in the melt at the target temperature of the Si melt was about 50 ° C., and the temperature gradient was generally about 1 ° C./cm. As shown, the lower temperature of the Si melt was high and the upper was low, which is a condition in which the carbon melted at the lower side due to convection caused by the temperature gradient was easy to mass transfer to the upper seed crystal surface.
  • the fluid flow is called laminar flow
  • the average velocity of the melt by modeling is 0.57m / s, which is calculated by the Reynolds equation.
  • V stir and ⁇ crystal r 0 are the number of revolutions of the seed crystal graphite rod and L is the length of the crucible.
  • the actual fluid velocity is shown in FIG. 10 together with the concentration of carbon dissolved in the Si melt.
  • the concentration of C is calculated using the convective diffusion equation at steady state.
  • D is the carbon diffusion coefficient (1.7 x 10 -8 m 2 ) of the Si melt and u represents the fluid velocity vector.
  • the overall generation mechanism of the SiC single crystal by solution growth as shown by modeling is shown in FIG. 9.
  • the C source of the graphite crucible and the Si melt meet to form a solid SiC layer, which is then reacted with the Si melt to form a C-melted solution.
  • the flow of the fluid has been developed in the form of coming into the center from the outer circumference when viewed on the seed crystal.
  • the inner wall of the graphite crucible may be provided with roughness, and crystals may be grown therefrom.
  • the graphite crucible may be locally drilled after a certain period of time in the process of growing a single crystal according to an increase in the solubility of the inner wall of the graphite crucible.
  • the graphite crucible may be damaged, and eventually collapse rapidly, thereby increasing the durability of the graphite crucible by introducing a graphite block into the graphite crucible, which may be the center of crystal growth of SiC instead of the inner wall of the graphite crucible.
  • a graphite block into the graphite crucible, which may be the center of crystal growth of SiC instead of the inner wall of the graphite crucible.
  • the inventive invention capable of growing.
  • the graphite block may be formed in various shapes such as a polyhedron shape or a sphere or a curved shape, and thus, the graphite block is not particularly limited in shape.
  • SiC single crystals were grown for 1 hour at temperatures of 1600, 1700, and 1800 ° C. using graphite blocks having different roughness inside the graphite crucible.
  • the interface between the graphite block and the Si melt is examined, the interface between Si and the graphite crucible, the surface of the melt in which the seed crystals touch, and the wall part of the crucible are considered.
  • FIG. 10 shows the results of measuring and analyzing FESEM (Field Emission Scanning Electron Microscope, S-2400, Hitachi, Japan) in order to confirm whether the estimated contents are correct. As shown, it was confirmed that the polycrystal between the Si melt and the graphite block was seen, and below that, the graphite block and the layer of other physical properties were visible and formed the same layer as described above.
  • FESEM Field Emission Scanning Electron Microscope, S-2400, Hitachi, Japan
  • the C and Si melts of the graphite crucible react to form an SiC intermediate layer, and the C and Si melts of the intermediate layer combine to form SiC crystals. 12, the following points were confirmed for each reaction site between the graphite crucible and the Si melt.
  • the solid Si melts to form a melt, which penetrates into the porous graphite. Further, at a temperature above the melting point, liquid Si penetrates into the graphite crucible to generate a solid SiC inside the crucible, and thereafter, a reaction between the solid C and the liquid Si occurs at the graphite crucible interface. Even after SiC is produced by Equations 21 and 22, the C and Si melts diffuse through the SiC interlayer to maintain the reaction, and the SiC interlayer continues to thicken. Since the SiC interlayer becomes a direct source of C melting into Si, the thickness of the SiC interlayer influences the growth rate of the seed crystals.
  • the crystal growth rate of the seed crystal phase is determined by the chemical reaction rate of the crystal growth plane and the supersaturation of C in the seed crystal growth plane as the material moves.
  • the supersaturation of C in the crystal growth plane is determined by the solubility of C, It is determined by the mass transfer determined by the fluid flow and the concentration of C dissolved in the Si melt.
  • the SiC intermediate layer is artificially coated and applied.
  • the water solubility in the graphite crucible and / or the inside thereof is roughened by increasing the specific surface area by roughening the surface of the graphite block to activate the chemical reaction of graphite in the low temperature region.
  • the SiC intermediate layer was formed thick and the change of crystal growth behavior was examined.
  • the inner surface of the graphite crucible is Ra ⁇ 3 ⁇ m, and in the present invention, a Ra value larger than this is set.
