Enhanced monocrystalline sic production

Abstract

The present invention refers to a method for the production of at least or exactly one monocrystalline SiC solid (20), in particular wafer. The method according to the present invention comprises at least the steps: Providing a PVT reactor (100), wherein the PVT reactor (100) comprises a source material receiving section (118) and a SiC seed solid, in particular SiC seed wafer, holding device (122), Coupling a SiC seed solid (18) to the SiC seed solid holding device (122), wherein the SiC seed solid (18) has a diameter of at least 10cm, Positioning of a ring-shaped SiC source material complex (120) in the source material receiving section (118), wherein the ring-shaped SiC source material complex (120) is formed by one or multiple pieces (140, 142) of SiC source material, Generating gaseous SiC by subliming the SiC source material complex (120), Growing monocrystalline SiC (20) by depositing the gaseous SiC onto the SiC seed solid (18).

Description

[0001] Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT

[0002] Enhanced monocrystalline SIC production

[0003] The present invention refers according to claim 1 to a method for the production of at least or exactly one monocrystalline SiC solid according to claim 16 to a monocrystalline SiC solid of the 4H type, according to claim 23 to a CVD SiC production reactor, according to claims 17, 19 and 24 to methods for producing a ring-shaped SiC source material complex and according to claim 26 to a ring-shaped SiC source material complex.

[0004] PVT processes are used to grow monocrystalline SiC ingots.

[0005] Monocrystalline SiC is very valuable material since it allows the production of very efficient components in the electric device industry furthermore.

[0006] Thus, it exists a very high demand for monocrystalline SiC.

[0007] It is therefore the object of the present invention to provide a possibility to increase the amount of monocrystalline SiC material.

[0008] The before mentioned object is solved by a method for the production of one or at least or exactly one monocrystalline SiC solid, in particular wafer, according to claim 1. Thus, one method according to the present invention comprises preferably at least the steps: Providing a PVT reactor, wherein the PVT reactor comprises a source material receiving section and a SiC seed solid, in particular SiC seed wafer, holding device; Coupling a SiC seed solid to the SiC seed solid holding device, wherein the SiC seed solid has a diameter of at least 10cm and preferably up to 43 cm and highly preferably between 20 cm and 25cm; Positioning of a ring-shaped SiC source material complex in the source material receiving section, wherein the ring-shaped SiC source material complex is formed by one or multiple pieces of SiC source material; Generating gaseous SiC by subliming the SiC source material complex;

[0009] Growing monocrystalline SiC by depositing the gaseous SiC onto the SiC seed solid. The SiC seed solid is preferably a monocrystalline SiC seed wafer, in particular consisting of 4H SiC.

[0010] The PVT reactor is according to a further preferred embodiment of the present invention configured for SiC growth in c-axis direction. Documents PCT / EP2021 / 082331 , EP 0859 87931 and US2012 / 285370 A1 show examples of PVT reactors for growth in c-axis direction.

[0011] The PVT reactor is according to a further preferred embodiment of the present invention configured for SiC growth in a-plane direction. Documents JP 2018083738 A and US Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT

[0012] 2021 / 301418 A1 show examples of PVT reactors for a-plane growth. This embodiment is beneficial since the diameter of monocrystalline wafers or ingots or bouls can be increased in a beneficial manner.

[0013] The before mentioned solution is beneficial since source material transport from the ringshaped SiC source material complex to the SiC seed solid takes place in a highly uniform manner. Crystal growth takes place in an improved manner since the source material availability is very similar over the entire growth face. The improved crystal growth results in less crystal lattice defects and thus less trash.

[0014] Multipe types of crystal lattice defects are known, e.g. Stacking faults “SF” (per unit of length e.g. cm or mm), point defects (per unit of volume e.g. cm3or mm3) and planar defects: Threading Screw Dislocation “TSD”, Basal Plane Dislocation “BPD” and Edge Screw Dislocations “ESD” (per unit of surface square e.g. cm2or mm2). In the context of the present invention, the term “crystal lattice defects” preferably refers exclusively to “planar defects” and “stacking faults” and could therefore also be replaced by the term “planar defects and stacking faults”.

[0015] Further preferred embodiment of the present invention are subject-matter of the following specification parts and / or the further claims.

[0016] The ring-shaped SiC source material complex has according to a preferred embodiment of the present invention an inner diameter, wherein the inner diameter is between 5 / 10 and 10 / 10 of the diameter of the SiC seed solid and preferably between 6 / 10 and 9,5 / 10 of the diameter of the SiC seed solid and most preferably between 6 / 10 and 8 / 10 of the diameter of the SiC seed solid. The ring-shaped SiC source material complex also has an outer diameter, wherein the outer diameter is equal to or larger than 10 / 10 of the diameter of the SiC seed solid and preferably larger than 11 / 10 of the diameter of the SiC seed solid and particular preferably larger than 12 / 10 of the diameter of the SiC seed solid and most preferably between 11 / 10 and 25 / 10 of the diameter of the SiC seed solid, in particular between 12 / 10 and 20 / 10 of the diameter of the SiC seed solid or between 12 / 10 and 15 / 10 of the diameter of the SiC seed solid. This embodiment is beneficial since a line of sight between a section of the surface of the ring-shaped SiC source material complex and the SiC seed solid results by positioning the ring-shaped SiC source material complex in the source material receiving section. It was found by internal research that the improved crystal growth results can be further increased in case the ring-shaped SiC source material complex partially overlaps in vertical direction the SiC seed solid.

[0017] The average density of the SiC of the ring-shaped SiC source material complex is according to a further preferred embodiment of the present invention larger than 3g / cm3and preferably Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT larger than 3,1g / cm3and most preferably larger than 3,2g / cm3. The SIC of the ring-shaped SIC source material complex is preferably free of pores and holes respectively consists of less than 50000 pores and / or holes per m3and preferably less than 5000 pores and / or holes per m3and highly preferably less than 500 pores and / or holes per m3, wherein the total room of all pores and / or holes per m3 is less than 10cm3and preferably less than 1cm3and most preferably less than 0,1cm3. This embodiment is beneficial since the sublimable source material amount is highly uniform along the ring-shaped SIC source material complex.

[0018] The ring-shaped SIC source material complex consists according to a further preferred embodiment of the present invention of less than 50 pieces of SIC source material and preferably of less than 20 pieces of SIC source material and highly preferably of less than 10 pieces of SIC source material and most preferably of less than 5 pieces of SIC source material, e.g. 4 pieces of SIC source material, 3 pieces of SIC source material, 2 pieces of SIC source material or 1 piece of SIC source material. This embodiment is beneficial since a smaller number of pieces leads to a smaller surface size of SIC source material. A smaller surface size leads to a slower sublimation of SIC source material causing a more uniform source material transport and thus less crystal lattice defects. Thus, a surface of a curve enveloping the ring-shaped SIC source material complex defines according to a further preferred embodiment of the present invention a first size, wherein the ring-shaped SiC source material complex forms a surface having a second size, wherein the second size is less than 10 times the first size and preferably less than 5 times the first size and highly preferably less than 3 times the first size and most preferably less than 2 times the first size.

[0019] The ring-shaped SiC source material complex has according to a further preferred embodiment of the present invention a circular outer contour and a circular inner contour. This embodiment is beneficial since it allows use of the ring-shaped SiC source material complex in a circular PVT reactor. Furthermore, the SiC seed solid preferably also comprises a circular contour.

[0020] The ring-shaped SiC source material complex is according to a further preferred embodiment of the present invention positioned inside the source material receiving section in such a manner that a central axis of the ring-shaped SiC source material complex is coaxial to a central axis of the SiC seed solid or the ring-shaped SiC source material complex is positioned inside the source material receiving section in such a manner that a central axis of the ring-shaped SiC source material complex is parallel to a central axis of the SiC seed solid, wherein the central axis of the ring-shaped SiC source material complex and the central axis of the SiC seed solid are in a distance to each other of less than 1 cm and preferably of less than 0,7cm and most preferably of less than 0,5cm. This embodiment is Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT beneficial since a precise positioning inside the PTV reactor causes a uniform material transport from the SIC source material to the SIC seed solid.

