Abstract: A crucible has a first resistance heater is disposed in spaced relation above the top of the crucible and a second resistance heater with a first resistive section disposed in spaced relation beneath the bottom of the crucible and with a second resistive section disposed in spaced relation around the outside of the side of the crucible. The crucible is charged with a seed crystal at the top of an interior of the crucible and a source material in the interior of the crucible in spaced relation between the seed crystal and the bottom of the crucible. Electrical power of a sufficient extent is applied to the first and second resistance heaters to create in the interior of the crucible a temperature gradient of sufficient temperature to cause the source material to sublimate and condense on the seed crystal thereby forming a growing crystal.

Abstract: In a crystal growth apparatus and method, polycrystalline source material and a seed crystal are introduced into a growth ambient comprised of a growth crucible disposed inside of a furnace chamber. In the presence of a first sublimation growth pressure, a single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a first gas that includes a reactive component that reacts with and removes donor and/or acceptor background impurities from the growth ambient during said sublimation growth. Then, in the presence of a second sublimation growth pressure, the single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a second gas that includes dopant vapors, but which does not include the reactive component.

Abstract: In method of crystal growth, an interior of a crystal growth chamber (2) is heated to a first temperature in the presence of a first vacuum pressure whereupon at least one gas absorbed in a material (4) disposed inside the chamber is degassed therefrom. The interior of the chamber is then exposed to an inert gas at a second, higher temperature in the presence of a second vacuum pressure that is at a higher pressure than the first vacuum pressure. The inert gas pressure in the chamber is then reduced to a third vacuum pressure that is between the first and second vacuum pressures and the temperature inside the chamber is lowered to a third temperature that is between the first and second temperatures, whereupon source material (10) inside the chamber vaporizes and deposits on a seed crystal (12) inside the chamber.

Abstract: A physical vapor deposition method of growing a crystal includes providing a seed crystal and a source material in spaced relation inside of a growth crucible that is at least in-part gas permeable to an unwanted gas. The growth chamber is heated whereupon the source material sublimates and is transported via a temperature gradient in the growth chamber to the seed crystal where the sublimated source material precipitates. Concurrent with heating the growth chamber, a purging gas is caused to flow inside or outside of the growth crucible in a manner whereupon the unwanted gas flows from the inside to the outside of the growth crucible via the gas permeable part thereof.

Abstract: A sublimation grown SiC single crystal includes vanadium dopant incorporated into the SiC single crystal structure via introduction of a gaseous vanadium compound into a growth environment of the SiC single crystal during growth of the SiC single crystal.

Abstract: A method and system of forming large-diameter SiC single crystals suitable for fabricating high crystal quality SiC substrates of 100, 125, 150 and 200 mm in diameter are described. The SiC single crystals are grown by a seeded sublimation technique in the presence of a shallow radial temperature gradient. During SiC sublimation growth, a flux of SiC bearing vapors filtered from carbon particulates is substantially restricted to a central area of the surface of the seed crystal by a separation plate disposed between the seed crystal and a source of the SiC bearing vapors. The separation plate includes a first, substantially vapor-permeable part surrounded by a second, substantially non vapor-permeable part. The grown crystals have a flat or slightly convex growth interface. Large-diameter SiC wafers fabricated from the grown crystals exhibit low lattice curvature and low densities of crystal defects, such as stacking faults, inclusions, micropipes and dislocations.

Abstract: In a crystal growth apparatus and method, polycrystalline source material and a seed crystal are introduced into a growth ambient comprised of a growth crucible disposed inside of a furnace chamber. In the presence of a first sublimation growth pressure, a single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a first gas that includes a reactive component that reacts with and removes donor and/or acceptor background impurities from the growth ambient during said sublimation growth. Then, in the presence of a second sublimation growth pressure, the single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a second gas that includes dopant vapors, but which does not include the reactive component.

Abstract: In a method of forming polycrystalline SiC grain material, low-density, gas-permeable and vapor-permeable bulk carbon is positioned at a first location inside of a graphite crucible and a mixture of elemental silicon and elemental carbon is positioned at a second location inside of the graphite crucible. Thereafter, the mixture and the bulk carbon are heated to a first temperature below the melting point of the elemental Si to remove adsorbed gas, moisture and/or volatiles from the mixture and the bulk carbon. Next, the mixture and the bulk carbon are heated to a second temperature that causes the elemental Si and the elemental C to react forming as-synthesized SiC inside of the crucible. The as-synthesized SiC and the bulk carbon are then heated in a way to cause the as-synthesized SiC to sublime and produce vapors that migrate into, condense on and react with the bulk carbon forming polycrystalline SiC material.

Abstract: A method and system of forming large-diameter SiC single crystals suitable for fabricating high crystal quality SiC substrates of 100, 125, 150 and 200 mm in diameter are described. The SiC single crystals are grown by a seeded sublimation technique in the presence of a shallow radial temperature gradient. During SiC sublimation growth, a flux of SiC bearing vapors filtered from carbon particulates is substantially restricted to a central area of the surface of the seed crystal by a separation plate disposed between the seed crystal and a source of the SiC bearing vapors. The separation plate includes a first, substantially vapor-permeable part surrounded by a second, substantially non vapor-permeable part. The grown crystals have a flat or slightly convex growth interface. Large-diameter SiC wafers fabricated from the grown crystals exhibit low lattice curvature and low densities of crystal defects, such as stacking faults, inclusions, micropipes and dislocations.

Abstract: In a physical vapor transport growth technique for silicon carbide a silicon carbide powder and a silicon carbide seed crystal are introduced into a physical vapor transport growth system and halosilane gas is introduced separately into the system. The source powder, the halosilane gas, and the seed crystal are heated in a manner that encourages physical vapor transport growth of silicon carbide on the seed crystal, as well as chemical transformations in the gas phase leading to reactions between halogen and chemical elements present in the growth system.

