Plasma reactor with overhead RF source power electrode with low loss, low arcing tendency and low contamination

摘要

A gas distribution ceiling electrode for use as a capacitive source power applicator and gas distribution showerhead in a plasma reactor includes a metal base and a process-compatible protective layer on the interior surface of he electrode having a dopant impurity concentration within a range corresponding to a minimal change in RF power absorption in the protective layer at an RF source power frequency with changes in coating temperature and or thickness. The metal base may have a set of first arcuately slotted gas passages and a set of pressure-dropping orifices coinciding axially with the top ends of the gas passages. The protective coating a set of arcuately slotted gas passages in registration gas passages of the metal base. The pressure drop in the orifices and the electric field drop in the slotted gas passages are both sufficient to maintain the pressure and electric field within the gas passages within a range that prevents arcing.