Influence of dynamic annealing on the depth distribution of germanium implanted in (100) silicon at elevated temperatures

Abstract

Abstract(100) silicon wafers were implanted at elevated temperatures up to 600°C with l×lO15-5×1015 Ge+/cm2 using 120 keV. The wafers were tilted by 5–7° and rotated by 5–15°. The implanted germanium profile was monitored as a function of implant temperature using RBS-channelling. Considerable profile broadening was seen together with apparent mass germanium migration away from the surface in samples implanted at 300°C and above. Control implants into hot and cold samples simultaneously rule out excess loss of germanium from the heated wafers. Channelling data indicate that while room temperature implants lead to amorphisation, with hot implants good quality layers are obtained in which the germanium atoms occupy substitutional sites. Hot implants into a sample previously implanted with germanium at room temperature does not lead to any redistribution in the original germanium profile. This result indicates that the apparent enhanced indiffusion of germanium is not a radiation assisted phenomenon and could be explained by a considerable channelling of the implanted germaniumatoms along the <100> direction.