PURPOSE: To supply a material gas smoothly, by making the form of a semiconductor reaction container in a semiconductor vapor growth device have a Y form structure and one of two branches of the Y form act as an exclusive port for taking in and out the material gas in both a wafer and susceptor.

CONSTITUTION: A semiconductor vapor growth device makes the form of a semiconductor reaction container have a Y form. Material gases such as AsH3, H2Se and No gases are introduced from a gas supply port 21 and the material gases are introduced slantwise from the upper side to the surface of a wafer 20 on a susceptor 23 which is heated by a high frequency heating coil 25. As the introducing direction 26 of the material gases becomes at an angle with respect to an ascending current of air 27 which takes place on the surface of the wafer 20, the material gas is supplied smoothly in comparison with the case of conventional reaction tubes. Further, reaction products and waste gases which are produced after reaction are discharged smoothly by going into the ascending current of air 27 and the stream 28 of a gas flow moving toward a discharge port.