Method and Device for Producing a SiC Solid Material

Abstract

The present invention relates to a method for producing a preferably elongated SiC solid, in particular of polytype 3C. The method according to the invention preferably includes at least the following steps: introducing at least a first source gas into a process chamber, said first source gas including Si, introducing at least one second source gas into the process chamber, the second source gas including C, electrically energizing at least one separator element disposed in the process chamber to heat the separator element, setting a deposition rate of more than 200 μm/h, wherein a pressure in the process chamber of more than 1 bar is generated by the introduction of the first source gas and/or the second source gas, and wherein the surface of the deposition element is heated to a temperature in the range between 1300° C. and 1800° C.

1 - 43 . (canceled) 
     
     
         44 . Method for the production of at least one SiC crystal,
 comprising the steps   providing a CVD reactor ( 850 ) for the production of SiC of a first type,
 introducing at least one source gas, in particular a first source gas, in particular SiCl3(CH3), into a process chamber ( 856 ) for generating a source medium, 
 wherein the source medium comprises Si and C, 
 introducing at least one carrier gas into the process chamber ( 856 ), the carrier gas preferably comprising H, 
 electrically energizing at least one SiC growth substrate ( 857 ) disposed in the process chamber ( 856 ) to heat the SiC growth substrate ( 857 ), 
 wherein the surface of the SiC growth substrate ( 857 ) is heated to a temperature in the range between 1300° C. and 1800° C., 
 depositing SiC of the first type onto the SiC growth substrate ( 857 ), in particular at a deposition rate of more than 200 μm/h, wherein the deposited SiC is preferably polycrystalline SiC, 
   removing the deposited SiC of the first type from the CVD reactor ( 850 ),   transforming the removed SiC into fragmented SiC of the first type or into one or multiple solid bodies SiC of the first type,   providing a PVT reactor ( 100 ) for the production of SiC of a second type,
 wherein the PVT reactor ( 100 ) comprises 
 a furnace unit ( 102 ), 
 wherein the furnace unit ( 102 ) comprises a furnace housing ( 108 ) with an outer surface ( 242 ) and an inner surface ( 240 ), 
 at least one crucible unit ( 106 ) 
 wherein the crucible unit ( 106 ) is arranged inside the furnace housing ( 108 ), 
 wherein the crucible unit ( 106 ) comprises a crucible housing ( 110 ), 
 wherein the crucible housing ( 110 ) has an outer surface ( 112 ) and an inner surface ( 114 ), wherein the inner surface ( 114 ) at least partially defines a crucible volume ( 116 ), 
 wherein a receiving space ( 118 ) for receiving a source material ( 120 ) is arranged or formed inside the crucible volume ( 116 ), 
 wherein a seed holder unit ( 122 ) for holding a defined seed wafer ( 18 ) is arranged inside the crucible volume ( 116 ), wherein the seed wafer holder ( 122 ) holds a seed wafer ( 18 ), 
 wherein the furnace housing inner wall ( 240 ) and the crucible housing outer wall ( 112 ) define a furnace volume ( 104 ), 
 at least one heating unit ( 124 ) for heating the source material ( 120 ), 
 wherein the receiving space ( 118 ) for receiving the source material ( 120 ) is at least in parts arranged above the heating unit ( 124 ) and below the seed holder unit ( 122 ), 
   adding the fragmented SiC of the first type or adding one or multiple solid bodies of SiC of the first type as source material ( 120 ) into the receiving space ( 118 ),   sublimating the SiC of the first type inside the PVT reactor ( 100 ) and depositing the sublimated SiC on the seed wafer ( 18 ) as SiC of the second type.   
     
