Metal-arc plasma ion implantation in a straight magnetic filter

Ion implantation is a well-known technique used in surface treatment of materials. During the 1980s, ion implantation using a sample immersed in an ionized gaseous medium (known as plasma immersion ion implantation) revealed to be an alternative to the conventional ion beam implantation. Development of this nonconventional surface processing using metallic ion species increased significantly when metal vacuum arcs began to be used as ion sources. In this paper, we present the experimental results obtained on Si wafers used as test targets, using metallic arc ion implantation. High-density plasmas (up to 10¹⁹ m^-3) made of aluminum vacuum arcs were used for the metallic implantation process. Arc currents of 200-700 A and 16 ms duration were pulsed every 30 s, and samples were biased from 2 kV to 10 kV with 50 μs pulses at 700 Hz, using a hard tube pulser. A straight magnetic filter was used to clean the plasma from macroparticle contaminants, with complete filtering being achieved in samples oriented so that their surfaces were parallel to the plasma stream. This is an interesting alternative to 90° curved magnetic duct filters usually used for this purpose. High-resolution X-ray diffraction analysis shows that aluminum was successfully implanted.