Cu Film Growth on a Si(111) Surface Studied by Scanning Tunneling Microscopy

We observed a change in growth mode of Cu, while dynamically observing Cu film growth on a Si(111)-7×7 surface during Cu deposition at room temperature by scanning tunneling microscopy (STM). Initially, Cu atoms were adsorbed mostly on the faulted halves of the 7×7 structure. Then, up to about 2 ML coverage, small Cu islands appeared. As the coverage increased from 2 to 3 ML, the growth mode changed into quasi-layer-by-layer growth. With further deposition, 3-D islands having hexagonal terraces grew.