Low particulate reliability enhanced remote microwave plasma discharge device

Claim 1

In a system for supplying a plasma to a vacuum process reactor, the combination comprising: a reactant gas conduit, said conduit having an inlet section, a center section and an outlet section, said inlet and outlet sections being comprised of water cooled double walls and being made of a quartz material, the center section of said conduit being made of a sapphire material which does not react to the reactive species of an activated reactant gas to be flowed through said sections; a reactant gas supplied to said inlet section and flowing through said conduit to said reactor; a source of pulsed microwave energy having a given wavelength; a coupling device coupling said source of microwave energy to the reactant gas in said center section of said conduit, said coupling device comprising an impedance matching device connected to said source and a tunable non-conducting circular waveguide extending from said impedance matching device to an axially adjustable short, said conduit extending transversely through said waveguide, the length of said waveguide from said impedance matching device to said short being 1/2 wavelength, a center axis of said conduit being located 1/4 wavelength from said impedance matching device, and 1/4 wavelength from said adjustable short, said waveguide having a water cooled double wall cylindrical jacket, said jacket having cylindrical extensions projecting transversely therefrom, sand the center section of said conduit being surrounded by said jacket; and means for axially adjusting the position of said short.