Phosphorus implantation (30 keV, 3x10(15) cm(-2)) into preamorphized Ge and subsequent rapid thermal or flash lamp annealing is investigated. During annealing a significant P diffusion in amorphous Ge is not observed. However, the fast solid phase epitaxial regrowth causes a rapid redistribution of P. After completion of the regrowth and at temperatures above 500 degrees C, a concentration-dependent diffusion of P in crystalline Ge takes place and leads to considerable loss of P toward the surface. An appreciable influence of implantation defects on the diffusion coefficient of P is not detected. For 60 s rapid thermal annealing at 600 degrees C and for 20 ms flash lamp annealing at 900 degrees C, the junction depth and the sheet resistance vary between 140 and 200 nm and between 50 and 100 Omega, respectively, and the maximum electrical activation of P is about 3-7x10(19) cm(-3). (c) 2008 American Vacuum Society.