Abstract: A method of fabricating an SiC single crystal includes (a) physical vapor transport (PVT) growing a SiC single crystal on a seed crystal in the presence of a temperature gradient, wherein an early-to-grow portion of the SiC single crystal is at a lower temperature than a later-to-grow portion of the SiC single crystal. Once grown, the SiC single crystal is annealed in the presence of a reverse temperature gradient, wherein the later-to-grow portion of the SiC single crystal is at a lower temperature than the early-to-grow portion of the SiC single crystal.

Abstract: In a crystal growth method, an enclosed growth crucible is provided inside of a growth chamber. The growth crucible has polycrystalline source material and a seed crystal disposed in spaced relation therein. The interior of the growth crucible is heated whereupon a temperature gradient forms between the source material and the seed crystal. The temperature gradient is sufficient to cause the source material to sublimate and be transported to the seed crystal where it precipitates on the seed crystal. A gas mixture is caused to flow into the growth crucible and between the polycrystalline source material and an interior surface of the growth crucible. The gas mixture reacts with an unwanted element in the body of the growth crucible to form a gaseous byproduct which then flows through the body of the growth crucible to the exterior of the growth crucible.

Abstract: In the growth of a SiC boule, a growth guide is provided inside of a growth crucible that is charged with SiC source material at a bottom of the crucible and a SiC seed crystal at a top of the crucible. The growth guide has an inner layer that defines at least part of an opening in the growth guide and an outer layer that supports the inner layer in the crucible. The opening faces the source material with the seed crystal positioned at an end of the opening opposite the source material. The inner layer is formed from a first material having a higher thermal conductivity than the second, different material forming the outer layer. The source material is sublimation grown on the seed crystal in the growth crucible via the opening in the growth guide to thereby form the SiC boule on the seed crystal.

Abstract: In SiC sublimation crystal growth, a crucible is charged with SiC source material and SiC seed crystal in spaced relation and a baffle is disposed in the growth crucible around the seed crystal. A first side of the baffle in the growth crucible defines a growth zone where a SiC single crystal grows on the SiC seed crystal. A second side of the baffle in the growth crucible defines a vapor-capture trap around the SiC seed crystal. The growth crucible is heated to a SiC growth temperature whereupon the SiC source material sublimates and forms a vapor which is transported to the growth zone where the SiC crystal grows by precipitation of the vapor on the SiC seed crystal. A fraction of this vapor enters the vapor-capture trap where it is removed from the growth zone during growth of the SiC crystal.

Abstract: In a physical vapor transport growth technique for silicon carbide a silicon carbide powder and a silicon carbide seed crystal are introduced into a physical vapor transport growth system and halosilane gas is introduced separately into the system. The source powder, the halosilane gas, and the seed crystal are heated in a manner that encourages physical vapor transport growth of silicon carbide on the seed crystal, as well as chemical transformations in the gas phase leading to reactions between halogen and chemical elements present in the growth system.

Abstract: A physical vapor transport system includes a growth chamber charged with source material and a seed crystal in spaced relation, and at least one capsule having at least one capillary extending between an interior thereof and an exterior thereof, wherein the interior of the capsule is charged with a dopant. Each capsule is installed in the growth chamber. Through a growth reaction carried out in the growth chamber following installation of each capsule therein, a crystal is formed on the seed crystal using the source material, wherein the formed crystal is doped with the dopant.

Abstract: A physical vapor transport growth system includes a growth chamber charged with SiC source material and a SiC seed crystal in spaced relation and an envelope that is at least partially gas-permeable disposed in the growth chamber. The envelope separates the growth chamber into a source compartment that includes the SiC source material and a crystallization compartment that includes the SiC seed crystal. The envelope is formed of a material that is reactive to vapor generated during sublimation growth of a SiC single crystal on the SiC seed crystal in the crystallization compartment to produce C-bearing vapor that acts as an additional source of C during the growth of the SiC single crystal on the SiC seed crystal.

Abstract: A sublimation-grown silicon carbide (SiC) single crystal boule includes a deep level dopant introduced into the SiC single crystal boule during sublimation-growth thereof such that in a continuous section of the boule that is not less than 50% of a continuous length of said boule, the deep level dopant concentration at the boule center varies by not more than 25% from the average concentration of the deep level dopant in the continuous section of the boule.

Abstract: A crystal is sublimation grown in a crucible by way of a temperature gradient in the presence of between 1 and 200 Torr of inert gas. The pressure of the inert gas is then increased to between 300 and 600 Torr, while the temperature gradient is maintained substantially constant. The temperature gradient is then reduced and the temperature in the crucible is increased sufficiently to anneal the crystal. Following cooling and removal from the crucible, the crystal is heated in the presence of oxygen in an enclosure to a temperature sufficient to remove unwanted material from the crystal. Following cooling and removal from the enclosure, the crystal surrounded by another instance of the source material is heated in a crucible in the presence 200 and 600 Torr of inert gas to a temperature sufficient to anneal the crystal.

Abstract: A method of fabricating an SiC single crystal includes (a) physical vapor transport (PVT) growing a SiC single crystal on a seed crystal in the presence of a temperature gradient, wherein an early-to-grow portion of the SiC single crystal is at a lower temperature than a later-to-grow portion of the SiC single crystal. Once grown, the SiC single crystal is annealed in the presence of a reverse temperature gradient, wherein the later-to-grow portion of the SiC single crystal is at a lower temperature than the early-to-grow portion of the SiC single crystal.