An investigation was made of the effect of a hydrostatic pressure upon interdiffusion in multi-layers that comprised alternating layers of amorphous Si (2.7nm) and Ge (3.1nm). The samples were annealed at 420C, under pressures of up to 2.8GPa, in a diamond anvil cell. The interdiffusion was monitored by measuring the decay, with annealing time, of the intensity of the first-order X-ray reflection that resulted from the effects of composition modulation. It was found that the decay curves for all pressures could be caused to coincide by scaling the annealing time (figure 2). This made it possible to separate the effects of pressure, upon interdiffusivity, from the effects of the composition and structural relaxation. The interdiffusivity increased with applied pressure, and the activation volume was equal to -5.0cm3/mol. This was -0.42 times the atomic volume of crystalline Si.

S.D.Theiss, F.Spaepen, M.J.Aziz: Applied Physics Letters, 1996, 68[9], 1226-8