The diffusion of Ge on (111)Si at high temperatures was studied experimentally by means of second-harmonic microscopy, and was computed using molecular dynamics simulations and a Stillinger-Weber potential. The experimental results (table 46) could be described by:

D (cm2/s) = 6 x 102exp[-2.48(eV)/kT]

The simulations yielded essentially the same values; thus confirming the validity of the Stillinger-Weber potential for diffusional studies. A previously developed semi-empirical correlation also gave similar results. The simulations also furnished estimates of the corresponding parameters for intrinsic diffusion, and for the enthalpy and entropy of Ge adatom-vacancy pair formation on Si. The simulations also provided evidence of minor contributions, to intrinsic diffusion, which arose from atom exchange, as well as the effect of complex high-temperature islanding phenomena at ps time-scales.

Surface Diffusion of Ge on Si(111): Experiment and Simulation. C.E.Allen, R.Ditchfield, E.G.Seebauer: Physical Review B, 1997, 55[19], 13304-13

Table 46

Diffusivity of Ge on the (111) Surface of Si