As a method for forming a high-quality semiconductor film, there is an epitaxial growth technique which forms a film on a substrate, using vapor phase growth. In a vapor phase growth apparatus using the epitaxial growth technique, a substrate is placed on a support portion in the vapor phase growth apparatus which is maintained at normal pressure or reduced pressure. Then, a reaction gas, which is a raw material, is supplied to the substrate while the substrate is being heated. For example, the thermal reaction of the reaction gas occurs on the surface of the substrate and an epitaxial single-crystal film is formed on the surface of the substrate.
When a film is formed, the support portion is supported by a rotating body and the substrate is rotated by a bearing and a rotating mechanism which support a rotating shaft connected to the rotating body. When a film is formed, there is a concern that contaminants generated from the bearing or the rotating mechanism will be mixed with the film and will prevent a high-quality film from being formed.