Precise Diffusion Control in the Nanometer Range in n+/p and p+/n Ge Using Ion Implantation and Flash Lamp Annealing

We used Flash Lamp Annealing (FLA) to control dopant diffusion in the nm range in n+/p germanium junctions. The diffusion of phosphorus was slower when co-doping with fluorine at doses below 2×10
¹⁴
cm
^-2
compared to a sample without F doping. The diffusion lengths in samples with and without F were 6.7nm and 9.1nm, respectively. In addition, precise diffusion control below 7nm could be achieved without degrading the activation level in the sample with F doping. Owing to the slow rate of diffusion, this has quite a low impact on the deactivation of P. By co-doping F with boron, diffusion in the nm range can be achieved, demonstrating the potential for controlling B diffusion in Ge. Thus, ion implantation and FLA can be usefully applied in Ge CMOS fabrication processes.