It was shown, using Auger depth profiling, that the concentration profile at the initially sharp interface in amorphous Si/Ge multi-layers shifted, but remained sharp, during heat treatment (680K, 100h). Rapid Si diffusion resulted in the formation of an almost homogeneous Ge-Si amorphous solid solution. There was essentially no diffusion of Ge into the Si layer. This was considered to be direct evidence for a high concentration-dependence of the interdiffusion coefficient in the amorphous Si/Ge system, and was in accord with previous indirect results which were deduced from measurements of the decay of small-angle Bragg peaks, and from finite difference simulations.

Interdiffusion in Amorphous Si/Ge Multi-Layers by Auger Depth Profiling Technique. A.Csik, G.A.Langer, D.L.Beke, Z.Erdélyi, M.Menyhard, A.Sulyok: Journal of Applied Physics, 2001, 89[1], 804-6

Figure 7

Diffusivity of Ge in Si