RF SHEET-PLASMA SOURCE USING PERMANENT MAGNETS

摘要

A compact rf sheet-plasma source is investigated using a rectangular discharge chamber (200 x 100 x 20 mm) with a pair of permanent magnets placed on top and bottom of the chamber. A high-density [plasma density approx= (1.8 — 2.5) x 10~(12) cm~(-3) for electron temperature = 4 — 8 eV] and uniform (the width = 140 mm for a uniformity variation within 90%) plasma is produced using a 140-mm-long antenna for an Ar pressure of 20 mTorr and a rf power of 3 kW. Ion-saturation current-density J_(is) profile is controlled by varying the width of the magnets and/or the distance between the antenna and the magnets due to longitudinal line-cusps around the magnets. The measured J_(is) profiles are explained in terms of the motion of electrons under the cusped magnetic field.