Roughness Development in Metal Electrodeposition: I . Experimental Results

Copper electroforms of thicknesses of several hundred micrometers were produced by deposition on a rotating cylinder at rates of up to 5.0 A/cm2, corresponding to 110 μm/min. Digitalized surface profiles were analyzed by Fourier transform. Decline of roughness wavelength is observed with increasing current density at constant fraction of limiting current, in agreement with stability theory. Decline in roughness amplitude was also observed. This decline is due to an increase in the number density of nuclei. A comparison of the growth of features inside and outside the hydrodynamic boundary layer lends support to the growth mechanism proposed by Ibl in 1980.