     
         45 . Method according to  claim 44 ,
 characterized in that   the step of introducing at least one source gas and at least one carrier gas comprises:
 introducing at least a first feed-medium, in particular a first source gas, into the process chamber ( 856 ), said first feed medium comprises Si, in particular the Si feed medium source provides a Si gas according to the general formula SiH 4-y X y  (X═[Cl, F, Br, J] and y=[0 . . . 4], wherein the first-feed medium has a purity which excludes at least 99.9999% (ppm wt) of the substances B, Al, P, Ti, V, Fe, Ni, and 
 introducing at least a second feed-medium, in particular a second source gas, into the process chamber ( 856 ), the second feed medium comprises C, in particular natural gas, Methane, Ethan, Propane, Butane and/or Acetylene, 
 wherein the second-feed medium has a purity which excludes at least 99.9999% (ppm wt) of the substances B, Al, P, Ti, V, Fe, Ni, and 
 introducing a carrier gas, wherein the carrier gas has a purity which excludes at least 99.9999% (ppm wt) of the substances B, Al, P, Ti, V, Fe, Ni, 
   or
 introducing one feed-medium in particular a source gas, into the process chamber ( 856 ), said feed medium comprises Si and C, in particular SiCl3(CH3), wherein the feed medium has a purity which excludes at least 99.9999% (ppm wt) of the substances B, Al, P, Ti, V, Fe, Ni, and 
 introducing a carrier gas, wherein the carrier gas has a purity which excludes at least 99.9999% (ppm wt) of the substances B, Al, P, Ti, V, Fe, Ni. 
   
     
     
         46 . Method according to  claim 45 ,
 characterized in that   the fragmented SiC represents SiC particles ( 920 ), wherein the SiC particles ( 920 ) have an average length of at least 100 μm.   
     
     
         47 . Method according to  claim 46 ,
 characterized in that   wherein the SiC particles have impurities of less than 10 ppm (weight) of the substance N and of less 1000 ppb (weight), in particular of less than 500 ppb (weight), of the sum of all of the metals Ti, V, Fe, Ni.   
     
     
         48 . Method according to  claim 47 ,
 characterized in that   the tapped density of the SiC particles ( 920 ) is above 1.8 g/cm3.   
     
     
         49 . Method according to  claim 45 ,
 characterized in that   each of the one or multiple solid bodies of SiC is   characterized by   a mass of more than 0.3 kg, preferably at least 1 kg   a thickness of at least 1 cm, preferably at least 5 cm   a length of more than 10 cm, preferably at least 25 cm or at least 50 cm,   and impurities of less than 10 ppm (weight) of the substance N and of less than 1000 ppb (weight), in particular of less than 500 ppb (weight), of each of the substances B, Al, P, Ti, V, Fe, Ni.   
     
     
         50 . Method according to  claim 49 ,
 characterized in that   each of the one or multiple solid bodies of SiC has impurities of less than 10 ppm (weight) of the substance N and of less than 1000 ppb (weight), in particular of less than 500 ppb (weight), of the sum of all of the metals Ti, V, Fe, Ni.   
     
     
         51 . Method according to  claim 44 ,
 characterized by the step of   setting a pressure inside the process chamber ( 856 ) above 1 bar by introducing a defined amount of a mixture of the first source gas, which provides Si, and the second source gas, which provides C, into the process chamber, wherein the defined amount is an amount between
 0.32 g of the mixture per hour and per cm2 of a SiC growth surface and 10 g of the mixture per hour per cm2 of the SiC growth surface 
   or   setting a pressure inside the process chamber ( 856 ) above 1 bar by introducing a defined amount of a Si and C containing source gas or gases into the process chamber, wherein the defined amount is an amount between
 of the Si and C containing source gas or gases per hour and per cm2 of the SiC growth surface and 10 g of the Si and C containing source gas per hour and per cm2 of the SiC growth surface. 
   
