Processes and systems for carbon ion implantation include utilizing phosphorous trifluoride (PF3) as a co-gas with carbon oxide gas, and in some embodiments, in combination with the lanthanated tungsten alloy ion source components advantageously results in minimal oxidation of the cathode and cathode shield. Moreover, acceptable levels of carbon deposits on the arc chamber internal components have been observed as well as marked reductions in the halogen cycle, i.e., WFx formation.