Ion implanter performance improvement for boron doping by using boron trifluoride (BF<inf>3</inf>) and hydrogen (H<inf>2</inf>) mixture gases

In recent years, a major challenge facing beamline implant tools is the low productivity of high dose p-type boron doping. A significant aspect of this challenge is the limited ion source life obtained when running boron trifluoride (BF ₃ ), the primary feed gas for boron doping. Use of BF ₃ often results in redistribution of tungsten within the arc chamber and source area due to the halogen cycle. Presented here are results of experiments using a mixture of boron trifluoride and hydrogen (BF ₃ /H ₂ ) as an alternative to BF ₃ . Tests were performed on the Entegris ^® source test stand as well as on high current ion implant tools in high volume manufacturing environments. The BF ₃ /H ₂ mixture demonstrated distinct productivity advantages, such as significant improvements in source life, with minimal change in beam current and other process parameters. Additionally the stability of the mixture and reliability of the package were evaluated to ensure quality and safety of this new material for semiconductor manufacturing.