Interdiffusion was investigated in a Si/Si0.85Ge0.15/Si single quantum-well heterostructure which was subjected to thermal annealing in a nitriding ambient. It was found that nitridation of the Si surface altered the equilibrium vacancy populations throughout the structure. This permitted the monitoring of the point defect species which were important during interdiffusion. Following nitridation, Ge diffusion coefficients of 10-14cm2/s at 1100C, and 10-13cm2/s at 1200C were deduced (figure 20). The extent of diffusion in a nitriding ambient was much lower than that in an inert ambient. This reflected the existence of a minimal vacancy contribution to interdiffusion. This contrasted with the results of studies which had been performed in oxidizing ambients.

Diffusion of Single Quantum Well Si1-xGex/Si Layers under Vacancy Supersaturation. M.Griglione, T.J.Anderson, M.E.Law, K.S.Jones, A.Van den Bogaard, M.Puga-Lambers: Journal of Applied Physics, 2001, 89[5], 2904-6

Figure 20

Diffusivity of Ge in SiGe/Si Layers in Inert Ambient