Systems, methods and apparatus for choked flow element extraction

A method of generating a plasma comprising:

• delivering a process gas into a ring plasma chamber having a plurality of gas inlet ports for receiving a process gas in the ring plasma chamber and a plurality of gas outlet ports that are vertically aligned with each of the plurality of gas inlet ports, the ring plasma chamber is a dielectric structure;
• applying a primary current to a primary winding around a circumference of the ring plasma chamber;
• generating magnetic field in the primary winding;
• concentrating the magnetic field with a plurality of ferrites, wherein the ring plasma chamber passes through each of the plurality of ferrites and wherein each turn of the primary winding passes through an inside portion of each of the plurality of ferrites;
• inducing a secondary current in the process gas in the ring plasma chamber;
• generating a plasma in the process gas in the ring plasma chamber with the secondary current;
• restricting the plasma in the ring plasma chamber with a plasma restriction in each of a plurality of plasma chamber outlets coupling the ring plasma chamber to a process chamber, wherein each of the plurality of gas inlet ports and each of the plurality of gas outlet ports are aligned with respective ones of the plurality of plasma chamber outlets;
• and
• biasing the plasma restriction of each of the plurality of plasma chamber outlets, the biasing acting to draw ions out of the plurality of plasma chamber outlets and into the process chamber.

A plasma system for processing a substrate, comprising:

• a process chamber having:
• a base;
• a plurality of sidewalls;
• a substrate support proximate to the base;
• and
• a chamber top interfaced with the sidewalls to enclose the process chamber;
• a plurality of ferrites disposed over the chamber top, such that the plurality of ferrites are distributed over regions of the substrate support, the regions extending at least between an exterior portion of the substrate support and a center portion of the substrate support;
• a ring plasma chamber having a plurality of gas inlet ports for receiving a process gas in the ring plasma chamber and a plurality of gas outlet ports that are vertically aligned with each of the plurality of gas inlet ports, and a primary winding wrapped around a circumference of the ring plasma chamber, the primary winding is disposed to pass through an inside portion of each of the plurality of ferrites, wherein each turn of the primary winding passes through the inside portion of each of the plurality of ferrites and around the circumference of the ring plasma chamber;
• and
• a plurality of plasma chamber outlets coupling the ring plasma chamber to the process chamber, and wherein each of the plurality of gas inlet ports and each of the plurality of gas outlet ports are aligned with respective ones of the plurality of plasma chamber outlets, and each one of the plurality plasma chamber outlets having a respective plasma restriction;
• wherein each of the plurality of ferrites has a substantial square shape and the ring plasma chamber has a rectangular cross-sectional shape, the substantial square shape of each of the plurality of ferrites fits around the rectangular cross-sectional shape of the ring plasma chamber;
• wherein the ring plasma chamber is made from a ceramic material;
• wherein the ring plasma chamber is disposed above the chamber top and separated from the chamber top by a bottom portion of each of the plurality of ferrites having the substantial square shape;
• a bias coupled to the plasma restriction of each of the plurality of plasma chamber outlets, the bias acting to extract ions out of the plurality of plasma chamber outlets and into the process chamber.