Complementary scanning tunneling microscopy and scanning electron microscopy studies of electroplated gold surfaces

The surface topography of gold electroplated as a function of current density has been studied by two topographical imaging techniques. Scanning tunneling microscopy (STM) was used to extend the magnification regime of scanning electron microscopy (SEM). STM micrographs of a 1×1‐μm scan area compare well with high resolution (50 000×) SEM micrographs. The surface of the gold was found to exhibit a distinct trend from an amorphous, porous appearance to a closely packed granular structure with decreasing current density. Surface roughness values extracted from STM data indicate a logarithmic dependence of roughness on the plating density.