Low-Energy Ion Implantation Using the Arsenic Dimer Ion: Process Characterization and Throughput Improvement

Low-energy arsenic implants used in the formation of ultrashallow junctions are characterized on a high current ion implanter. Significant advantages in beam current and process throughput are demonstrated by using the arsenic dimer ion (As + 2 ) for implant energies lower than 5 keV. Dimer implants require only half the dose and use twice the energy of equivalent As+ implants, resulting in significantly reduced implant times. Process results including Thermawave (TW), sheet resistance (R s ), secondary ion mass spectrometry (SIMS) profiles, electrical test and yield show equivalence between As + and As + 2 implants.