     
     
         52 . Method according to  claim 51 ,
 characterized in that
 the process chamber ( 856 ) is surrounded by a base plate ( 862 ), a side wall section ( 864   a ) and a top wall section ( 864   b ), wherein more than 50% [mass] of the side wall section and more than 50% [mass] of the top wall section and more than 50% [mass] of the base plate is made of metal, in particular steel, wherein 
   a base plate and/or side wall section and/or top wall section sensor unit is provided to detect temperature of the base plate and/or side wall section and/or top wall section and to output a temperature signal or temperature data and/or a cooling fluid temperature sensor is provided to detect the temperature of the cooling fluid,   and   a fluid forwarding unit is provided for forwarding the cooling fluid through the fluid guide unit, wherein   the fluid forwarding unit is configured to be operated in dependency of the temperature signal or temperature data provided by the base plate and/or side wall section and/or top wall section sensor unit and/or cooling fluid temperature sensor.   
     
     
         53 . Method according to  claim 44 ,
 characterized in that   the SiC growth substrate has an average perimeter of at least 5 cm around a cross-sectional area orthogonal to the length direction of the SiC growth substrate or multiple SiC growth substrates have an average perimeter per SiC growth substrate of at least around a cross-sectional area orthogonal to the length direction of the respective SiC growth substrate.   
     
     
         54 . Method according to  claim 53 ,
 characterized in that   the SiC depositing on the SiC growth substrate ( 857 ) has impurities of less than 2 ppm (weight) of the substance N and of less than 100 ppb (weight) of each of the substances B, Al, P, Ti, V, Fe, Ni and wherein   the SiC depositing on the SiC growth substrate ( 857 ) has impurities of less than 10 ppb (weight) of the substance Ti.   
     
     
         55 . Method according to  claim 44 ,
 characterized in that   a gas outlet unit for outputting vent gas   a vent gas recycling unit,   wherein the vent gas recycling unit is connected to the gas outlet unit,   wherein the vent gas recycling unit comprises at least   a separator unit for separating the vent gas into a first fluid and into a second fluid,   wherein the first fluid is a liquid and wherein the second fluid is a gas,   wherein a first storage and/or conducting element for storing or conducting the first fluid is part of the separator unit or coupled with the separator unit   and   wherein a second storage and/or conducting element for storing or conducting the second fluid is part of the separator unit or coupled with the separator unit.   
     
     
         56 . Method according to  claim 55 ,
 characterized in that   the step of providing a source medium inside a process chamber, comprises feeding the first fluid from the vent gas recycling unit into the process chamber, wherein the first fluid comprises at least a mixture of chlorosilanes.   
     
     
         57 . Method according to  claim 56 ,
 characterized in that   the gases introduced into the CVD reactor ( 850 ) comprise less than 99.9999% (ppm wt) of one, multiple or all of the following substances B (Boron), Al (Aluminium), P (Phosphor), Ti (Titan), V (Vanadium), Fe (Eisen), Ni (Nickel).   
     
     
         58 . Method according to  claim 44 ,
 a crucible gas flow unit ( 170 ) for causing a gas flow inside the crucible volume is provided, wherein the crucible gas flow unit ( 170 ) comprises a crucible gas inlet tube ( 172 ) for conducting gas into the crucible volume ( 116 ) and a crucible gas outlet tube ( 174 ) for conducting gas out of the crucible volume ( 116 ).   
     
     
         59 . Method according to  claim 44 ,
 characterized in that   a growth guide ( 231 ) is arranged inside the crucible housing ( 110 ),   wherein the growth guide ( 231 ) forms a growth-guide-gas-path-section-boundary ( 232 ) for guiding the gas flow into the direction of the seed holder unit ( 122 ),   wherein the growth guide ( 231 ) and the seed holder unit ( 122 ) form a gas-flow passage ( 236 ),   and by the steps:   establishing gas flow through the crucible volume ( 116 ) by conducting at least a carrier gas into the crucible volume ( 116 ) through the crucible gas inlet tube ( 172 ) and by conducting at least the carrier gas out of the crucible volume ( 116 ) through the crucible gas outlet tube ( 174 )   establishing a defined gas flow velocity through the gas-flow passage by controlling gas flow through the crucible gas inlet tube ( 172 ) into the crucible volume ( 116 ) and/or establishing the defined gas flow velocity through the gas-flow passage by controlling gas flow through the crucible gas outlet tube ( 174 ) out of the crucible volume ( 116 ) wherein the defined gas flow velocity is between 1 cm/s and 10 cm/s and preferably between 2 cm/s and 6 cm/s.   
     
