<p>A high-current implanter for material modification has an ion source which can ionize typical process gases used in the semiconductor fabrication, such as BF₃, PH₃, SiF₄, CO₂, H₂, and N₂. The 300-mm tall beam is extracted from the ion source. The source is designed to allow tuning of its source parameter to change the ratio of single and molecular ions in the plasma. Recently, it was found that applying a negative potential to the bias electrode installed between the cathode and the plasma chamber improves the ionization efficiency of single ions compared to conventional methods. For example, this method was able to achieve the hydrogen same beam current with a reduction of up to 25% in arc current.</p> Graphical abstract <p></p>