Surface Roughening in the Growth of Direct Current or Pulse Current Electrodeposited Nickel Thin Films

The surface roughening in the growth of direct current or pulse current electrodeposited nickel thin films at a low current density is investigated using atomic force microscopy (AFM). The growth exhibits scaling behaviors characterized by the roughness exponent α and growth exponent β. The analysis of the AFM images of the nickel thin films reveals that ( i ) for direct current electrodeposition: α = 0.96 and β = 0.78 , and ( ii ) for pulse current electrodeposition: α = 0.92 and β = 0.65 . Each value of α for the two techniques is almost in agreement with that predicted by a statistical model of linear diffusion dynamics. X-ray diffraction of the nickel thin films indicates the presence of preferred growth orientations that are related to the growth exponent β > 1 / 2 .