[0021] The ring-shaped SIC source material complex has according to a further preferred embodiment of the present invention a minimum mass of 1 kg and preferably of exactly or at least 2kg and highly preferably of exactly or at least 5kg and most preferably of up to 10 or 20kg and consists of SIC of the 3C type or 4H type. This embodiment is beneficial since a large and improved monocrystalline SIC ingot can be produced.

[0022] The SIC source material of the ring-shaped SIC source material complex is according to a further preferred embodiment of the present invention formed on a growth structure, wherein the growth structure comprises at least 80% [mass] carbon or consists of carbon or comprises at least 80% [mass] SIC or consist of SIC, wherein the growth structure surrounds the outer contour of the ring-shaped SIC source material complex or wherein the growth structure is surrounded by the inner contour of the ring-shaped SIC source material complex.

[0023] The SIC source material of the ring-shaped SIC source material complex surrounds according to a further preferred embodiment of the present invention in circumferential direction a growth structure, wherein the growth structure comprises at least 80% [mass] carbon or consists of carbon or comprises at least 80% [mass] SIC or consist of SIC. This embodiment is beneficial since the ring-shaped SIC source material complex can be produced as one free standing piece. Thus, no cutting is required causing less metal contamination or less cleaning efforts. The growth structure is preferably a section of a SIC growth substrate used in a CVD process.

[0024] The monocrystalline SIC solid of the 4H type growth to a volume of more than 400 cm3and preferably to more than or exactly 630 cm3and most preferably to more than or exactly 800 cm3and forms according to a further preferred embodiment of the present invention during growth an average dislocation density per cm2of less than 5000 dislocations per cm2and preferably an average dislocation density per cm2of less than 2000 dislocations per cm2and most preferably an average dislocation density per cm2of less than 1000 dislocations per cm2.

[0025] A gas flow homogenization device is according to a further preferred embodiment of the present invention arranged in the gas flow path between the SIC seed solid holding device and the source material receiving section, wherein the gas flow homogenization device is arranged close to the SIC seed solid holding device than to the source material receiving section. The gas flow homogenization device preferably comprises at least 80% [mass] Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT carbon or consists of carbon or comprises at least 80% [mass] SIC or consist of SIC and has highly preferably a plate like shape and comprises more than 10 holes and preferably more than 50 holes and highly preferably more than 100 holes and more than 200 holes, wherein said holes extend in the direction of the gas flow path. This embodiment is beneficial since uniformity source material gas transport can be further improved.

[0026] The above-mentioned object is also solved by a monocrystalline SIC solid of the 4H type, having a diameter of at least 8 cm and preferably of at least 12 cm and highly preferably of at least 15 cm and most preferably of up to 43 cm and a thickness of at least 0,5cm and preferably of at least 1 cm and highly preferably of at least 2 cm and most preferably of up to 10cm or 20cm or 30cm, wherein the monocrystalline SiC solid having an average dislocation density per cm2of less than 5000 dislocations per cm2and preferably an average dislocation density per cm2of less than 2000 dislocations per cm2and most preferably an average dislocation density per cm2of less than 1000 dislocations per cm2. This solution is beneficial since large and high quality monocrystalline SiC solids can be produced which was not possible before.

[0027] The above-mentioned object is also solved by a method according to claim 17 for the production of a ring-shaped SiC source material complex, in particular for use in the method for the production of one or at least or exactly one monocrystalline SiC solid according to the present invention. Said method preferably comprises at least the steps: Providing a CVD reactor; Arranging at least one and preferably up to 5 and highly preferably up to 10 and most preferably up to 20 SiC growth substrate inside the CVD reactor, wherein the step of arranging at least one SiC growth substrate inside the CVD reactor comprises the steps of connecting a first end of a SiC growth substrate to a first electrode and connecting a second end of the SiC growth substrate to a second electrode; Heating the SiC growth substrate by conducting current from the first electrode to the second electrode or vice versa; Feeding a source gas into the CVD reactor for depositing 3C SiC onto the heated SiC growth substrate, wherein at least one section and preferably multiple sections and most preferably all sections of the SiC growth substrate formed between the first end and the second end extends in a circular direction, wherein the at least one section of the SiC growth substrate extends at least 90° in a circular direction and preferably at least or up to or exactly 180° and particular preferably at least or up to or exactly 270° and most preferably up to or exactly 340°. This solution is beneficial since the SiC growth substrate can be heated by resistive heating and thus allows a very cost-effective production of the ring-shaped SiC source material complex. Documents showing CVD reactors using resistive heating are e.g. WO2022 / 123077, WO2022 / 123078, WO2022 / 123083 or WO2023 / 222785. Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT

[0028] The at least one section of the SIC growth substrate extends according to a further preferred embodiment of the present invention parallel to one plane. Thus, the section of the SiC growth substrate formed between the first end and the second end extending in a circular direction forms a part of a ring and not a spiral.

[0029] The above-mentioned object is also solved by a method according to claim 19 for the production of a ring-shaped SiC source material complex, in particular for use in the method for the production of one or at least or exactly one monocrystalline SiC solid according to the present invention. Said method preferably comprises at least the steps: Providing at least one piece of 4H SiC and preferably multiple pieces of 4H SiC and most preferably up to 100 pieces of 4H SiC; Dividing the at least one piece of 4H SiC in sub-pieces, in particular of the same size, wherein each sub-piece of the majority [mass %] of sub-pieces extends in at least one direction more than 2 cm and preferably more than 5 cm and most preferably up to 10 cm or up to 15 cm; Forming the ring-shaped SiC source material complex by arranging said sub-pieces in a circular manner.

[0030] This solution is beneficial since 4H SiC wafer or 4H SiC ingots considered to be trash due to some major defects can be recycled and thus used to produce new 4H SiC wafer or 4H SiC ingots.

[0031] The above-mentioned object is also solved by a CVD SiC production reactor according to claim 23. Said CVD SiC production reactor comprises preferably at least a process chamber, a gas inlet unit for feeding one feed-medium or multiple feed-mediums into the process chamber for providing a source medium, wherein the gas inlet unit is coupled with at least one feed-medium source, or wherein the gas inlet unit is coupled with at least two feedmedium sources, or wherein the gas inlet unit is coupled with at least or up to three feedmedium sources, a gas outlet unit for removing a vent gas mixture from the reaction space of the process chamber, a holding section for holding one or at least or exactly one SiC growth substrate inside the process chamber in a holding position, wherein the SiC growth substrate has a center axis and a cylindrical shape and a cylindrical through hole, wherein the cylindrical through hole has a through hole center axis, wherein the through hole center axis and the center axis are coaxial, wherein the cylindrical through hole has a through hole diameter and wherein the cylindrical shape has a cylindrical shape outer diameter, wherein the through hole diameter is between 50% and 95% of the cylindrical shape outer diameter, a heating unit for heating a deposition surface of the one or at least or exactly one SiC growth substrate, wherein the heating unit is configured to heat the one or at least or exactly one SiC growth substrate from at least multiple sides, in particularly along the entire circumference of the at least or exactly one SiC growth substrate. Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT

[0032] The above-mentioned object is also solved by a method according to claim 24 for producing a ring-shaped SIC source material complex. Said method comprises preferably at least the steps:

[0033] Providing a CVD SIC production reactor, in particular according claim 21 , holding the one or at least or exactly one SIC growth substrate inside the process chamber in a holding position by means of a holding section, wherein the SIC growth substrate has a center axis and a cylindrical shape and a cylindrical through hole, wherein the cylindrical through hole has a through hole center axis, wherein the through hole center axis and the center axis are coaxial, wherein the cylindrical through hole has a through hole diameter and wherein the cylindrical shape has a cylindrical shape outer diameter, wherein the through hole diameter is between 50% and 95% of the cylindrical shape outer diameter, heating the deposition surface of the one or at least or exactly one SIC growth substrate by means of a heating unit transfer SIC from the source medium on a deposition surface of the one or at least or exactly one SIC growth substrate, wherein the heating unit is configured to heat the one or at least or exactly one SIC growth substrate from at least multiple sides, in particularly along an entire circumference of the one or at least or exactly one SIC growth substrate, in particular by means of heat radiation or induction, feeding one feed-medium or multiple feed-mediums into the process chamber for providing a source medium, growing a ring-shaped SIC source material complex, removing a vent gas mixture from the process chamber.

