A vertical type vapor-phase growth apparatus comprises a vapor-phase growth reactor constituted of an upper section defining an upper chamber having a lateral cross-section of about 200 cm.sup.2 and a lower section defining a lower chamber having a lateral cross-sectional area greater than, but smaller than four times the cross-sectional area of, the upper chamber, and a support for a semiconductor substrate disposed within the lower chamber. The support is in the form of a silicon plate on which a sample is directly placed.