The authors investigate F as a non-dopant co-implant to suppress P and As diffusion in Ge. F was placed either overlaying the dopant profile, or deeper to counteract the influence of end-of-range defects, which is a common ultra-shallow junction optimization approach in Si substrates. It was determined that F outgasses extremely quickly from Ge, as a 1x10(15) cm(-2) implanted dose escaped completely during a rapid thermal anneal as short as 1 sec, at 600 degrees C. This behavior is attributed to rapid diffusion, instability of F-defect clusters, and an aversion of F to reside substitutionally in the Ge lattice. The F diffusivity at 600 degrees C is in the order of some metal impurity diffusivities at that temperature.