[0034] This solution is beneficial since a ring-shaped SIC source material complex can be produced allowing the production of improved monocrystalline SIC.

[0035] A gas guide path extends according to a further preferred embodiment of the present invention inside the process chamber, in particular exclusively, along the inside of the SIC growth substrate. This embodiment is beneficial since the gas guide is isolated from the surrounding.

[0036] A gas guide path extends according to a further preferred embodiment of the present invention inside the process chamber, in particular exclusively, along the outside of the SIC growth substrate. This embodiment is beneficial since the diameter of the SIC growth substrate can be smaller compared to the case in which the gas guide path extends along the inside of the SIC growth substrate.

[0037] The heating unit inductively heats according to a further preferred embodiment of the present invention the one or at least or exactly one SIC growth substrate, wherein the heating unit is operated with alternating current with a frequency above 1kHz, in particular with a frequency above 20kHz and preferably with a frequency above 500kHz and most preferably with a frequency above 1 MHz. This embodiment is beneficial since penetration depth of an electro- Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT magnetic field can be tuned by defining or adjusting the frequency. The higher the frequency the lower the penetration depth.

[0038] The step of growing the ring-shaped SIC source material complex comprises setting up a deposition rate, in particular perpendicular deposition rate, of more than 200 pm / h, in particular of more than 250 pm / h and preferably of more than 300 pm / h and highly preferably of more than 400 pm / h and most preferably of more than 500 pm / h or of up to 2000 pm / h. The heating unit is according to a preferred embodiment of the present invention configured to inductively heat the one or at least or exactly one SIC growth substrate. This embodiment is beneficial since inductive heating is well known from other technical fields.

[0039] The heating unit comprises according to a preferred embodiment of the present invention a coil, wherein the coil is formed by a longitudinal conductor having a first end and a second end, wherein the conductor forms a plurality of turns between the first end and the second end. The turns preferably extend above at least 50% and preferably at least or up to 70% and highly preferably at least or up to 90% of the height of the SIC growth substrate.

[0040] The conductor is according to a preferred embodiment of the present invention made of tantalum. This embodiment is beneficial since the melting temperature of tantalum is very high and thus does not require any cooling of the conductor during heating.

[0041] The turns form according to a preferred embodiment of the present invention a core, wherein the core has a core center axis, and wherein the one or at least or exactly one SIC growth substrate has a SIC growth substrate center axis, wherein the coil is arranged in such a manner that the core center axis and the SIC growth substrate center axis are parallel or coaxial during operation of the SIC production reactor. This embodiment is beneficial since a very homogeneous heating of the SIC growth substrate respectively the deposition surface takes place in case the SIC growth substrate center axis and the core center axis are arranged in coaxial manner.

[0042] The conductor is according to a preferred embodiment of the present invention formed by a pipe, wherein the pipe is made of metal and wherein the pipe is configured to conduct a fluid from the first end of the conductor to the second end of the conductor for cooling the conductor. This embodiment is beneficial since the conductor can be made of less expensive materials having a melting point below 1500°C. Such metals can be e.g. copper or steal. The fluid is a gas or a liquid, in particular water or oil. A pump for circulating the fluid is preferably provided, wherein the pump is configured to circulate the fluid in such a manner to cool the conductor during operation to a maximum temperature of 1200°C and preferably to a maximum temperature of 1200°C and highly preferably to a maximum temperature of 1000°C. Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT

[0043] The heating unit is according to a preferred embodiment of the present invention configured to emit heat radiation, in particular to heat the deposition surface by means of heat radiation. This embodiment is beneficial since the costs for radiation elements are small.

[0044] The heating unit comprises according to a preferred embodiment of the present invention at least 2 and preferably at least 3 and highly preferably at least 4 heat radiation elements and most preferably up to 10 heat radiation elements arranged around the holding position. The heat radiation elements are preferably configured to be electrically heated, in particular by means of resistive heating. The heat radiation elements are preferably made of tantalum or graphite or comprise tantalum or graphite or Carbon Fiber Composite (CFG) material. Additionally or alternatively the heat radiation elements are preferably configured to be heated by means of one or multiple gas flame / s.

[0045] A glas tube, in particular made of quartz, is arranged according to a preferred embodiment of the present invention between the heating unit and the holding position for separating the reaction space from the heating unit, in particular for shielding the heating unit during operation from the source medium. This embodiment is beneficial since the glas tube is transparent for heat radiation but shields the heating unit from the source medium.

[0046] The process chamber is according to a preferred embodiment of the present invention surrounded by a bell jar, wherein an inner surface of the bell jar is polished or coated, in particular silver or gold coated. This embodiment is beneficial since heat losses can be reduced. The bell jar can be made e.g. of quartz.

[0047] The bell jar comprises according to a preferred embodiment of the present invention a cooling fluid guide unit for guiding a cooling fluid. This embodiment is beneficial since the bell jar can be made of steel.

[0048] The above-mentioned object is also solved by a ring-shaped SIC source material complex according to claim 26. The ring-shaped SIC source material complex according to the present invention consists of less than 50 pieces of SIC source material and preferably of less than 20 pieces of SIC source material and highly preferably of less than 10 pieces of SIC source material and most preferably of less than 5 pieces of SIC source material, e.g. 4 pieces of SIC source material, 3 pieces of SIC source material, 2 pieces of SIC source material or 1 piece of SIC source material, wherein a surface of a curve enveloping the ringshaped SIC source material complex defines a first size, wherein the ring-shaped SIC source material complex forms a surface having a second size, wherein the second size is less than 10 times the first size and preferably less than 5 times the first size and highly preferably less than 3 times the first size and most preferably less than 2 times the first size, wherein the ring-shaped SIC source material complex has a circular outer contour and a circular inner Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT contour, the ring-shaped SiC source material complex has a minimum mass of 1kg and preferably of 2kg and most preferably of at least or exactly 5kg, wherein at least 90% and preferably at least 95% and most preferably at least 99% of the mass of the ring-shaped SiC source material complex is 3C-SIC or 4H-SIC.

[0049] The SiC source material consists of 2 to 50 pieces of SiC source material, wherein the SiC of the SiC source material surrounds in circumferential direction a growth structure, wherein the growth structure comprises at least 80% [mass] carbon or consists of carbon or comprises at least 80% [mass] SiC or consist of SiC.

[0050] The ring-shaped SiC source material complex consists of exactly one piece, wherein the SiC source material of the ring-shaped SiC source material complex is formed on a growth structure, wherein the growth structure comprises at least 80% [mass] carbon or consists of carbon or comprises at least 80% [mass] SiC or consist of SiC, wherein the growth structure surrounds the outer contour of the ring-shaped SiC source material complex or wherein the growth structure is surrounded by the inner contour of the ring-shaped SiC source material complex.

[0051] The ring-shaped SiC source material complex consists according to a further preferred embodiment of the present invention of exactly one free-standing ring-shaped piece consisting of 3C-SiC.

[0052] Further advantages, objectives and features of the present invention are explained with reference to the following description of accompanying drawings, in which the device(s) according to the invention are shown by way of example. Components or elements of the composite wafer or method according to the invention, which at least substantially correspond in the figures with respect to their function, can be marked with the same reference signs, whereby these components or elements do not have to be numbered or explained in all figures.

