Production of Electron-Free Plasma by Using a Magnetic Filter in Radio Frequency Discharge

A source plasma is generated in a multipole-type device in oxygen by a radio frequency discharge at 13.56 MHz. A SmCo magnet array is mounted between source and target plasma sections as a magnetic filter. In the target section, almost electron-free plasma is obtained. The device can be operated in the pressure range of 10-3 to 10-1 Torr. The plasma densities in source and target plasmas are 109-1010 cm-3 and 108-109 cm-3, respectively.