     
         60 . Method according to  claim 44 ,
 characterized in that   the receiving space ( 118 ) is located between the crucible gas inlet tube ( 172 ) and the seed holder unit ( 122 )   and by the step:   conducting gas flow around the receiving space ( 118 ) and/or through the receiving space ( 118 ).   
     
     
         61 . Method according to  claim 44 ,
 characterized in that   a filter unit ( 130 ) is arranged inside the crucible volume ( 116 ) between the seed holder unit ( 122 ) and the crucible gas outlet tube ( 174 ) for capturing at least Si 2 C sublimation vapor, SiC 2  sublimation vapor and Si sublimation vapor,   wherein the filter unit ( 130 ) forms a filter-unit-gas-flow-path ( 147 ) from a filter input surface ( 140 ) to a filter output surface ( 142 ), wherein the filter gas flow path is part of a gas flow path between the crucible gas inlet tube ( 172 ) and the crucible gas outlet tube ( 174 ), wherein the filter unit ( 130 ) preferably has a height S1 and wherein the filter-unit-gas-flow-path ( 147 ) through the filter unit ( 130 ) preferably has a length S2, wherein S2 is at least 2 times, in particular 10 times, longer compared to S1   and by the step:   guiding gas from the gas flow passage to the filter input surface ( 140 ) and from the filter input surface ( 140 ) through the filter unit ( 130 ) to a filter output surface ( 142 ) and from the filter output surface to the crucible gas outlet tube ( 174 ).   
     
     
         62 . Method according to  claim 44 ,
 characterized in that   a pressure unit ( 132 ) for setting up a crucible volume pressure (P 1 ) inside the crucible volume ( 116 ) is provided, wherein the pressure unit ( 132 ) is configured to cause crucible volume pressure (P 1 ) above 2666.45 Pa and preferably above 5000 Pa or in a range between 2666.45 Pa and 50000.00 Pa   and by the steps   Generating a crucible volume pressure (P 1 ) inside the crucible volume above 2666.45 Pa and preferably above 5000 Pa or in a range between 2666.45 Pa and 50000.00 Pa, wherein   the PVT reactor ( 100 ) comprises a crucible gas flow unit ( 170 ), wherein the crucible gas flow unit ( 170 ) comprises a crucible gas inlet tube ( 172 ) for conducting gas into the crucible volume ( 116 ), wherein the crucible gas inlet tube ( 172 ) is arranged in vertical direction below the receiving space ( 118 )   and the step   conducting gas via the crucible gas flow unit ( 170 ) into the crucible housing.   
     
     
         63 . SiC crystal ( 17 ) produced according to  claim 62 , characterized in that the SiC crystal ( 17 ) has impurities of less than 1000 ppb (weight), in particular of less than 500 ppb (weight), of the sum of all of the metals Ti, V, Fe, Ni, and wherein the SiC crystal ( 17 ) is a monocrystalline SiC crystal forming a monolithic block, wherein the monolithic block has a volume of more than 400 cm 3  and preferably of more than 5000 cm 3  and most preferably of more than 10000 cm 3 . 
     
