Kick-out diffusion of zinc in silicon at 1262 K

Penetration profiles of Zn in Si were recorded with the aid of the spreading-resistance technique after in-diffusion from the vapour phase at 1262 K. The conversion of resistance data into concentrations of substitutional Zn is based on an acceptor level at E V +0.24 eV detected by Hall effect measurements on the authors' Zn-diffused samples. The diffusion behaviour is found to be affected by surface conditions. In dislocation-free Si crystals with damaged surfaces the profile shape as well as the incorporation rate of Zn reveal a self-interstitial-limited diffusivity which depends on C -2 . Together with the much larger diffusion constant in highly dislocated samples this provides strong evidence that Zn in Si migrates by the kick-out mechanism.