Crystal preparing device, crystal preparing method, and crystal

A crystal preparing method which produces a group III nitride crystal using a crystal preparing device, the crystal preparing device including a crucible holding a mixed molten metal containing alkali metal and group III metal, a reaction container having a container space which contacts the mixed molten metal and holding a molten alkali metal between the container space and an outside of the container, the molten alkali metal contacting the container space, and a piping disposed below the crucible and connected with the reaction container, the crystal preparing method comprising:

• a first step of placing the alkali metal and the group III metal into the crucible in an inert gas or nitrogen gas atmosphere;
• a second step of placing the alkali metal into the piping in the inert gas or nitrogen gas atmosphere;
• a third step of filling the container space of the reaction container with nitrogen gas;
• a fourth step of heating the crucible to a crystal growth temperature;
• a fifth step of heating the molten alkali metal at a specific temperature at which a vapor pressure of the alkali metal which evaporates from the molten alkali metal is substantially equal to a second vapor pressure of the alkali metal which evaporates from the mixed molten metal;
• and
• a sixth step of holding a temperature of the crucible to the crystal growth temperature, and holding a temperature of the molten alkali metal to the specific temperature for a predetermined time.