The damage and annealing behavior of single-crystal Si(100) samples implanted with 480 keV P+ ions with a dose of 1×1016cm-2 have been studied.Samples were analysed with RBS/channeling and cross-sectional TEM techniques.The result indicates that there is a low density defects band at the depth of 240 nm after annealing at 600℃ for 30min.This phenomenon is related to P+ dose and annealing temperature.