摘要 |
Provided are a reaction tube, a substrate processing apparatus, and a method of manufacturing a semiconductor device capable of suppressing a non-uniform distribution of a gas in a top region to improve the flow of the gas and film uniformity within and between substrate surfaces. The reaction tube has a cylindrical shape, accommodates a plurality of substrates stacked therein, and includes a cylindrical portion and a ceiling portion covering an upper end portion of the cylindrical portion, the ceiling portion having a substantially flat top inner surface. A thickness of a sidewall of the ceiling portion is greater than that of a sidewall of the cylindrical portion. |