Diffusion of ion-implanted boron in germanium

The diffusion of boron (B) in germanium (Ge) is studied. B was introduced i n Ge wafers by ion implantation, and concentration profiles after furnace a nnealing were obtained using secondary ion mass spectroscopy. The diffusion coefficient and solid solubility of B in Ge has been calculated to be 1.5( +/-0.3)x 10(-16) cm(2)/s and 5.5(+/-1.0) x 10(18)/cm(3), respectively, at 8 50 degreesC by fitting experimentally obtained profiles. This value of diff usion coefficient is at least two orders of magnitude lower than the minimu m value reported in the literature for B diffusion in Ge. The results are s ignificant as they question the general agreement about vacancy diffusion a s the mechanism responsible for diffusion of B in Ge. (C) 2001 American Ins titute of Physics.