Modifications to a standard Freeman ion source were made which increased11B+scanned wafer current by a minimum factor of 1.4, and11B2+,31P2+, and75As2+scanned wafer currents by a factor of 4.2. Order of magnitude increases in31P3+and75As3+scanned wafer currents were also measured in the extracted ion beam. Ion source feed materials were BF3gas and elemental phosphorus and arsenic. Filament lifetime using BF3gas has been observed to be in excess of 50 mA h. The apparent increased ionization efficiency was verified by a measured increase in electron density and temperature. In addition, at high extraction current densities (∼30 mA cm−2), the modifications resulted in a symmetric extracted ion beam and uniform filament erosion characteristics. Thus, it was concluded that the plasma uniformity has increased.