A radio frequency (RF) driven plasma ion source has an external RF antenna, i.e. the RF antenna is positioned outside the plasma generating chamber rather than inside. The RF antenna is typically formed of a small diameter metal tube coated with an insulator. An external RF antenna assembly is used to...http://www.google.ca/patents/US6975072?utm_source=gb-gplus-sharePatent US6975072 - Ion source with external RF antenna
