Patent ID: 7700156

Claim:
A method for forming a silicon oxide film having a film thickness of 1.6 nm or less, the method comprising: loading a target substrate that has a silicon layer on a surface into a process area within a reaction container, while setting the process area to have a loading temperature of 400° C. or less; generating water vapor in a water vapor generator disposed outside the reaction container, by causing hydrogen gas and oxygen gas to react with each other; increasing the temperature of the process area that accommodates the target substrate, from the loading temperature to a process temperature of 650° C. or more at an average temperature increasing rate of 50° C./minute to 100° C./minute; supplying the water vapor from the water vapor generator into the reaction container during said increasing the temperature of the process area, continuously from a time when the process area has a temperature of 400° C. or less to a time when the process area has the process temperature, while setting the water vapor to have a first concentration of 5 ppm to 1,000 ppm in an atmosphere of the process area, and setting the process area to have a first reduced pressure, thereby oxidizing the silicon layer to form an initial oxide film; and supplying an oxidation gas into the reaction container, after said increasing the temperature of the process area to the process temperature, thereby oxidizing the silicon layer to grow the initial oxide film, so as to form a silicon oxide film having a film thickness of 1.6 nm or less.