  • the surface roughness value is smaller than this, it is difficult to expect an improvement in the dissolution rate, and when the surface roughness value is larger than this, Unexpected fluid flow may occur due to wall friction, which may inhibit uniform crystal growth.
  • the surface roughness value has a critical significance in the above range.
  • FIG. 12 shows the results of analyzing the location-specific aspects of the crucible and the Si melt after the solution growth experiment when two graphite blocks having different roughnesses were applied by optical microscope.
  • the thickness of the Si penetrating layer and the SiC interlayer showed a significant difference in the two blocks.
  • the first reaction phenomena according to the formation mechanism of SiC crystals was observed by the crucible by the melting of the Si melt into the crucible to form SiC crystals.
  • FIG. 13 is a graph showing average penetration depths of melting temperatures of Si melts for graphite blocks having smooth and rough surfaces. As the temperature increases, the depth of penetration gradually increases and the rate of increase also increases gradually. Here, the penetration depth in the block of rough surface was about 100 ⁇ 150 ⁇ m thicker than the penetration depth in the block of smooth surface.
  • the thickness change of the SiC intermediate layer with temperature is shown in FIG. 14.
  • the thickness of the SiC intermediate layer increased to 22.5, 26.7, 30.3 ⁇ m for smooth surface graphite blocks, and 30.3, 40.3, 43.3 ⁇ m for rough surface graphite blocks, respectively.
  • graphite blocks with rough surfaces form thick SiC intermediate layers under all conditions.
  • the graphite block on the rough surface is more easily dissolved in carbon than the graphite block on the smooth surface, and therefore, the rough surface processing of graphite is easy to activate the dissolution of carbon.
  • the interval of terrace width becomes large and the step is made uniform.
  • single crystals were grown at 1600, 1700, and 1800 ° C. As the temperature increased, the terraces of the single crystals increased, and when the graphite block of the rough surface was used, the step was more uniformly produced in the case of the smooth surface. Confirmed.
  • the steps were uneven enough to measure the spacing of terrace widths.
  • the spacing of terrace widths increased to 11.7, 46.7, and 93.3 ⁇ m with increasing temperature.
  • the reaction is increased by increasing the C diffusion, so that the steps are uniform and the SiC single crystal growth rate is fast even at low temperatures of 1600, 1700, and 1800 ° C.
  • Figure 16 shows the growth rate after cutting the single crystal cross-section. Although the gap was slightly different from the width of the terrace, it was confirmed that as the temperature increases, the use of graphite blocks with rough surfaces also increased.
  • the correlation between the growth rate and the penetration depth of the Si melt into the graphite block and the SiC layer layer and the specific surface area between the block and the Si melt is shown in FIG. 17.
  • An increase in specific surface area is an increase in reactivity due to surface activation.
  • the shape of the seed crystals may affect the growth of SiC single crystals, but in the present invention, the seed crystals previously applied were not processed by hand and precise shape control was impossible.
  • the previous test result showed relatively high growth rate and uniform step when 1700 °C block is applied. Therefore, SiC using SiC seed crystal with 1.2inch diameter and 1.5mm diameter was processed precisely in this experimental condition. The single crystals were grown, and as a result, the seed crystals which were processed by hand showed a markedly different growth rate.
  • the interval of terrace width was 21.7 ⁇ m on average when using smooth surface block and 129.4 ⁇ m on rough surface, which was about 6 times difference. This resulted in the promotion of SiC crystal growth on rough surfaces.
  • the crystallinity of the crystal can be determined by the half width of the main pick measured in the 2 ⁇ / ⁇ mode.
  • the value of the half width is smaller for the complete single crystal with fewer defects and excellent orientation.
  • the points were measured by dividing the points by A to E.
  • the half widths at points A to E when smooth graphite blocks are used are 28, 23, 71, 18, and 20 arcsec, respectively.
  • the half widths when rough graphite blocks are used are 38, 21, 25, and 37.
  • the maximum half width was obtained at 40 arcsec in both conditions.
  • the present invention theoretically calculates the behavior of Si melt by theoretically calculating the electromagnetic field, buoyancy, thermal capillary, and forced convection which are unknown in actual experiments through multiphysics modeling in SiC single crystal growth by solution growth method.
  • SiC interlayer which acts as a direct raw material of carbon
  • it is thought that precise control of SiC solution growth is possible by applying the point that the carbon solubility can be controlled through the surface shape control of the graphite raw material.
  • the SiC single crystal is grown by separately or separately charging a separate graphite block into the crucible, whether or not the inner wall is processed, the degree of erosion of the inner wall of the crucible is alleviated because the graphite block is consumed for the SiC single crystal growth.

