| 摘要 |
PURPOSE:To uniformize a flow of a reactive gas, by forming a double-tube structure, in which a process tube comprises an inner tube and outer one, and uniting one part of the inner tube with the boat so that minute powder is prevented from being generated. CONSTITUTION:A process tube comprises an outer tube 3 for holding airtightness inside it and an inner one for CVD reaction. The inner tube is formed of a semiconductor wafer mounting part 2a and a fixed part 2b. Then, since most gases stay inside the inner tube, with no gas almost staying between the inner tube and the outer one 3, reaction is done mainly inside the inner tube, not occurring between the inner tube and outer one 3. Therefore, no film is piled at a position where the mounting part 2a of the inner tube comes in contact with the inner wall of the outer tube 3, preventing minute powder from being generated there. Hence, a flow of the reactive gas can be uniformized.
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