[0053] Fig. 1 shows a first example of PVT reactor according to the present invention loaded with a ring-shaped SiC source material complex according to the present invention;

[0054] Fig. 2a shows a further example of a PVT reactor according to the present invention loaded with a first type of a free standing ring-shaped SiC source material complex;

[0055] Fig. 2b a top view of a ring-shaped SiC source material complex; Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT

[0056] Fig. 2c-f cross-sectional views of differently shaped ring-shaped SiC source material complexes;

[0057] Fig. 3 a further example of a PVT a PVT reactor according to the present invention loaded with a ring-shaped SiC source material complex;

[0058] Fig. 4a shows an example of a CVD production reactor for the production of PVT source material;

[0059] Fig. 4b-d different configurations of deposited SiC on a SiC growth substrate;

[0060] Fig. 4e a step of dividing, in particular cutting, a SiC growth substrate with deposited

[0061] SiC into multiple pieces;

[0062] Fig. 4f a step of forming a ring-shaped SiC source material complex;

[0063] Fig. 5a a further CVD production reactor for the production of PVT source material;

[0064] Fig. 5b / c different views of a ring-shaped SiC source material complex;

[0065] Fig. 6a a further CVD production reactor for the production of PVT source material;

[0066] Fig. 6b / c different views of a ring-shaped SiC source material complex.

[0067] Fig. 7a / b show crucible units (e.g. like shown in Fig. 1), wherein said crucible units are loaded with different types of source material but are heated in the same manner.

[0068] Fig. 1 shows a furnace apparatus 100, in particular a furnace apparatus 100 for growing crystals, and in particular for growing SiC crystals. The furnace apparatus 100 preferably comprises a furnace unit 102 which incorporates one or at least one or exactly one crucible unit 106. The furnace unit 102 is defined by a furnace housing 108 which has a furnace housing inner surface 240 and a furnace housing outer surface 242. The crucible unit 106 is defined by a crucible housing 110 which has a crucible housing outer surface 112 and a crucible housing inner surface 114. The crucible housing inner surface 114 at least partially and preferably entirely defines a crucible volume 116. The furnace housing inner surface 240 and the crucible housing outer surface 112 define a furnace volume 104. The furnace apparatus 100 also comprises a receiving space 118 for receiving a ring-shaped source material complex 120. The receiving space 118 is arranged or formed inside the crucible Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT volume 116 and / or as part of the crucible housing 110. Furthermore, a seed holder unit 122 for holding a defined seed wafer 18 is arranged inside the crucible volume 116. The furnace unit 102 also comprises one or at least one or exactly one heating unit 124 / 125 for heating the ring-shaped source material complex 120.

[0069] The receiving space 118 for receiving the ring-shaped source material complex 120 is preferably arranged on a level below the seed holder unit 122 and on a level above the bottom heating unit 124. Additionally, or alternatively a side heating unit 125 can be provided.

[0070] The crucible housing 110 preferably comprises carbon, in particular at least 50% (mass) of the crucible housing 110 is made of carbon and preferably at least 80% (mass) of the crucible housing 110 is made of carbon and more preferably at least 90% (mass) of the crucible housing 110 is made of carbon or the crucible housing 110 complete consists of carbon, in particular the crucible housing 110 comprises at least 90% (mass) graphite or consists of graphite, to withstand temperatures above 2,000°C, in particular at least or up to 3,000°C or at least up to 3,000°C or up to 3,500°C or at least up to 3,500°C or up to 4,000°C or at least up to 4,000°C, wherein the crucible housing 110 is minimally permeable to silicon gas (Si vapor).

[0071] Fig. 2a shows a further example of components of a PVT reactor according to the present invention. The receiving space 118 does not comprise specific stockades or recesses or the like shaped to entirely circumvent source material since the ring-shaped source material complex 120 is highly preferably free standing.

[0072] Reference signs D1 and D2 indicate that the seed wafer or seed solid 18 preferably overlaps in vertical direction the top surface of the ring-shaped source material complex 120, wherein D1 represents the diameter of the seed solid or seed wafer 18 and wherein D2 is between 5% and 40% of D1 and preferably between 10% and 30% and highly preferably between 15% and 25% and most preferably between 18% and 22% respectively about 20% or exactly 20%.

[0073] Reference number 127 indicates a gas guide unit, in particular a gas guide plate. The gas guide unit 127, in particular the gas guide plate, directs the sublimed source material during production to the center of the crucible respectively to the surface of the seed solid or seed wafer 18.

[0074] The ring-shaped source material complex 120 shown in fig. 2a corresponds in the present example to the one shown in fig. 2f. However, it has to be understood that a ring-shaped Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT source material complex 120 having a different shape, e.g. one of the shapes shown in Fig. 2c-e, could be alternatively used.

[0075] Thus, fig. 2c-f schematically show preferred shapes of the ring-shaped source material complex 120 as it is provided as a source material for the PVT process. The ring-shaped source material complexes 120 can be produced in one or more pieces and consist purely of SiC or alternatively of SiC and carbon.

[0076] Fig. 2b shows that the ring-shaped source material complex 120 preferably has a circular inner contour 128 and a circular outer contour 130. The ring-shaped source material complex 120 preferably consists of one piece respectively is a monolithic structure. Alternatively the ring-shaped source material complex 120 may consist of more than 1 piece, in particular of up to 50 and preferably up to 20 and highly preferably up to 10 and most preferably up to 4 or 2 pieces.

[0077] Fig. 3 shows a further example of a PVT reactor 100 according to the present invention. The PVT reactor comprises in this example a gas flow homogenization device 150. The gas flow homogenization device 150 is preferably arranged in the gas flow path between the SiC seed solid 18 and the source material receiving section 118, wherein the gas flow homogenization device 150 is highly preferably arranged closer to the SiC seed 18 than to the source material receiving section 118. The gas flow homogenization device 150 comprises at least 80% [mass] carbon or consists of carbon or comprises at least 80% [mass] SiC or consist of SiC and has a plate like shape and comprises more than 10 holes 152 and preferably more than 50 holes 152 and highly preferably more than 100 152 holes and more than 200 holes 152, wherein said holes extend in the direction of the gas flow path.

[0078] It is also possible to provide such a gas flow homogenization device 150 as part of the PVT reactors 100 shown in fig. 1 and 2.

[0079] Fig. 4a shows an example of a production device 850 for producing SiC material, in particular 3C-SiC material. This device 850 comprises a first feeding device 851 , a second feeding device 852 and a third feeding device 853. The first feed device 851 is preferably designed as a first mass flow controller, in particular for controlling the mass flow of a first source fluid, in particular a first source liquid or a first source gas, wherein the first source fluid preferably comprises Si, in particular e.g. si lanes / chlorosi lanes of the general composition SiH4-mClm or organochlorosilanes of the general composition SiR4-mClm (where R = hydrogen, hydrocarbon or chlorohydrocarbon). The second feed device 852 is preferably designed as a second mass flow controller, in particular for controlling the mass flow of a second source fluid, in particular a second source liquid or a second source gas, wherein the second source fluid preferably comprises C, e.g. hydrocarbons or chlorohydrocarbons, preferably with a Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT boiling point < 100 °C, particularly preferably methane. The third feed device 853 is preferably designed as a third mass flow controller, in particular for controlling the mass flow of a carrier fluid, in particular a carrier gas, wherein the carrier fluid or carrier gas preferably comprises H or H2, respectively, or mixtures of hydrogen and inert gases.

[0080] The reference sign 854 indicates a mixing device or a mixer by which the source fluids and / or the carrier fluid can be mixed with one another, in particular in predetermined ratios. The reference sign 855 indicates an evaporator device or an evaporator by which the fluid mixture which can be supplied from the mixing device 854 to the evaporator device 855 can be evaporated.

[0081] The evaporated fluid mixture is then fed to a process chamber 856 or a separator vessel, which is designed as a pressure vessel. At least one SIC growth substrate 857 and preferably several SIC growth substrates 857, in particular up to 20 SIC growth substrates, are arranged in the process chamber 856, wherein Si and C are deposited from the vaporized fluid mixture at the SIC growth substrate 857 and SIC is formed.

[0082] The reference sign 858 indicates a temperature measuring device, which is preferably provided for determining the surface temperature of the SIC growth substrate 857 and is preferably connected to a control device (not shown) by data and / or signal technology.

