| 摘要 |
PURPOSE:To improve average film forming rate without saturation of a deposited film thickness by providing in the light incident window chamber a shutter which shields the reaction gas so that is cannot reach the light incident window chamber from the side of reaction vessel and also providing a vacuum exhaust port and a gas inlet port between the window and shutter. CONSTITUTION:Two or more light incident windows 11 are provided to a reaction vessel 13. Removal of cloudiness and reaction are carried out alternately so that removal of cloudiness and entrance of reactive excitation light are prevented to occur simultaneously at two windows. For the removal of cloudiness, the window chamber 12 is isolated from the reaction system with the shutter 21 and a gas which can remove deposition of window 11 by etching is supplied into the window chamber 12 in the side where the shutter is closed from the purging nozzle 23 at the surface of window 11 after vacuum exhaustion. In this case, in view of improving efficiency of etching reaction, the CO2 laser and Ar<+> laser are irradiated for heating through the window or the light which transmits through the window material and deposited substance and excites the etching gas is irradiated. |
