Diffusion of single quantum well Si1-xGex/Si layers under vacancy supersaturation

The interdiffusion of a Si/Si0.85Ge0.15/Si single quantum well heterostruct ure subjected to thermal annealing in a nitriding ambient was investigated as a function of anneal temperature and time. Nitridation of the silicon su rface alters equilibrium vacancy point defect populations throughout the st ructure, which allows the determination of the point defect species importa nt in interdiffusion. Diffusion coefficients of Ge after nitridation of sim ilar to1 x 10(-14) cm(2)/s for 1100 degreesC and similar to1 x 10(-13) cm(2 )/s for 1200 degreesC were extracted. The extent of diffusion in a nitridin g ambient was much less than in an inert ambient, which indicates minimal v acancy contribution to interdiffusion. This is in contrast to results from previously published studies performed in an oxidizing ambient. (C) 2001 Am erican Institute of Physics.