The diffusion of implanted 7Be in Si1−xGex (x = 0.20, 0.65, 1.00) was studied under intrinsic conditions at 460 to 720C (tables 4 to 6) by using a modified radiotracer technique. Arrhenius-type behaviours, with activation enthalpies of 2.0eV for Ge and 2.5eV for the SiGe alloys was noted. It was unexpectedly found that the Be diffusivity was higher in Si0.80Ge0.20 than in Si0.35Ge0.65. This was explained in terms of the possible prevailing diffusion mechanisms. It was proposed that Be diffusion in Si1−xGex systems was dominated by a dissociative mechanism for Ge-rich materials, while the kick-out (or interstitialcy) mechanism predominated in Si-rich materials.

Diffusion of Beryllium in Ge and Si–Ge Alloys. O.Koskelo, P.Pusa, J.Räisänen, U.Köster, I.Riihimäki: Journal of Applied Physics, 2008, 103[7], 073513