Si in-diffusion during the 3D islanding of Ge/Si(001) at high temperatures

The 3D islands of the Stranski-Krastanow system Ge/Si(001) that form either during the annealing of previously hat and nearly strain-relieved Ge films at 1020 K or directly at the Ge deposition at 1020 K are found to be compo sed of a mixture of Ge and Si, thus pointing to considerable interdiffusion at 1020 K. Direct measurement of the elastic energy unambiguously reveals that neither the 3D islanding nor the Si in-diffusion are driven by the red uction of misfit strain; this strain being the result of increasing configu rational entropy.