Self-affine growth of copper electrodeposits

We have studied the static surface roughness of 50-μm-thick copper electrodeposits on length scales between 5 and 104 nm using scanning tunneling and atomic force microscopy. The surface roughness depends strongly on the concentration of organic additives in the plating solution. Both the surface width and power spectra scale as a power of the system size. Self-affine surfaces became more fractal-like with decreased additives. The scaling exponent of the self-affine surface (1/2) is slightly larger than the simulation results for local growth models.