Active gas generation apparatus

An active gas generation apparatus comprising active gas generation electrodes and an alternating-current power source, said active gas generation electrodes including a first electrode and a second electrode provided below said first electrode, said alternating-current power source being configured to apply alternating-current voltage to said first and second electrodes so that said first electrode is at a high voltage,

• said first electrode including a first dielectric film and a first metal electrode on an upper surface of said first dielectric film, said second electrode including a second dielectric film and a second metal electrode on a lower surface of said second dielectric film, a space in which said first and second metal electrodes overlap each other in plan view defining a discharge space,
• a material gas supply path to provide a material gas to the discharge space from an external material gas supply, wherein
• an application of said alternating-current voltage by said alternating-current power source causing a discharge phenomenon in said discharge space, with the material gas therein, to generate an active gas, said active gas being ejected through a gas ejection port in said second electrode,
• each of said first and second dielectric films overlap said discharge space and a discharge exclusion space that is other than said discharge space, and
• said active gas generation apparatus further comprising:
• a first auxiliary member provided surrounding a side surface and an upper surface of said active gas generation electrodes;
• and
• a second auxiliary member having a main surface of an upper part on which said active gas generation electrodes and said first auxiliary member are arranged,
• an alternating-current voltage application space, separated from said discharge space, between said active gas generation electrodes and each of said first and second auxiliary members, said second auxiliary member including an auxiliary member gas discharge port through which active gas ejected from said gas ejection port passes, said first and second auxiliary members being integrally coupled, and
• said active gas generation apparatus further comprising:
• a housing of metal including a hollow space that houses all of said active gas generation electrodes and said second auxiliary member and at least part of said first auxiliary member, said housing including a housing gas discharge port through which the active gas passing through said auxiliary member gas discharge port is discharged to outside of said active gas generation apparatus, and a housing contact space between said housing and each of said first and second auxiliary members,
• wherein said first and second auxiliary members form part of the material gas supply path, through which externally supplied material gas is guided to said discharge space, independently from said alternating-current voltage application space so that gas flow in said discharge space and gas flow in said alternating-current voltage application space are separated from each other, and
• said active gas generation apparatus has features (1) to (5) below:
• (1) said second electrode supports said first electrode,
• (2) said first dielectric film includes a stepped part projecting downward in said discharge exclusion space, and a gap length of said discharge space is defined by a height of said stepped part,
• (3) a thickness of said discharge space is less than that of said discharge exclusion space,
• (4) said housing is fastened to said first auxiliary member only in an upper surface outside the hollow space to form said housing contact space in the hollow space without contacting a side surface of said first auxiliary member and a bottom surface of said second auxiliary member, and
• (5) all of said first and second auxiliary members are formed of metal material.