P implantation into pre-amorphized germanium and subsequent annealing: solid phase epitaxial regrowth, P diffusion and activation

High fluence P implantation (30 keV, 3x1015 cm-2) into pre-amorphized Ge and subsequent rapid thermal or flash lamp annealing is investigated. In contrast to previous assumptions a significant P diffusion in amorphous Ge is not observed. However, during the fast solid phase epitaxial regrowth a rapid redistribution of P occurs. After completion of the regrowth and at temperatures above 500 0C, a concentration-dependent diffusion of P in crystalline Ge takes place. An appreciable influence of implantation defects on the diffusion coefficient of P cannot be found. For 60 s rapid thermal annealing at 600 0C and for 20 ms flash lamp annealing at 900 0C, the junction depth and the sheet resistance vary between 140 and 200 nm and between 50 and 100 Ohm , respectively, and the maximum electrical activation of P is about 3 – 7x1019 cm-3.