[0083] The reference sign 859 indicates an energy source, in particular for introducing electrical energy into the SIC growth substrate 857 for heating the separating element. A first electrode 859a is preferably coupled to a first end of the SIC growth substrate 857 and a second electrode 859b is preferably coupled to a second end of the SIC growth substrate 857 for resistively heating the SIC growth substrate 857. The energy source 859 is thereby preferably also connected to the control device in terms of signals and / or data. Preferably, the control device controls the energy supply, in particular power supply, through the SIC growth substrate 857 depending on the measurement signals and / or measurement data output by the temperature measurement device 858.

[0084] Furthermore, a pressure holding device is indicated by the reference sign 860. The pressure holding device 860 can preferably be implemented by a pressure-regulated valve or the working pressure of a downstream exhaust gas treatment system.

[0085] A control unit is for setting up a feed medium supply of the one feed-medium or the multiple feed-mediums into the reaction space 966 is indicated by reference number 926, wherein the control unit 926 is configured to set up the feed medium supply between a minimum amount of feed medium supply [mass] per min. and a maximum amount of feed medium supply [mass] per min., wherein the minimum amount of feed medium supply [mass] per min. Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT corresponds to a deposited minimum amount of Si [mass] and a minimum amount of C [mass] at the defined growth rate.

[0086] The SiC growth substrate 857 is preferably ring shaped respectively at least mainly ring shaped respectively comprises a ring-shaped section, wherein the ring shaped section of the SiC growth substrate 857 extends in a circular direction. The SiC growth substrate 857 is coupled to a first electrode 859a and a second electrode 859b for resistively heating the SiC growth substrate 857. The SiC growth substrate 857 preferably consists of SiC or Carbon.

[0087] Fig. 4b shows an example of the ring-shaped section of the SiC growth substrate 857 after deposition of SiC in a CVD reactor.

[0088] Fig. 4c shows a perspective view of Fig. 4a and that the ring-shaped section of the SiC growth substrate 857 preferably extends in one plane respectively is preferably entirely parallel to a plane (e.g. virtual plane P).

[0089] Fig. 4d schematically shows a cross-sectional view indicated by A-A’ (cf. Fig. 4c). SiC growth substrate 857 is surrounded by SiC 880 deposited in a CVD reactor 850 onto the SiC growth substrate 857.

[0090] Fig 4e schematically shows the SiC growth substrate 857 with the deposited SiC (as shown in fig. 4c) but without the connections (857a / 857b) to the electrodes 859a, 859b.

[0091] Fig. 4e also shows that the SiC growth substrate 857 with the deposited SiC can be divided in multiple parts, in particular in less than 100 parts and preferably less than 50 parts and highly preferably in less than 20 parts.

[0092] A SiC growth substrate 857 with the deposited SiC forming an “open ring” (cf. fig. 4f left side) can be modified by adding a piece 142 divided from another SiC growth substrate 857 with deposited SiC (as shown in fig. 4e) to assemble an example of a ring-shaped source material complex 120 according to the present invention. Said ring-shaped source material complex 120 can be placed into a receiving space of a PVT reactor 100 as source material.

[0093] Fig. 5a shows components of a SiC production reactor 850 according to the present invention. The SiC production reactor 850 comprises a heating unit 954, wherein the heating unit 954 preferably comprises a conductor 2830 forming a coil 2828. The conductor 2830 comprises a first end 2832 and a second end 2834, wherein the first end 2832 and the second end 2834 are preferably arranged or positioned in a coupling unit 2858. The first end 2832 and the second end 2834 are preferably fixed by welding (cf. reference number 2860) to the coupling unit 2858. Reference number 866 indicates a gas flow into a reaction space Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT

[0094] 966 and reference number 216 indicates a gas flow out of the reaction space 966, in particular into a vent gas recycling unit (not shown).

[0095] A first end 2854 of the SiC growth substrate 857 is preferably arranged or positioned in a holding section 2824a, wherein the holding section 2824a can be configured as electrode 859a or electric isolator, in particular made of graphite. A second end 2856 of the SiC growth substrate 850 is preferably arranged or positioned in a holding section 2824b, wherein the holding section 2824b can be configured as electrode 859b or electric isolator, in particular made of graphite.

[0096] The SiC growth substrate 857 has a center axis and a cylindrical shape and preferably a cylindrical through hole.

[0097] In case a through hole is present the cylindrical through hole has a through hole center axis, wherein the through hole center axis and the center axis are coaxial, wherein the cylindrical through hole has a through hole diameter and wherein the cylindrical shape has a cylindrical shape outer diameter, wherein the through hole diameter is between 50% and 95% of the cylindrical shape outer diameter, Deposition of SiC takes place on the outer surface 2826 of the SiC growth substrate 857.

[0098] The SiC production reactor 850 preferably comprises a glas tube 2848, in particular made of quartz, which is arranged between the heating unit 954 and the holding position for separating the process chamber from the heating unit 954, in particular for shielding the heating unit 954 during operation from the source medium.

[0099] A gas guide path along which the source fluid travels extends along the outside of the SiC growth substrate 857 and the inside of the glas tube 2848.

[0100] Fig. 5b shows schematically a top view of a ring-shaped SiC source material complex 120 according to the present invention and produced with a CVD reactor as shown e.g. in fig. 5a. Said ring-shaped SiC source material complex 120 consists of 1 piece of SiC source material.

[0101] The ring-shaped SiC source material complex 120 has a circular outer contour and a circular inner contour.

[0102] The ring-shaped SiC source material complex 120 has a minimum mass of 1 kg and preferably of 2kg or at least 2kg and highly preferably of 5kg or of more than 5kgand preferably of up to 20kg, wherein at least 90% and preferably at least 95% and most preferably at least 99% of the mass of the ring-shaped SiC source material complex 120 is 3C-SiC or 4H-SiC. Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT

[0103] The SiC source material of the ring-shaped SIC source material complex 120 is formed on a growth structure 857. The growth structure 857 form or is at least one section of a SiC growth substrate 857 which is heated during SiC production inside the CVD reactor to allow SiC deposition. The growth structure 857 comprises at least 80% [mass] carbon or consists of carbon or comprises at least 80% [mass] SiC or consist of SiC.

[0104] Fig. 5c shows a cross sectional view. Furthermore, fig. 5c shows that the growth structure 857 is surrounded by the inner contour of the deposited SiC of the ring-shaped SiC source material complex 120.

[0105] Fig. 6a shows components of another SiC production reactor 850 similar to the one shown in Fig. 5a. The SiC generator comprises a generator 2844 coupled with the conductor 2830. The generator is preferably configured to provided alternating current with at least one frequency above 10kHz, in particular above 500kHz and highly preferably above 1 MHz and most preferably up to 1GHz. Reference number 2836 indicates a plurality of turns. The coil 2828 comprises preferably at least four turns or more than or up to 8 turns or highly preferably more than or up to 20 turns and most preferably more than or up to 100 turns. The SiC growth substrate 857 has a center axis and a cylindrical shape and a cylindrical through hole, wherein the cylindrical through hole has a through hole center axis, wherein the through hole center axis and the center axis are coaxial, wherein the cylindrical through hole has a through hole diameter and wherein the cylindrical shape has a cylindrical shape outer diameter, wherein the through hole diameter is between 50% and 95% of the cylindrical shape outer diameter, Deposition of SiC takes place on the surface of through hole. The source medium preferably travels through the through hole during SiC deposition.

[0106] Fig. 6b shows schematically a top view of a ring-shaped SiC source material complex 120 according to the present invention and produced with a CVD reactor as shown e.g. in fig. 5a. Said ring-shaped SiC source material complex 120 consists of 1 piece of SiC source material.

[0107] The ring-shaped SiC source material complex 120 has a circular outer contour and a circular inner contour.

[0108] The ring-shaped SiC source material complex 120 has a minimum mass of 1 kg and preferably of 2kg or at least 2kg and highly preferably of 5kg or of more than 5kg and most preferably of up to 20 kg, wherein at least 90% and preferably at least 95% and most preferably at least 99% of the mass of the ring-shaped SiC source material complex 120 is 3C-SiC or 4H-SiC. Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT

[0109] The SiC source material of the ring-shaped SIC source material complex 120 is formed on a growth structure 857. The growth structure 857 form or is at least one section of a SiC growth substrate 857 which is heated during SiC production inside the CVD reactor to allow SiC deposition. The growth structure 857 comprises at least 80% [mass] carbon or consists of carbon or comprises at least 80% [mass] SiC or consist of SiC.

