As one of a method of forming a high quality semiconductor film, there is an epitaxial growth technique of forming a single crystal film on a substrate such as a wafer by vapor phase growth. In a vapor phase growth apparatus using the epitaxial growth technique, a wafer is mounted on a support unit in a reaction chamber which is maintained in a normal pressure or a reduced pressure. Next, while heating the wafer, a process gas such as a source gas which is a raw material for film formation is supplied from, for example, a shower plate in an upper portion of the reaction chamber to a surface of the wafer. Thermal reaction of the source gas occurs on the surface of the wafer, so that a single crystal epitaxial film is formed on the surface of the wafer.
In recent years, as a material for a light emitting device or a power device, a GaN (gallium nitride)-based semiconductor device has attracted attention. As an epitaxial growth technique of forming a GaN-based semiconductor film, there is an organic metal vapor phase growth method (MOCVD method). In the organic metal vapor phase growth method, for example, organic metal such as trimethyl gallium (TMG), trimethyl indium (TMI), and trimethyl aluminum (TMA) or ammonia (NH3) or the like is used as a source gas.
JP-A H10-158843 and JP-A 2002-212735 disclose vapor phase growth apparatuses including a plurality of reaction chambers for improving productivity.