Pyrolytic boron nitride container for growing a crystal, and a method for growing a semiconductor crystal using the container

Providing a pyrolytic boron nitride container, whose cross-sectional shape maintains the shape of a perfect circle, even if its diameter is enlarged, and does not deform through repeated use. The pyrolytic boron nitride container of the present invention is a pyrolytic boron nitride container, which is used for a method for growing a semiconductor crystal, in which a melt of raw material, which is located in an elongated container, solidified by a container base in the direction of a container opening , The pyrolytic boron nitride container comprises a portion of constant diameter, the cross-sectional area is substantially constant, and a step portion which is provided at a predetermined position away from the opening, and on which an inner diameter or an outer diameter of the container changes. When a diameter of a perfect circle having the same area as an inner cross-sectional area of ​​the portion of constant diameter D, and a distance from the opening to an upper end of the step portion is x, the relations are D ≥ 54 mm and x ≥ 5 mm met. When a length from a lower end of the section is of constant diameter to the orifice 1, preferably the relation of 5 mm ≤ x ≤ L / 3 or 5 mm ≤ x ≤ D is satisfied.