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  • Crystallography & Structural Chemistry (AREA)
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  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)

Abstract

La présente invention concerne un creuset et un procédé permettant la croissance d'une solution à l'intérieur d'un creuset. La présente invention concerne notamment un creuset permettant la croissance d'une solution, le creuset étant conçu pour la croissance d'un composant unique ou d'un composé cristal unique à travers une réaction avec un composant de creuset, le creuset contenant une masse fondue à composant unique ou une masse fondue d'un composant partiel qui constitue un composé, la masse fondue est mise à réagir avec la paroi interne du creuset, et la paroi interne du creuset est dotée d'une rugosité. Selon la présente invention conçue telle que ci-dessus, la surface interne du creuset est dotée d'une rugosité de sorte que, en comparaison avec un creuset présentant une surface interne lisse, le niveau de dissolution est accru, améliorant ainsi la vitesse de croissance du composant unique ou du composé cristal unique. De plus, au lieu de doter la surface interne du creuset d'une rugosité, ou simultanément au fait de doter la surface interne du creuset de la rugosité, un bloc présentant les mêmes composants que celui du creuset présentant une rugosité de surface est introduit dans le creuset, et un cristal unique est alors mis en croissance. En conséquence, l'effet de corrosion rapide du creuset se produisant pendant le procédé de croissance du cristal unique est dispersé par la corrosion du bloc, fournissant ainsi l'effet opérationnel de prévention de l'effondrement rapide du creuset.
PCT/KR2016/004150 2016-04-21 2016-04-21 Creuset destiné à une solution de croissance et procédé de croissance d'une solution à l'intérieur d'un creuset Ceased WO2017183747A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63186775U (fr) * 1987-05-20 1988-11-30
JP2001106600A (ja) * 1999-10-12 2001-04-17 Mitsubishi Cable Ind Ltd 炭化硅素結晶の液相成長方法
KR20130002616A (ko) * 2011-06-29 2013-01-08 에스케이이노베이션 주식회사 탄화규소 단결정 성장 장치 및 그 방법
KR20130007109A (ko) * 2011-06-29 2013-01-18 에스케이이노베이션 주식회사 탄화규소 단결정 성장 장치 및 그 방법
KR20150049300A (ko) * 2013-10-30 2015-05-08 한국세라믹기술원 탄화규소가 코팅된 도가니를 이용한 탄화규소 단결정의 제조방법

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63186775U (fr) * 1987-05-20 1988-11-30
JP2001106600A (ja) * 1999-10-12 2001-04-17 Mitsubishi Cable Ind Ltd 炭化硅素結晶の液相成長方法
KR20130002616A (ko) * 2011-06-29 2013-01-08 에스케이이노베이션 주식회사 탄화규소 단결정 성장 장치 및 그 방법
KR20130007109A (ko) * 2011-06-29 2013-01-18 에스케이이노베이션 주식회사 탄화규소 단결정 성장 장치 및 그 방법
KR20150049300A (ko) * 2013-10-30 2015-05-08 한국세라믹기술원 탄화규소가 코팅된 도가니를 이용한 탄화규소 단결정의 제조방법

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