| 摘要 |
PURPOSE:To form clean oxide films directly on the surface of silicon by a method wherein reducing gas is led into a reaction furnace arranged with silicon substrates and after heating the reaction furnace to remove the natural oxide films on the substrates, oxidizing gas is led in and the reaction furnace is reheated to form oxide films on the substrates. CONSTITUTION:When a quartz boat 14 loaded with silicon substrates 13 is inserted into the specified position in a quartz tube 12, a door 15 is closed and then nitrogen is continuously fed to the quartz tube 12 from the first gas lead-in pipe 16 for specified time, e.g., for ten minutes to be replaced with air that has been caught in. The nitrogen gas led into the quartz tube 12 is changed to hydrogen gas. Then, the quartz tube 12 is slowly heated, e.g., at the rate of 5 deg.C/min up to 800 deg.C-950 deg.C. After removing natural oxide films, the quartz tube 12 is cooled down to temperature hot exceeding 800 deg.C. After changing the hydrogen gas led from the first lead-in pipe 16 to nitrogen and substituting, e.g., for ten minutes, the second gas lead-in pipe 17 is opened to lead-in oxygen gas. Then, the quartz tube 12 is slowly reheated up to 850 deg.-950 deg.C to oxidize the silicon substrates 13.
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