PURPOSE: To shorten the time of rise and fall of growth pressure by letting carrier gas flow so as to do decompressed vapor growth after once breaking the supply of material gas and exhausting air from the inside of a reaction chamber, in laminating semiconductor crystalline layers different in properties by decompressed vapor growth.

CONSTITUTION: Period T1 is high pressure growth, period T2 is low pressure growth, and period T3 is vacuum exhaust, and period T4 is high pressure growth. To shift from the high pressure growth of period T1 to the low pressure growth of period T2, it shall be decompressed immediately as it is. To return to the high pressure growth from the low pressure growth, two sequences of periods T3 and T4 are required. Accordingly, when the low pressure growth of period T2 has finished, the material gas is stopped immediately so as to do vacuum exhaust, and then carrier gas is introduced and when it becomes stationary pressure, the material gas is introduced. This way, the time of rise and fall of the growth pressure can be shortened, and further the material gas never stays inside the reaction chamber 16.