Development of a simple 2.45 GHz microwave plasma with a repulsive double hexapole configuration

A simple and inexpensive 2.45 GHz microwave plasma source with a repulsive double hexapole configuration is described and characterized. In this work, the operation of the source is shown to be flexible in terms of electron density, electron temperature, and plasma uniformity even at low-pressures (approximately millitorr). It allows for easy control of the electron temperature (2-3.8 eV) and density (∼109-1010 cm-3) by removing either of the two hexapoles or by varying the separation distance between the two hexapoles. Characterization was done via information gathered from the usual Langmuir probe measurements for electron temperature and density. The source makes a resonant surface with its repulsive double hexapole magnetic configuration providing an additional longitudinal confinement near the walls midway between the two hexapoles. Magnetic field maps are presented for varying double hexapole distances. Power delivery for various settings is also presented.