| 摘要 |
PURPOSE:To reduce the powdery vapor-growth material formed and deposited in the title device by supplying the gas introduced from a gas inlet onto a diffusion plate from the gap between a gas guide plate and the side wall of a barrel through a laminar flow forming means. CONSTITUTION:A top board 2 having plural gas inlets at its center is fixed to the upper end face of the barrel 1, and the gas diffusion plate 7 is fixed to the lower end face of the barrel 1. The gases introduced from the plural gas inlet pipes 3 and 4 are individually formed into a thin laminar flow by the top board 2 and the gas guide plates 5 and 6, and induced to the periphery of the device from its center. The gases are then supplied onto the gas diffusion plate 7 from the periphery through the gaps between the inner wall surface of the device and the guide plates 5 and 6, and allowed to flow out in the form of a shower through the gas diffusion plate 7. As a result, the growth gas in the supply device flows only along the temp. gradient extending from a low temp. to a high temp., and the deposition of powdery SiO2, etc., due to the supersaturated reaction species is hardly caused in the device.
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