Abstract
Copper was electrodeposited potentiostatically in 0.05 M CuSO4 - 0.05 M H2SO4 aqueous solutions onto a TaN film sputtered on a silicon substrate. Two different electrolytic cell configurations were designed in order to discuss quantitatively the effect of gravitational level on the nucleation and growth of metal electrodeposition in detail: (a) a horizontal cathode surface facing downward over an anode (C/A) and (b) an anode over cathode (A/C). FE-SEM image demonstrates the progressive nucleation model on TaN substrate. A/C configuration introduces more number of nuclei than the case of C/A at a constant applied potential. Moreover, the comparison of nearest-neighbor distance distribution among precipitated particles with Poisson random distribution confirms the existence of ``exclusion zone'' The growth rate of the exclusion zone is surely influenced by the gravitarional level. Then, the potentiostatic electrodeposition was engaged in A/C configuration inside a centrifugal field. The nucleus number densty becames slightly insreasing the gravitational level. It is saturated above 100 G.
