Influence of Implantation Damages and Intrinsic Dislocations on Phosphorus Diffusion in Ge

Influence of the implant-induced damages and the threading dislocations during germanium (Ge) epitaxy was investigated on the phosphorus diffusion in Ge. An adequate n-type junction was formed by 650°C rapid thermal annealing of the implanted bulk Ge. It is observed that for epitaxial Ge on Si substrate, there was an enhanced local phosphorus diffusion approaching the Ge/Si interface. A diffusion model considering the enhancement by defects is proposed to sufficiently explain the phosphorus diffusion profiles in Ge. The intrinsic dislocation-enhanced phosphorus diffusivity found at least three orders of magnitude larger than that in the absence of dislocations.