Plasma source with multiple magnetic flux sources each having a ferromagnetic core

A method of exciting a plasma in a plasma chamber containing a gas and having a window transmissive of magnetic flux, comprising;

• introducing a gas into the plasma chamber;
• and
• applying radio-frequency energy to an antenna having a ferromagnetic core positioned adjacent to the plasma chamber window, the antenna and the ferromagnetic core being cooperatively configured to substantially follow each other, thus comprising coinciding shape and configuration to one another to induce in the plasma chamber plasma currents that flow in planes that are substantially parallel to the plasma chamber window.

A plasma source comprising:

• a plasma chamber adapted to receive a gas and having a window transmissive of magnetic flux;
• and
• two or more sources of magnetic flux, each magnetic flux source defining a single magnetic pole adjacent to a plasma chamber window, each magnetic flux source being laterally spaced apart from any other magnetic flux source so that during operation of the plasma source plasma generation in regions of the plasma chamber immediately adjacent to the magnetic flux sources is substantially greater than plasma generation in regions of the plasma chamber located between the two or more sources, wherein each magnetic flux source comprises a ferrite core formed from a plurality of individual ferromagnetic units loaded in a generally cylindrical container.