The Detailed Dependence of Implanted Phosphorus Profiles in (100) Single-Crystal Si on Key Implant Parameters

The continued decrease in semiconductor device feature size has required much smaller thermal processing budgets in order to achieve the required compact doping profiles. As a result, the impurity profiles have a larger dependence on the ion implant parameters, and more attention must be given to minimizing channeling, which results in deeper implanted profiles. Thus, there is a need for a detailed understanding of the dependence of the implanted profile on the key implant parameters. Since such an understanding does not exist for phosphorus implants in silicon, a detailed study has been performed by obtaining experimental phosphorus impurity profiles for a wide range of implant energies (15 - 180 keV), doses (lx1013- 8×1015 cm–2), tilt angles (0° - 10°), and rotation angles (0° - 360°). Channeling along the <100 axial channel dominates the variations. (110) planar channeling is the next most important channeling effect, appearing at higher (5°) tilt angles, where <100 axial channeling is suppressed. (100) planar channeling is not observed at the lower energies but does manifest itself for energies of 80keV and greater. Dose dependencies play a large role beginning around lxlO14 cm-2.