[0110] Fig. 6c shows a cross sectional view. Furthermore, fig. 6c shows that the growth structure surrounds the outer contour of the ring-shaped SiC source material complex 120.

[0111] Thus, fig. 5a and 6a show examples of a CVD SiC production reactor 850, said CVD SiC production reactor preferably comprises one or at least a process chamber 856, a gas inlet unit 866 for feeding one feed-medium or multiple feed-mediums into the process chamber 856 for providing a source medium, wherein the gas inlet unit 866 is coupled with at least one feed-medium source 851 , or wherein the gas inlet unit 866 is coupled with at least two feed-medium sources 851 , 852, or wherein the gas inlet unit 866 is coupled with at least or exactly or up to three feed-medium sources 851 , 852, 853, a gas outlet unit 216 for removing a vent gas mixture from the reaction space of the process chamber 856, a holding section 2824 for holding one or at least or exactly one SiC growth substrate 857 inside the process chamber in a holding position, a heating unit 954 for heating a deposition surface 861 of the one or at least or exactly one SiC growth substrate, wherein the heating unit 954 is configured to heat the one or at least or exactly one SiC growth substrate 857 from at least multiple sides, in particularly along the entire circumference 2826 of the at least or exactly one SiC growth substrate 857.

[0112] The heating unit 954 is preferably configured to inductively heat the one or at least or exactly one SiC growth substrate 857. The heating unit 954 can be configured to provide alternating current with a frequency above 1 kHz, in particular with a frequency above 20kHz and preferably with a frequency above 50kHz and most preferably with a frequency above 100kHz. The heating unit 954 preferably comprises a coil 2828 wherein the coil 2828 can be formed by a longitudinal conductor 2830 having a first end 2832 and a second end 2834, wherein the conductor 2830 forms a plurality of turns 2836 between the first end 2832 and the second end 2834. The conductor 2830 is highly preferably made of tantalum. The turns 2836 preferably form a core, wherein the core has a core center axis 2838, and wherein the one or at least or exactly one SiC growth substrate 857 has a SiC growth substrate center axis 2840, wherein the coil 2828 is arranged in such a manner that the core center axis 2838 and the SiC growth substrate center axis 2840 are parallel or coaxial during operation of the SiC production reactor 850. The conductor 2830 can be formed by a pipe, wherein the pipe is made of metal and wherein the pipe is configured to conduct a fluid from the first end 2832 Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT of the conductor 2830 to the second end 2834 of the conductor 2830 for cooling the conductor 2830.

[0113] Alternatively, the heating unit 954 can be configured to emit heat radiation, in said configuration the heating unit 954 preferably comprises at least 2 and preferably at least 3 and highly preferably at least 4 and most preferably up to 10 heat radiation elements arrange around the holding position.

[0114] Fig. 7a and 7b show crucible units 106 (e.g. like shown in Fig. 1), wherein said crucible units are loaded with different types of source material but are heated in the same manner.

[0115] The crucible unit 106 of Fig. 7a is loaded with source material powder (average particle size preferably between 3-12mm respectively the longest extension in one direction of an average particle is between 3-12mm) of 3C-SIC.

[0116] The crucible unit 106 of Fig. 7a is loaded with one source material piece of 3C SIC or with a few source material pieces of 3C SIC, wherein the term a “few source material pieces” describes less than 100 pieces and preferably less than 10 pieces and highly preferably less than 5 pieces.

[0117] Neither the source material powder 119 not the ring-shaped source material complex 120 was not hatched to improve the visibility of the isotherms. Only the graphite casing 121 of the powder was hatched (Fig. 7a). Thus, the source material 119 / 120 preferably only varies with respect to the average piece size.

[0118] The isotherms - resulting from simulations - show significant differences depending on the used source material.

[0119] Isotherm 1 (cf. reference number 2860) of powder source material 119 indicates the same temperature as Isotherm 1 (cf. reference number 2864) of solid source material 120.

[0120] Isotherm 2 (cf. reference number 2862) of powder source material 119 indicates the same temperature as Isotherm 2 (cf. reference number 2866) of solid source material 120.

[0121] The powder / chunks surface change during powder evaporation and redistribution of the source material in the source compartment will change both the evaporation surface and the thermal profile.

[0122] Having e.g. on the on hand side source material particles 119 (average particle size 3-12 mm respectively the longest extension in one direction of an average particle is between 3- 12mm) arranged in a ring shaped manner, wherein the ring shape has the following dimensions: Inner diameter of 125mm, outer diameter of 125mm and a height of 200mm. A surface size between 58347 sqcm and 67892 sqcm results in said setting. Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT

[0123] Having e.g. on the other hand side a solid ring-shaped source material complex 120 having the following dimensions: Inner diameter of 125mm, outer diameter of 125mm and a height of 200mm. A surface size of 2749 sqcm results. Thus, the surface of the powder is about 21 - 25 times larger.

[0124] Thus, the sublimation surface varies in the case of a solid source from begin of consumption to the end of consumption (fully consumed) by factor 4.375, that means that the resulting rest structure has a surface size of about 23% of the surface size at start of the sublimation. The rest structure mainly (mass %) consists of carbon.

[0125] The sublimation surface varies in the case of a powder source (3-12 mm powder source material) from begin of consumption to the end of consumption (fully consumed) by factor 93 to 98, that means that the resulting rest structure has a surface size of about 1 ,03% to 1 ,07% of the surface size at start of the sublimation. The rest structure mainly (mass %) consists of carbon.

[0126] The simulation shows that the temperature drift inside the source is significant for powder and temperature is exponential on evaporation rate while the surface is only square. So, both factors are playing role but mostly the temperature hot-spot drift inside the source. This drift is less in denser source. The simulation shows that temperature distribution uniformity is 78% more uniform for the solid source.

[0127] Large solid piece / es eliminate the need to cage the source in porous graphite 121 providing a manufacturing advantage (simplicity and cost reduction).

[0128] Large solid piece / es respectively a solid ring source has more stable thermal properties like thermal conductivity and thermal capacity in comparison with the powder and chunk based.

[0129] This leads to more stable temperature distribution in the growth zone. The latter ensures more stable evaporation rate of the source material during the growth and more stable thermal conditions of the crystal growth front that leads to reduced stress and lower defect formation during the growth. Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT

[0130] List of reference numbers

[0131] 18 seed wafer / seed solid 150 homogenization device, in particular homogenization plate

[0132] 20 grown crystal

[0133] 152 through holes of the

[0134] 100 furnace apparatus / PVT reactor homogenization device

[0135] 102 furnace unit

[0136] 240 furnace housing inner surface

[0137] 106 crucible unit

[0138] 242 furnace housing outer surface

[0139] 108 furnace housing

[0140] 850 manufacturing device or CVD unit

[0141] 110 crucible housing or CVD reactor respectively SiC

[0142] 112 crucible housing outer surface production reactor, in particular SiC PVT source material production reactor

[0143] 114 crucible housing inner surface

[0144] 851 first feeding device respectively first

[0145] 116 crucible volume feed-medium source

[0146] 118 receiving space / source material

[0147] 852 second feeding device respectively receiving section second feed-medium source

[0148] 119 source material powder

[0149] 853 third feeding device respectively

[0150] 120 ring-shaped source material third feed-medium source respectively complex carrier gas feed-medium source

[0151] 122 seed holder unit or seed holding 854 mixing device device 855 evaporator device

[0152] 124 bottom heating unit

[0153] 856 process chamber

[0154] 125 side heating unit

[0155] 857 separating element or SiC growth

[0156] 127 gas guide plate substrate or deposition substrate

[0157] 128 circular inner contour 857a first end of SiC growth substrate

[0158] 129 inner diameter 857b second end of SiC growth substrate

[0159] 130 circular outer contour

[0160] 858 temperature measuring device or

[0161] 131 outer diameter temperature control unit

[0162] 140 open ring

[0163] 859 Energy source, especially power

[0164] 142 further piece supply Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT

