High current implanter dopant cross-contamination and its control

High current implanter boron cross-contamination in high dose arsenic implants is present in implanters used for multiple species applications. In this study, arsenic implant tests using total implant energy and extraction energy matrices from implanters immediately switched from boron processes were analyzed in order to understand the boron ion generation and transport mechanisms. The surface and deep level boron in the arsenic implanted wafers were analyzed by high mass resolution SIMS and ToF (Time-of-Flight) SIMS. Surface and energetic boron contamination were observed. The contaminate boron implant energy is directly related to the post-analyzer acceleration voltage. The surface contamination boron was primarily generated in the beamline by ion beam sputtering and then transported onto the wafers.