Method and equipment for manufacturing aluminum nitride bulk single crystal

An apparatus for preparing a bulk monocrystalline aluminum nitride, comprising an autoclave (1) for producing a supercritical solvent, a convection-controller (2) arranged in the autoclave, and a furnace unit (4) equipped with a heater (5) and/or a cooler (6), in which the autoclave is set.

A process for preparing a bulk monocrystalline aluminum nitride, comprising the steps of dissolving an aluminum-containing feedstock in a supercritical solvent containing ammonia and ions of an alkali metal in an autoclave, to form a supercritical solution of aluminum nitride whose solubility has a negative temperature coefficient;

• and selectively growing a crystal of aluminum nitride only on the face of a crystallization seed arranged in the autoclave, from the supercritical solution introduced, by taking advantage of the negative temperature coefficient of the solubility of aluminum nitride.

A process for preparing a bulk monocrystalline aluminum nitride, comprising the steps of dissolving an aluminum-containing feedstock in a supercritical solvent containing ammonia and ions of an alkali metal in an autoclave, to form a supercritical solution of aluminum nitride whose solubility has a positive pressure coefficient;

• and selectively growing a crystal of aluminum nitride only on the face of a crystallization seed arranged in the autoclave, from the supercritical solution introduced, by taking advantage of the positive pressure coefficient of the solubility of aluminum nitride.

A process for preparing a bulk monocrystalline aluminum nitride, comprising the steps of dissolving an aluminum-containing feedstock in a supercritical solvent containing ammonia and ions of an alkali metal to form a supercritical solution of aluminum nitride whose solubility has a negative temperature coefficient;

• adjusting the solubility of the supercritical solution below a level of concentration where no spontaneous crystallization occurs, while maintaining oversaturation of the supercritical solution relative to a crystallization seed by raising the temperature to a predetermined temperature or reducing the pressure to a predetermined pressure, at least, in a zone in the autoclave where the crystallization seed is arranged;
• and selectively growing a crystal of aluminum nitride only on the face of the crystallization seed arranged in the autoclave, from said supercritical solution.