Secondary ion mass spectroscopic measurements of B -doped superlattices were used to investigate the generation and diffusion of point defects. The effect of heavy Sb ion implantation and annealing (800 to 1000C) was analyzed. The enhanced diffusion of B from doping spikes in as grown and Sb-implanted layers was analyzed by solving the diffusion equation; using a computer model for various initial point defect distributions. In order to fit the secondary ion mass spectrometry profiles, the positively charged B interstitial diffusion coefficient was changed, from a default value of 0.68, to 0.45cm2/s. It was found that the molecular beam epitaxial growth process produced interstitials and vacancies with an almost constant average value of about 5 x 1016/cm3. The use of an Sb-implanted B modulation-doped superlattice permitted the depth profile of the defect concentration to be obtained.

Point Defect Concentrations, Distributions and Diffusivity in Thin Si MBE-Films: Experiments and Simulations Based on Profiling of Implanted Multiple Delta Doping Structures. D.Krüger, R.Kurps, H.P.Zeindl, U.Jagdhold: Solid State Phenomena, 1996, 47-48, 313-8