| 摘要 |
PROBLEM TO BE SOLVED: To obtain a plasma nitridation method by forming an oxide film on the surface of a semiconductor layer, injecting microwaves onto an atmospheric gas which consists substantially of nitrogen gas to produce excited nitrogen molecules, nitrogen molecule ions, nitrogen atoms, or nitrogen atomic ions, and nitriding the surface of the oxide film with these excited members. SOLUTION: A silicon semiconductor substrate 20 is fed into a double-pipe oxidizing furnace (processing chamber). By mixing hydrogen gas with oxygen gas at a high temperature, an element isolation region 21 of a LOCOS structure is formed, and a silicon oxide film is formed on the surface. Next, the resulting substrate 20 is fed to a plasma treatment system. After introducing nitrogen gas into the plasma processing, an atmospheric gas composed of 90% or more of nitrogen gas is irradiated with microwaves. Then, excited nitrogen molecules, nitrogen molecule ions, nitrogen atoms or nitrogen atomic ions collide against the surface of the oxide film in a plasma generating region, which nitrides the surface of the oxide film, and thus an insulating film 22 (silicon oxide nitride film which becomes a gate insulating film) is formed. As a result, an insulating film having superior properties can be obtained.
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