Diffusion of ion-implanted boron in germanium

The diffusion of boron (B) in germanium (Ge) is studied. B was introduced in Ge wafers by ion implantation, and concentration profiles after furnace annealing 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 850 degreesC by fitting experimentally obtained profiles. This value of diffusion coefficient is at least two orders of magnitude lower than the minimum value reported in the literature for B diffusion in Ge. The results are significant as they question the general agreement about vacancy diffusion as the mechanism responsible for diffusion of B in Ge. (C) 2001 American Institute of Physics.