Atomic-scale characterization of metal micro-electrodes grown on clean semiconductor surfaces

We have investigated the growth behavior of Ag micro-pads on the Si(1 1 1)7x7 and Si(1 1 1)-4x1-In surfaces, with particular attention to the morphology near the pad edges. Substrate surfaces in the vicinity of the pads have negligible extrinsic contamination or defects, maintaining their native atomic structures. In the case of the Si(1 1 1)7x7 surface, however, the surface always accompanies Ag clusters migrating from the pad regardless of the growth temperature. In contrast, the Si(1 1 1)-4x1-In surface is free of Ag clusters up to the pad edge when the growth is taken at low temperature. This sharp and well-defined boundary would be crucial for electrical connection to molecular assemblies formed on substrates