[0165] 859a first power connection 2832 first end conductor

[0166] 859b second power connection 2834 second end conductor

[0167] 860 Pressure maintaining device or 2836 plurality of turns pressure control unit

[0168] 2848 glas tube

[0169] 861 outer surface of SiC growth

[0170] 2854 first end of the SiC growth substrate or SiC growth surface substrate

[0171] 862 base plate

[0172] 2856 second end of the SiC growth

[0173] 864 bell jar substrate

[0174] 864a side wall section 2858 coupling unit

[0175] 864b top wall section 2860 Isotherm 1 of powder source material

[0176] 865 metal surface

[0177] 2862 Isotherm 2 of powder source

[0178] 866 gas inlet unit material

[0179] 880 SiC deposited in a CVD process

[0180] 2864 Isotherm 1 of solid source material

[0181] 926 control device or control unit

[0182] 2866 Isotherm 2 of solid source material

[0183] 954 heating unit

[0184] 966 reaction space

[0185] 2824a holding section

[0186] A1 central axis of the ring-shaped SiC

[0187] 2824b holding section source material complex

[0188] 2826 outer surface of the SiC growth A2 central axis of the SiC seed solid substrate

[0189] D1 diameter of the SiC seed solid

[0190] 2827 inner surface of the SiC growth

[0191] D2 overlap substrate

[0192] S section

[0193] 2828 coil

[0194] P plane

[0195] 2830 conductor

Claims

Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCTClaims1. Method for the production of at least or exactly one monocrystalline SiC solid (20), in particular wafer,At least comprising the steps:Providing a PVT reactor (100), wherein the PVT reactor (100) comprises a source material receiving section (118) and a SiC seed solid, in particular SiC seed wafer, holding device (122),Coupling a SiC seed solid (18) to the SiC seed solid holding device (122), wherein the SiC seed solid (18) has a diameter of at least 10 cm,Positioning of a ring-shaped SiC source material complex (120) in the source material receiving section (118), wherein the ring-shaped SiC source material complex (120) is formed by one or multiple pieces (140, 142) of SiC source material,Generating gaseous SiC by subliming the SiC source material complex (120),Growing monocrystalline SiC (20) by depositing the gaseous SiC onto the SiC seed solid (18).

2. Method according to claim 1 , characterized in that the ring-shaped SiC source material complex (120) has an inner diameter (129), wherein the inner diameter (129) is between 5 / 10 and 10 / 10 of the diameter (D1) of the SiC seed solid (18) and preferably between 6 / 10 and 9,5 / 10 of the diameter (D1 ) of the SiC seed solid (18) and most preferably between 6 / 10 and 8 / 10 of the diameter (D1) of the SiC seed solid (18), and wherein the ring-shaped SiC source material complex (120) has an outer diameter (131), wherein the outer diameter (131 ) is equal to or larger than 10 / 10 of the diameter (D1 ) of theKehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCTSiC seed solid (18) and preferably larger than 11 / 10 of the diameter (D1) of the SiC seed solid (18) and particular preferably larger than 12 / 10 of the diameter (D1) of the SiC seed solid (18) and most preferably between 11 / 10 and 25 / 10 of the diameter (D1) of the SiC seed solid (18), in particular between 12 / 10 and 20 / 10 of the diameter (D1) of the SiC seed solid (18) or between 12 / 10 and 15 / 10 of the diameter (D1 ) of the SiC seed solid (18).

3. Method according to claim 1 or 2, characterized in that the average density of the SiC of the ring-shaped SiC source material complex (120) is larger than 3g / cm3and preferably larger than 3,1g / cm3and most preferably larger than 3,2g / cm3.

4. Method according to at least one of the preceding claims, characterized in that the ring-shaped SiC source material complex (120) consists of less than 50 pieces (140, 142) of SiC source material and preferably of less than 20 pieces of SiC source material and highly preferably of less than 10 pieces of SiC source material and most preferably of less than 5 pieces of SiC source material, e.g. 4 pieces of SiC source material, 3 pieces of SiC source material, 2 pieces of SiC source material or 1 piece of SiC source material.

5. Method according to at least one of the preceding claims, characterized in that a surface of a curve enveloping the ring-shaped SiC source material complex (120) defines a first size, wherein the ring-shaped SiC source material complex (120) forms a surface having a second size, wherein the second size is less than 10 times the first size and preferably less than 5 times the first size and highly preferably less than 3 times the first size and most preferably less than 2 times the first size.

6. Method according to at least one of the preceding claims, characterized in thatKehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT the ring-shaped SiC source material complex (120) has a circular outer contour (130) and a circular inner contour (128).

7. Method according to at least one of the preceding claims, characterized in that the ring-shaped SiC source material complex (120) is positioned inside the source material receiving section (118) in such a manner that a central axis (A1) of the ring-shaped SiC source material complex (120) is coaxial to a central axis (A2) of the SiC seed solid (18) or the ring-shaped SiC source material complex (120) is positioned inside the source material receiving section (118) in such a manner that a central axis (A1) of the ring-shaped SiC source material complex (120) is parallel to a central axis (A2) of the SiC seed solid (18), wherein the central axis (A1) of the ring-shaped SiC source material complex (120) and the central axis (A2) of the SiC seed solid (18) are in a distance to each other of less than 1 cm and preferably of less than 0,7cm and most preferably of less than 0,5cm.

8. Method according to at least one of the preceding claims, characterized in that the ring-shaped SiC source material complex (120) has a minimum mass of 1 kg, wherein at least 90% and preferably at least 95% and most preferably at least 99% of the mass of the ring-shaped SiC source material complex (120) is 3C-SiC or 4H-SiC.

9. Method according to any of claims 6 to 8, characterized in that the SiC source material of the ring-shaped SiC source material complex (120) is formed on a growth structure (857) , wherein the growth structure (857) comprises at least 80% [mass] carbon or consists of carbon or comprises at least 80% [mass] SiC or consist of SiC, wherein the growth structure (857) surrounds the outer contour (130) of the deposited SiC of the ringshaped SiC source material complex (120) or wherein the growth structure is surrounded by the inner contour (128) of the deposited SiC of the ring-shaped SiC source material complex (120).Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT10. Method according to any of claims 6 to 8, characterized in that the SIC source material of the ring-shaped SIC source material complex (120) surrounds in circumferential direction a growth structure (857), wherein the growth structure (857) comprises at least 80% [mass] carbon or consists of carbon or comprises at least 80% [mass] SIC or consist of SIC.11 . Method according to at least one of the preceding claims, characterized in that the monocrystalline SIC solid (20) of the 4H type growth to a volume of more than 400 cm3and preferably to more than or exactly 630 cm3and most preferably to more than or exactly 800 cm3and forms during growth an average dislocation density per cm2of less than 5000 dislocations per cm2and preferably an average dislocation density per cm2of less than 2000 dislocations per cm2and most preferably an average dislocation density per cm2of less than 1000 dislocations per cm2.

12. Method according to at least one of the preceding claims, characterized in that a gas flow homogenization device (150) is arranged in the gas flow path between the SIC seed solid holding device (122) and the source material receiving section (118), wherein the gas flow homogenization device (150) is arranged closer to the SIC seed solid holding device (122) than to the source material receiving section (118).

13. Method according to claim 12, characterized in that the gas flow homogenization device (150) comprises at least 80% [mass] carbon or consists of carbon or comprises at least 80% [mass] SIC or consist of SIC and has a plate like shape and comprises more than 10 holes (152) and preferably more than 50 holes (152) and highly preferably more than 100 holes (152) and more than 200 holes (152), wherein said holes extend in the direction of the gas flow path.Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT14. Method according to at least one of the preceding claims, characterized in that the PVT reactor (100) is configured for SIC growth in c-axis direction.

15. Method according to at least one of the preceding claims, characterized in that the PVT reactor (100) is configured for SIC growth in a-plane direction.

