PURPOSE: To suppress the creeping of raw material along a crucible wall and shorten the time from the filling of raw material to the growth of a crystal in a molecular beam epitaxial growth method by using a crucible made of pyrolytic boron nitride (pBN) and having mirror-polished inner surface near the opening part.

CONSTITUTION: The inner surface of a crucible part 1b near the opening of a crucible 1 made of pBN is mirror polished. A raw material element 2 (e.g. Al) is filled into the crucible and maintained at or above the melting point in high vacuum. Since the inner surface of the opening part 1b is mirror- polished, the creeping of Al can completely be prevented. An Al-containing semiconductor layer such as AlGaAs or InAlAs is grown on a substrate.