Vacancy-impurity complexes and diffusion of Ga and Sn in intrinsic and p-doped germanium

The charge state of mobile vacancy-impurity complexes in germanium was studied via the effect of p-type (Ga) doping on Ga and Sn diffusions. Tin diffusion retards significantly as a function of doping concentration suggesting diffusion dominated by negatively charged vacancy-Sn complexes. Gallium diffusion is practically unaffected by doping, suggesting diffusion dominated by vacancy-Ga complexes having the same charge state as isolated, negatively charged Ga ions. The evident two orders of magnitude higher diffusivity of group V elements in germanium than of group III and IV elements can be well explicated by means of the present findings.