     
         64 . System for the production of SiC which comprises
 a CVD reactor ( 850 ) for the production of SiC of a first type as PVT source material,   at least comprising   a process chamber ( 856 ), wherein the process chamber ( 856 ) is at least surrounded by a base plate ( 862 ), a side wall section ( 864   a ) and a top wall section ( 864   b ),   a gas inlet unit ( 866 ) for feeding one feed-medium or multiple feed-mediums into a reaction space of the process chamber ( 856 ) for generating a source medium,   wherein the gas inlet unit ( 866 ) is coupled with at least one feed-medium source ( 851 ), wherein a Si and C feed-medium source ( 851 ) provides at least Si and C, in particular SiCl3(CH3), and wherein a carrier gas feed-medium source ( 853 ) provides a carrier gas, in particular H2,
 or 
   wherein the gas inlet unit ( 866 ) is coupled with at least two feed-medium sources ( 851 ,  852 ),   wherein a Si feed medium source ( 851 ) provides at least Si, in particular the Si feed medium source provides a Si gas according to the general formula SiH 4-y X y  (X═[Cl, F, Br, J] and y=[0 . . . 4], and wherein a C feed medium source ( 852 ) provides at least C, in particular natural gas, Methane, Ethan, Propane, Butane and/or Acetylene, and wherein a carrier gas medium source ( 853 ) provides a carrier gas, in particular H2,   one or multiple SiC growth substrate ( 857 ), in particular more than 3 or 4 or 6 or 8 or 16 or 32 or 64 or up to 128 or up to 256, are arranged inside the process chamber ( 856 ) for depositing SiC,   wherein each SiC growth substrate ( 857 ) comprises a first power connection ( 859   a ) and a second power connection ( 859   b ),   wherein the first power connections ( 859   a ) are first metal electrodes ( 206   a ) and wherein the second power connections ( 859   b ) are second metal electrodes ( 206   b ),   wherein each SiC growth substrate ( 857 ) is coupled between at least one first metal electrode ( 206   a ) and at least one second metal electrode ( 206   b ) for heating the outer surface of the SiC growth substrates ( 857 ) or the surface of the deposited SiC to temperatures between 1300° C. and 1800° C., in particular by means of resistive heating and preferably by internal resistive heating, so that SiC of the first type is deposited onto the SiC growth substrate,   wherein the deposited SiC of the first type from the CVD reactor is used in a PVT reactor ( 100 ) for the production of SiC of a second type,   wherein the PVT reactor ( 100 ) comprises   a furnace unit ( 102 ),   wherein the furnace unit ( 102 ) comprises a furnace housing ( 108 ) with an outer surface ( 242 ) and an inner surface ( 240 ),   at least one crucible unit ( 106 ),   wherein the crucible unit ( 106 ) is arranged inside the furnace housing ( 108 ),   wherein the crucible unit ( 106 ) comprises a crucible housing ( 110 ),   wherein the crucible housing ( 110 ) has an outer surface ( 112 ) and an inner surface ( 114 ), wherein the inner surface ( 114 ) at least partially defines a crucible volume ( 116 ),   wherein a receiving space ( 118 ) for receiving a source material ( 120 ) in form of the SiC of the first type from the CVD reactor is arranged or formed inside the crucible volume ( 116 ),   wherein a seed holder unit ( 122 ) for holding a defined seed wafer ( 18 ) is arranged inside the crucible volume ( 116 ), wherein the seed wafer holder ( 122 ) holds a seed wafer ( 18 ),   wherein the furnace housing inner wall ( 240 ) and the crucible housing outer wall ( 112 ) define a furnace volume ( 104 ),   at least one heating unit ( 124 ) for heating the source material ( 120 ) in form of the SiC of the first type from the CVD reactor,   wherein the receiving space ( 118 ) for receiving the source material ( 120 ) in form of the SiC of the first type from the CVD reactor is at least in parts arranged above the heating unit ( 124 ) and below the seed holder unit ( 122 ),   adding the SiC of the first type from the CVD reactor as source material ( 120 ) into the receiving space ( 118 ),   sublimating the SiC of the first type inside the PVT reactor ( 100 ) and   depositing the sublimated SiC on the seed wafer ( 18 ) as SiC of the second type.   
     
