Hj. Gossmann et al., TIME-DEPENDENCE OF DOPANT DIFFUSION IN DELTA-DOPED SI FILMS AND PROPERTIES OF SI POINT-DEFECTS, Applied physics letters, 64(3), 1994, pp. 312-314
The diffusion of Sb and B in thin Si films grown by low temperature mo
lecular beam epitaxy is investigated in the temperature range 750-900-
degrees-C for times of 0.25-60 h. The small spatial extent of the init
ial 5-function-like dopant profiles allows the detection of very small
diffusional displacements. The dopant atoms are used as tracers of Si
point defects (vacancies and self-interstitials). Diffusion of Sb is
found to be enhanced relative to equilibrium values, while that of B i
s retarded. We propose a model based on an initial supersaturation of
vacancies. Matching this model to the experimental data allows the ext
raction of the vacancy diffusivity, the activation energy of vacancy f
ormation, and the recombination lifetime of interstitials. The results
show that interstitial and vacancy populations cannot be considered i
ndependent at low temperature, as has been previously suggested.