Implant dopant activation comparison between silicon and germanium

We report room temperature p-type acceptor formation in Ge from B and C implant damage up to a level of 120Ω/□ or 1E19/cm³. For n-type dopant implants in Ge we found that an oxide surface capping layer was required above 625°C to prevent dopant surface loss. P followed by As then Sb gave the best dopant activation and at the same low temperature anneal B, P, As and Sb Rs values were always lower in Ge by 1.3x to 3x than in Si possibly directly related to the higher mobility ratio in Ge to Si and differences in Ge dopant surface loss and segregation into oxide.