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ABSTRACT:
Ka-Ngo
Leung and colleagues have developed a robust, efficient antenna
system that is placed outside the plasma chamber of an ion
source. Internal antennas are normally covered with a dielectric
material such as porcelain or quartz in order to reduce sputtering
and to enhance plasma source efficiency, but these exhibit
limited lifetime due to mechanical failures.
Besides
having a long lifetime, the external antenna system has several
advantages over internal antennas. First, repairs can be made
without opening the plasma chamber. Second, a large number
of turns can be made in the antenna coil, allowing the discharge
to be easily operated in the inductive instead of the capacitive
mode. This feature results in less sputtering on the metallic
chamber wall. Third, plasma loss to the antenna structure
is greatly reduced when the antenna is located outside the
chamber, enabling the design of compact ion sources.
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