Plasma generation in electron cyclotron resonance

Apparatus for generating a plasma from a gas, comprising

• an evacuated chamber for receiving a volume of the gas,
• a microwave source connected by a waveguide to the chamber to deliver microwave power, via a window of the chamber, to initiate breakdown
• a magnetic field generator for establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power,
• the configuration of the waveguide and window being chosen with respect to a mode of propagation of the microwave power so that delivery of microwave power into the chamber and the breakdown both occur initially only in a region in the vicinity of the window.

Apparatus for generating a plasma from a gas, comprising

• an evacuated chamber for receiving a volume of gas,
• a microwave source to deliver microwave power, via a waveguide to a window of the chamber, the waveguide being of larger cross-section than the chamber,
• a magnetic field generator for establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, and
• a dielectric coupler, between the waveguide and the window, the coupler having a larger end for coupling to the waveguide, a smaller end for coupling to the window, and a dielectric material between the two ends, the ratio of the dimensions of the larger end, .PHI..sub.0 to the smaller end, .PHI..sub.e being .sqroot.e, where e is the dielectric constant of the dielectric material, every cross-sectional width of the larger end being larger than any cross-sectional width of the smaller end.

Apparatus for generating a plasma from a gas, comprising

• an evacuated chamber for receiving a volume of the gas,
• a microwave source connected to deliver microwave energy to the chamber,
• a magnetic field generator for establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power,
• the magnetic field generator comprising a pair of conductive current carrying coils coaxial with each other and with an axis of the chamber, the coils being spaced apart in a Helmholtz configuration,
• said evacuated chamber being of a dimension that is non-resonant with respect to propagation of the microwave power within the chamber in the absence of the plasma.

Apparatus for generating a plasma from a gas, comprising

• an evacuated chamber for receiving a volume of the gas,
• a microwave source connected by a waveguide to the chamber to deliver microwave energy, via a window of the chamber,
• a magnetic field generator for establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power,
• the waveguide including a microwave multiple stub tuner for tuning the propagation of electromagnetic waves from the microwave source to the plasma within the chamber to control the location and shape of the region in which the plasma is formed.

Apparatus for generating a plasma from a gas, comprising

• an evacuated chamber for receiving a volume of the gas,
• a microwave source connected to deliver microwave energy to the chamber,
• a magnetic field generator for establishing, within the chamber, a magnetic field to cause motion of the electrons to be resonant with a frequency of the microwave power, and
• a conduit which delivers the plasma from an end of the chamber and is sized to be non-resonant with respect to propagation of the microwave power.

Apparatus for generating a plasma from a gas, comprising

• introducing the gas into an evacuated chamber,
• delivering microwave power, via a window of the chamber,
• establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, and
• causing the evacuated chamber to have a dimension that is non-resonant with respect to propagation of the microwave power within the chamber in the absence of the plasma.

A method for generating a plasma from a gas, comprising

• introducing the gas into an evacuated chamber,
• delivering microwave power through a waveguide and via a window,
• establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power,
• the configuration of the waveguide and window being chosen with respect to a mode of propagation of the microwave power so that delivery of microwave power into the chamber and breakdown both occur initially only in a region in the vicinity of the window.

A method for generating a plasma from a gas, comprising

• introducing the gas into an evacuated chamber,
• delivering microwave power to the chamber,
• establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power, and
• providing, as the magnetic field generator, a pair of conductive current carrying rings coaxial with each other and with an axis of the chamber, the rings being spaced apart in a Helmholtz configuration.

A method for generating a plasma from a gas, comprising

• introducing the gas into an evacuated chamber,
• delivering microwave power through a waveguide and via a window,
• establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, and
• tuning a multiple stub microwave tuner in the waveguide to control the location and shape of the region in which the plasma is formed.

Apparatus for generating a plasma from a gas, comprising

• introducing the gas into an evacuated chamber,
• delivering microwave power to the chamber,
• establishing, within the chamber, a magnetic field to cause motion of electrons in the chamber to be resonant with a frequency of the microwave power, and
• providing a conduit to form a path for delivery of the plasma from an end of the chamber said conduit being sized to have arbitrary dimensions with respect to propagation of the microwave power.

Apparatus for generating a plasma from a gas for delivery to a work surface comprising

• an evacuated chamber for receiving a volume of the gas and delivering the plasma to the work surface,
• a microwave source connected to deliver microwave power to the chamber, and
• magnetic field generator for establishing within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power,
• the chamber having an insulative lining whereby the plasma may be delivered free of current, enabling the work surface to be held at ground potential or floating potential without disturbing the plasma characteristics.

Apparatus for generating a plasma from a gas, comprising

• introducing the gas into an evacuated chamber,
• delivering microwave power to the chamber,
• establishing, within the chamber, a magnetic field to cause the motion of electrons in the chamber to be resonant with a frequency of the microwave power, whereby a plasma is formed, and
• controlling the magnetic field to cause the formation of the plasma with high absorption of microwave power within selectably either a columnar or ring-shaped region centered on an axis of the chamber.