Active gas generating apparatus

1. An active gas generating apparatus that generates an active gas obtained by activating a raw material gas supplied to a discharge space, the active gas generating apparatus comprising:

a first electrode component; and

a second electrode component provided below said first electrode component, wherein:

said first electrode component has a first electrode dielectric film and a first metal electrode formed on an upper surface of said first electrode dielectric film, said second electrode component having a second electrode dielectric film and a second metal electrode formed on a lower surface of said second electrode dielectric film, an AC voltage being applied to said first metal electrode, said second metal electrode being set to a ground potential, and a dielectric space in which said first and second electrode dielectric films face each other including, as said discharge space, an area where said first and second metal electrodes overlap each other in plan view;

said first electrode dielectric film has, at its center, a gas supply port for supplying said raw material gas to said discharge space, said gas supply port being provided not to overlap said first metal electrode in plan view;

said second electrode dielectric film has at least one gas ejection hole for ejecting said active gas downward;

said first electrode component further has an auxiliary conductive film formed, independently of said first metal electrode, on said upper surface of said first electrode dielectric film;

said discharge space is formed to surround said gas supply port without overlapping said gas supply port in plan view;

said at least one gas ejection hole is arranged such that a distance from said gas supply port is larger than a distance from said discharge space without overlapping said gas supply port and said discharge space in plan view, and in said dielectric space, a path from said discharge space to said at least one gas ejection hole is defined as an active gas flow path;

said auxiliary conductive film surrounds said first metal electrode without overlapping said first metal electrode in plan view, and overlaps part of said active gas flow path in plan view;

said active gas generating apparatus further comprises

an electrode auxiliary member that is provided to contact part of an upper surface of said auxiliary conductive film and that has conductivity; and

said auxiliary conductive film is set to a ground potential via said electrode auxiliary member.

2. The active gas generating apparatus according to claim 1 , wherein:

said second electrode dielectric film has a protruding area whose upper portion protrudes along an outer periphery in plan view; and

said first and second electrode dielectric films are laminated such that a lower surface of said first electrode dielectric film contacts an upper surface of said protruding area of said second electrode dielectric film, and a closed space shielded from an outside is formed, as said dielectric space, between said lower surface of said first electrode dielectric film and an upper surface of said second electrode dielectric film.

3. The active gas generating apparatus according to claim 1 , further comprising

a base flange that is provided below said second electrode component, that supports said second electrode component by contacting said second metal electrode, and that has conductivity, wherein:

said base flange has at least one base flange gas ejection hole for ejecting downward an active gas ejected from said at least one gas ejection hole;

said electrode auxiliary member is fixed to said base flange in a state of being electrically connected to said base flange; and

a ground potential is applied to said base flange.

4. The active gas generating apparatus according to claim 3 , wherein

said at least one base flange gas ejection hole provided in said base flange includes a plurality of base flange gas ejection holes, and said plurality of said base flange gas ejection holes are radially separated and arranged in plan view.