     
         65 . System for the production of SiC which comprises
 a CVD reactor ( 850 ) for the production of SiC of a first type as PVT source material,   at least comprising   a process chamber ( 856 ), wherein the process chamber ( 856 ) is at least surrounded by a base plate ( 862 ), a side wall section ( 864   a ) and a top wall section ( 864   b ),   a gas inlet unit ( 866 ) for feeding one feed-medium or multiple feed-mediums into a reaction space of the process chamber ( 856 ) for generating a source medium,   wherein the gas inlet unit ( 866 ) is coupled with at least one feed-medium source ( 851 ), wherein a Si and C feed-medium source ( 851 ) provides at least Si and C, in particular SiCl3(CH3), and wherein a carrier gas feed-medium source ( 853 ) provides a carrier gas, in particular H2,
 or 
   wherein the gas inlet unit ( 866 ) is coupled with at least two feed-medium sources ( 851 ,  852 ),   wherein a Si feed medium source ( 851 ) provides at least Si, in particular the Si feed medium source provides a Si gas according to the general formula SiH 4-y X y  (X═[Cl, F, Br, J] and y=[0 . . . 4], and wherein a C feed medium source ( 852 ) provides at least C, in particular natural gas, Methane, Ethan, Propane, Butane and/or Acetylene, and wherein a carrier gas medium source ( 853 ) provides a carrier gas, in particular H2,   one or multiple SiC growth substrate ( 857 ), in particular more than 3 or 4 or 6 or 8 or 16 or 32 or 64 or up to 128 or up to 256, are arranged inside the process chamber ( 856 ) for depositing SiC,   wherein each SiC growth substrate ( 857 ) comprises a first power connection ( 859   a ) and a second power connection ( 859   b ),   wherein the first power connections ( 859   a ) are first metal electrodes ( 206   a ) and wherein the second power connections ( 859   b ) are second metal electrodes ( 206   b ),   wherein each SiC growth substrate ( 857 ) is coupled between at least one first metal electrode ( 206   a ) and at least one second metal electrode ( 206   b ) for heating the outer surface of the SiC growth substrates ( 857 ) or the surface of the deposited SiC to temperatures between 1300° C. and 1800° C., in particular by means of resistive heating and preferably by internal resistive heating, so that SiC of the first type is deposited onto the SiC growth substrate,   wherein the deposited SiC of the first type from the CVD reactor is used in a PVT reactor ( 100 ) for the production of SiC of a second type,   wherein the PVT reactor ( 100 ) comprises   a furnace unit ( 102 ),   wherein the furnace unit ( 102 ) comprises a furnace housing ( 108 ) with an outer surface ( 242 ) and an inner surface ( 240 ),   at least one crucible unit ( 106 ),   wherein the crucible unit ( 106 ) is arranged inside the furnace housing ( 108 ),   wherein the crucible unit ( 106 ) comprises a crucible housing ( 110 ),   wherein the crucible housing ( 110 ) has an outer surface ( 112 ) and an inner surface ( 114 ), wherein the inner surface ( 114 ) at least partially defines a crucible volume ( 116 ),   wherein a receiving space ( 118 ) for receiving a source material ( 120 ) in form of the SiC of the first type from the CVD reactor is arranged or formed inside the crucible volume ( 116 ),   wherein a seed holder unit ( 122 ) for holding a defined seed wafer ( 18 ) is arranged inside the crucible volume ( 116 ), wherein the seed wafer holder ( 122 ) holds a seed wafer ( 18 ),   wherein the furnace housing inner wall ( 240 ) and the crucible housing outer wall ( 112 ) define a furnace volume ( 104 ),   at least one heating unit ( 124 ) for heating the source material ( 120 ) in form of the SiC of the first type from the CVD reactor,   wherein the receiving space ( 118 ) for receiving the source material ( 120 ) in form of the SiC of the first type from the CVD reactor is at least in parts arranged above the heating unit ( 124 ) and below the seed holder unit ( 122 ),   adding the SiC of the first type from the CVD reactor as source material ( 120 ) into the receiving space ( 118 ),   sublimating the SiC of the first type inside the PVT reactor ( 100 ) and
 depositing the sublimated SiC on the seed wafer ( 18 ) as SiC of the second type.