PURPOSE: To prepare a grown film enhanced in hydrogen concn. uniformity by impressing a voltage between a shutter and a susceptor only when the shutter is inserted between a target electrode and the susceptor.
CONSTITUTION: A target electrode 1 capable of being heated and a substrate 4 opposed to the electrode are set in a chamber 6. The target electrode is connected to a high-frequency power source 3 through a matching box 2. A gas inlet line 7 and a gas outlet line 8 are provided to the chamber 6. A shutter 5 is arranged between the target electrode 1 and the substrate 4. A voltage is impressed between the shutter 5 and the susceptor 4 from a second power source only when the shutter 5 is inserted between the target electrode 1 and the susceptor (substrate 4). The inside of the device is easily cleaned in this way.