In a method of producing a SiC single crystal ingot of the present invention, in a lower part of a crucible, a high thermal conductivity raw material layer containing a high thermal conductivity raw material and a low thermal conductivity raw material layer containing a low thermal conductivity raw material in at least one of a position above or below the high thermal conductivity raw material layer are disposed to form a raw material part, and heating is performed so that the raw material part reaches the maximum temperature in the high thermal conductivity raw material layer and a SiC single crystal ingot is grown.

An apparatus for producing a Group-III nitride semiconductor crystal includes a raw material reaction chamber, a raw material reactor which is provided in the raw material reaction chamber and configured to generate a Group-III element-containing gas, a board-holding member configured to hold a board in the raw material reaction chamber, a raw material nozzle configured to spray the Group-III element-containing gas toward the board, a nitrogen source nozzle configured to spray a nitrogen element-containing gas toward the board, in which, in a side view seen in a direction perpendicular to a vertical direction, a spray direction of the nitrogen source nozzle intersects with a spray direction of the raw material nozzle before the board, and a mixing part in which the Group-III element-containing gas and the nitrogen element-containing gas are mixed together is formed around the intersection as a center, a heater, and a rotation mechanism.

A silicon carbide seed crystal and method of manufacturing the same, and method of manufacturing silicon carbide ingot are provided. The silicon carbide seed crystal has a silicon surface and a carbon surface opposite to the silicon surface. A difference D between a basal plane dislocation density BPD1 of the silicon surface BPD1 and a basal plane dislocation density BPD2 of the carbon surface satisfies the following formula (1):

D=(BPD1−BPD2)/BPD1≤25%  (1).

A manufacturing method of a silicon carbide wafer includes the following. A raw material containing carbon and silicon and a seed located above the raw material are provided in a reactor. A nitrogen content in the reactor is reduced, which includes the following. An argon gas is passed into the reactor, where a flow rate of passing the argon gas into the reactor is 1,000 sccm to 5,000 sccm, and a time of passing the argon gas into the reactor is 2 hours to 48 hours. The reactor and the raw material are heated to form a silicon carbide material on the seed. The reactor and the raw material are cooled to obtain a silicon carbide ingot. The silicon carbide ingot is cut to obtain a plurality of silicon carbide wafers. A semiconductor structure is also provided.

A silicon carbide wafer and a method of fabricating the same are provided. In the silicon carbide wafer, a ratio (V:N) of a vanadium concentration to a nitrogen concentration is in a range of 2:1 to 10:1, and a portion of the silicon carbide wafer having a resistivity greater than 10.sup.12 Ω.Math.cm accounts for more than 85% of an entire wafer area of the silicon carbide wafer.

A method for producing an ingot includes loading a raw material comprising a raw material powder having a D.sub.50 of 80 μm or more into a reactor (loading step), controlling the internal temperature of the reactor such that adjacent particles of the raw material powder are interconnected to form a necked raw material (necking step), and sublimating components of the raw material from the necked raw material to grow an ingot (ingot growth step).

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.

In various embodiments, single-crystal aluminum nitride boules and substrates are formed from the vapor phase with controlled levels of impurities such as carbon. Single-crystal aluminum nitride may be heat treated via quasi-isothermal annealing and controlled cooling to improve its ultraviolet absorption coefficient and/or Urbach energy.

A silicon carbide seed crystal and method of manufacturing the same, and method of manufacturing silicon carbide ingot are provided. The silicon carbide seed crystal has a silicon surface and a carbon surface opposite to the silicon surface. A difference D between a basal plane dislocation density BPD1 of the silicon surface BPD1 and a basal plane dislocation density BPD2 of the carbon surface satisfies the following formula (1):
D=(BPD1−BPD2)/BPD1≤25%  (1).

A device for producing single crystals of silicon carbide has a furnace and a chamber with a crucible and a seed crystal, the chamber being accommodated in the furnace, wherein a base material containing silicon carbide is arranged in the crucible, wherein the base material contains a mixture of silicon carbide powder and silicon carbide lumps.