The surface morphology of Ge(001) films grown by molecular beam epitaxy on a Ge(001) substrate is measured using scanning tunneling microscopy. Growth mounds are observed for single crystal films deposited at temperatures of 60-230°C and film thicknesses of 5 nm to 1 μm. With increasing growth temperature, the average separation between mounds becomes increasingly well defined, increasing from less than 10 nm at 60°C to nearly 200 nm at 230°C. This regular arrangement of growth mounds is inconsistent with the self-affine growth morphology predicted by most kinetic roughening models.

• Received 11 July 1994

DOI:https://doi.org/10.1103/PhysRevLett.74.1127