Electrodeposition of copper on silicon from sulfate solution

In this paper, we report on the energetics and kinetics of copper depositio n on n-type Si(100), Si(111), and miscut Si(111) surfaces from 1 mM CuSO4 0.1 M H2SO4 solution. Electrochemical impedance spectroscopy showed that t he position of the band-edges at the surface is very similar for n-Si(100), n- Si(111), and miscut n- Si(111) surfaces. At more positive potentials, t he presence of electrically active surface states was observed. Cyclic volt ammetry and current transients showed that copper deposition occurs by prog ressive nucleation and diffusion-limited growth for the three surfaces, whi ch was confirmed by ex situ atomic force microscopy experiments. The rates for copper nucleation on Si(100) and Si(111) are essentially the same, whil e miscut Si(111) shows a slightly higher nucleation rate. These results ind icate that the energetics and kinetics of copper deposition from acidic sul fate solution on silicon are essentially independent of the silicon surface orientation. (C) 2001 The Electrochemical Society.