16. Monocrystalline SIC solid (20) of the 4H type, preferably produced according to any of the claims 1 to 15, having a diameter of at least 8 cm and preferably of at least 12 cm and most preferably of at least 15 cm and a thickness of at least 0,5 cm and preferably of at least 1 cm and most preferably of at least 2 cm, wherein the monocrystalline SIC solid having an average dislocation density per cm2of less than 5000 dislocations per cm2and preferably an average dislocation density per cm2of less than 2000 dislocations per cm2and most preferably an average dislocation density per cm2of less than 1000 dislocations per cm2.

17. Method for the production of a ring-shaped SIC source material complex (120), in particular for use in the method for the production of at least or exactly one monocrystalline SIC solid (20) according to the claims 1 to 15, at least comprising the steps providing a CVD reactor (850), arranging at least one SIC growth substrate (857) inside the CVD reactor (850), wherein the step of arranging at least one SIC growth substrate (857) inside the CVD reactor (850) comprises the steps of connecting at least a first end (857a) of a SIC growth substrate (857) to a first electrode (859a) and connecting a second end (857b) of the SIC growth substrate (857) to a second electrode (859b), heating the SIC growth substrate (857) by conducting current from the first electrode (859a) to the second electrode (859b) or vice versa,Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT feeding a source gas into the CVD reactor (850) for depositing 3C SiC onto the heated SiC growth substrate (857), characterized in that at least one section (S) of the SiC growth substrate (857) formed between the first end (857a) and the second end (857b) extends in a circular direction, wherein the at least one section (S) of the SiC growth substrate (857) extends at least 90° in a circular direction and preferably at least or up to or exactly 180° and particular preferably at least or up to or exactly 270° and most preferably up to or exactly 340°.

18. Method for the production of a ring-shaped SiC source material complex (120) according to claim 17, characterized in that the at least one section (S) of the SiC growth substrate (857) extends parallel to one plane (P)-19. Method for the production of a ring-shaped SiC source material complex (120), in particular for use in the method for the production of at least or exactly one monocrystalline SiC solid (20) according to the claims 1 to 15, at least comprising the steps providing at least one piece of 4H SiC, dividing the at least one piece of 4H SiC in sub-pieces, in particular of the same size, wherein each sub-piece of the majority [mass %] of sub-pieces extends in at least one direction more than 2cm and preferably more than 5cm and most preferably up to 10cm or up to 15cm, forming the ring-shaped SiC source material complex (120) by arranging said sub-pieces in a circular manner.

20. CVD SiC production reactor (850), at least comprising a process chamber (856),Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT a gas inlet unit (866) for feeding one feed-medium or multiple feed-mediums into the process chamber (856) for providing a source medium, wherein the gas inlet unit (866) is coupled with at least one feed-medium source (851), or wherein the gas inlet unit (866) is coupled with at least two feed-medium sources (851 , 852), or wherein the gas inlet unit (866) is coupled with at least three feed-medium sources (851 , 852, 853), a gas outlet unit (216) for removing a vent gas mixture from the reaction space of the process chamber (856), a holding section (2824) for holding at least or exactly one SiC growth substrate (857) inside the process chamber in a holding position, wherein the SiC growth substrate (857) has a center axis and a cylindrical shape and a cylindrical through hole, wherein the cylindrical through hole has a through hole center axis, wherein the through hole center axis and the center axis are coaxial, wherein the cylindrical through hole has a through hole diameter and wherein the cylindrical shape has a cylindrical shape outer diameter, wherein the through hole diameter is between 50% and 95% of the cylindrical shape outer diameter, a heating unit (954) for heating at least a deposition surface (861) of the at least or exactly one SiC growth substrate, wherein the heating unit (954) is configured to heat the at least or exactly one SiC growth substrate (857) from at least multiple sides, in particularly along the entire circumference (2826) of the at least or exactly one SiC growth substrate (857).21 . Method for producing a ring-shaped SiC source material complex (120), at least comprising the steps: providing a CVD SiC production reactor (850), in particular according claim 20, holding the at least or exactly one SiC growth substrate (857) inside the process chamber in a holding position by means of a holding section (2854), wherein the SiC growth substrate (857) has a center axis and a cylindrical shape and a cylindrical through hole, wherein the cylindrical through hole has a through hole center axis,Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT wherein the through hole center axis and the center axis are coaxial, wherein the cylindrical through hole has a through hole diameter and wherein the cylindrical shape has a cylindrical shape outer diameter, wherein the through hole diameter is between 50% and 95% of the cylindrical shape outer diameter, heating the deposition surface of the at least or exactly one SIC growth substrate (857) by means of a heating unit transfer SIC from the source medium on a deposition surface of the at least or exactly one SIC growth substrate, wherein the heating unit is configured to heat the at least or exactly one SIC growth substrate (857) from at least multiple sides, in particularly along an entire circumference of the at least or exactly one SIC growth substrate (857), in particular by means of heat radiation or inductive heating or resistive heating, feeding one feed-medium or multiple feed-mediums into the process chamber (856) for providing a source medium, growing a ring-shaped SIC source material complex (211), removing a vent gas mixture from the process chamber (856).

22. Method according to claim 21 , characterized in that the heating unit inductively heats the at least or exactly one SIC growth substrate (857), wherein the heating unit is operated with alternating current with a frequency above 1 kHz, in particular with a frequency above 20kHz and preferably with a frequency above 500kHz and most preferably with a frequency above 1 MHz and / or wherein the step of growing the ring-shaped SIC source material complex (211) comprises setting up a deposition rate, in particular perpendicular deposition rate, of more than 200 pm / h, in particular of more than 250 pm / h and preferably of more than 300 pm / h and highly preferably of more than 400 pm / h and most preferably of more than 500 pm / h or of up to 2000 pm / h.

23. Ring-shaped SIC source material complex, characterized in that the ring-shaped SIC source material complex (120) consists of less than 50 pieces of SIC source material and preferably of less than 20 pieces of SIC source material and highlyKehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT preferably of less than 10 pieces of SIC source material and most preferably of less than 5 pieces of SIC source material, e.g. 4 pieces of SIC source material, 3 pieces of SIC source material, 2 pieces of SiC source material or 1 piece of SiC source material, wherein a surface of a curve enveloping the ring-shaped SiC source material complex (120) defines a first size, wherein the ring-shaped SiC source material complex forms a surface having a second size, wherein the second size is less than 10 times the first size and preferably less than 5 times the first size and highly preferably less than 3 times the first size and most preferably less than 2 times the first size, wherein the ring-shaped SiC source material complex (120) has a circular outer contour (130) and a circular inner contour (128), wherein the ring-shaped SiC source material complex (120) has a minimum mass of 1 kg and consists of 3C-SiC or 4H-SiC.

24. Ring-shaped SiC source material complex according to claim 23 characterized in that the SiC source material consists of 2 to 50 pieces of SiC source material, wherein the SiC of the SiC source material surrounds in circumferential direction a growth structure (857), wherein the growth structure (857) comprises at least 80% [mass] carbon or consists of carbon or comprises at least 80% [mass] SiC or consist of SiC.

25. Ring-shaped SiC source material complex according to claim 23 characterized in that the ring-shaped SiC source material complex (120) consists of exactly one piece, wherein the SiC source material of the ring-shaped SiC source material complex (120) is formed on a growth structure (857), wherein the growth structure (857) comprises at least 80% [mass] carbon or consists of carbon or comprises at least 80% [mass] SiC or consist of SiC, wherein the growth structure (857) surrounds the outer contour of the ring-shaped SiC source material complex (120) or wherein the growth structure(857) is surrounded by the inner contour of the ring-shaped SiC source material complex (120).

26. Ring-shaped SiC source material complex according to claim 23Kehl, Ascherl, Liebhoff & Ettmayr 31.10.2024 Patentanwalte * Partnerschaft mbB 5160-45-PCT characterized in that the ring-shaped SiC source material complex (120) consists of exactly one free standing ring-shaped piece, wherein at least 90% and preferably at least 95% and most preferably at least 99% of the mass of the ring-shaped SiC source material complex (120) is 3C-SiC.

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