초록 ▼

Atmospheric-pressure plasma jet. A .gamma.-mode, resonant-cavity plasma discharge that can be operated at atmospheric pressure and near room temperature using 13.56 MHz rf power is described. Unlike plasma torches, the discharge produces a gas-phase effluent no hotter than 250.degree. C. at an appli

Atmospheric-pressure plasma jet. A .gamma.-mode, resonant-cavity plasma discharge that can be operated at atmospheric pressure and near room temperature using 13.56 MHz rf power is described. Unlike plasma torches, the discharge produces a gas-phase effluent no hotter than 250.degree. C. at an applied power of about 300 W, and shows distinct non-thermal characteristics. In the simplest design, two concentric cylindrical electrodes are employed to generate a plasma in the annular region therebetween. A "jet" of long-lived metastable and reactive species that are capable of rapidly cleaning or etching metals and other materials is generated which extends up to 8 in. beyond the open end of the electrodes. Films and coatings may also be removed by these species. Arcing is prevented in the apparatus by using gas mixtures containing He, which limits ionization, by using high flow velocities, and by properly shaping the rf-powered electrode. Because of the atmospheric pressure operation, no ions survive for a sufficiently long distance beyond the active plasma discharge to bombard a workpiece, unlike low-pressure plasma sources and conventional plasma processing methods.

대표청구항 ▼

[ What is claimed is:] [1.] An apparatus for generating an atmospheric pressure plasma discharge which comprises in combination:a. an electrically conducting, grounded cylindrical chamber which is not tapered having a closed end, an open end, and a longitudinal axis;b. a cylindrical electrode locate

[ What is claimed is:] [1.] An apparatus for generating an atmospheric pressure plasma discharge which comprises in combination:a. an electrically conducting, grounded cylindrical chamber which is not tapered having a closed end, an open end, and a longitudinal axis;b. a cylindrical electrode located within said cylindrical chamber having a longitudinal axis and disposed such that the longitudinal axis thereof is collinear with the longitudinal axis of said cylindrical chamber, defining thereby an annular region;c. means for flowing gases through the annular region; andd. means for supplying rf energy to said cylindrical electrode such that a continuous plasma discharge occurs between said cylindrical electrode and said grounded chamber with no visible arcs being formed, the gaseous products of the plasma discharge exiting through the open end of said cylindrical chamber.