The growth of Ge on Bi-terminated Si(111) root 3 X root 3 has been investigated by scanning tunneling microscopy (STM) and X-ray standing waves (XSW). In the Ge thickness range from 1 to 15 bilayers (BL), the morphology of the Ge film surface undergoes drastic changes. At low coverages, a smooth layer-by-layer growth mode of pseudomorphically strained Ge is found. Further Ge deposition leads to the formation of clusters of triangular partially relaxed Ge islands with a side length of approximately 200 Angstrom and an average island height of approximately 20 Angstrom. The islands act as catalyst for further island formation and for the relaxation of the complete Ge film by dislocation formation. Finally with increasing Ge film thickness, the surface morphology changes again. Ge films exceeding a thickness of similar to 8 BL are almost completely relaxed and smooth. Hence, Bi can be concluded to successfully art as a surfactant for Ge epitaxy on Si(111).