Ion Source of Pure Single Charged Boron Based on Planar Magnetron Discharge in Self‐Sputtering Mode

A planar magnetron sputtering device with thermally isolated sintered boron target has been designed and demonstrated. The magnetron is intended to use for generation of boron ion beams, as well as in plasma immersion implantation. For a boron target, high target temperature is required because boron has low electrical conductivity at room temperature, which increases with temperature. The target is well insulated thermally and can be heated by an initial low‐current, high‐voltage DC discharge mode. A discharge power of 16 W was adequate to reach the required surface temperature, after that a transition of the discharge to a high‐current, low‐voltage mode is observed. Applying high current pulses over the DC heating discharge results in a self‐sputtering operational mode of the magnetron discharge. Ion beam was extracted from the discharge plasma. Beam analysis was performed with a time‐of‐flight system. All the boron ions are single charged. The maximum boron ion fraction in the beam is greater than 99%,...