PURPOSE: To form a film having a uniform film thickness by forming a sample holder to a cylindrical shape, inclining a wafer supporting surface to a reactive gas supplying port and reducing the sectional area of the sample holder in a down stream direction so that the reactive gas flows as stable axisymmetrical flow.
CONSTITUTION: The sample holder 4 in a reaction tube 1 is formed to the cylindrical shape in which the inside wall of the cylinder is formed to an internally conical or pyramidal shape and the wafer supporting face 4b is inclined toward the reactive gas supplying port 1a to face said port. The sectional area of the upstream aperture 4a is, therefore, larger than the sectional area of the downstream aperture 4c and a flow passage 8 constitutes the passage reduced toward the downstream. The film forming treatment with this constitution is executed by supporting wafers 7 on the wafer supporting face 4b, heating the tube by a high-frequency induction coil 2, rotating the holder 4 by a revolving shaft 5 and admitting the reactive gas into the reaction tube from the upper aperture 4a. The reactive gas is thereby constricted to form a stable axisymmetrical flow so that the concn. of the reactive gas is uniformized in the circumferential direction.
KOBAYASHI JUNICHI
ONO YUICHI
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