A Comparative Electrochemical Study of Copper Deposition onto Silicon from Dilute and Buffered Hydrofluoric Acids

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© 1998 ECS - The Electrochemical Society
, , Citation G. Li et al 1998 J. Electrochem. Soc. 145 241 DOI 10.1149/1.1838241

1945-7111/145/1/241

Abstract

An electrochemical direct current polarization method was used to investigate characteristics of copper deposition onto silicon from dilute and buffered hydrofluoric acid solutions. The corrosion current density and corrosion potential of silicon were not very sensitive to the concentration, up to 1000 parts per billion, in buffered hydrofluoric acid. However, the extent of copper deposition, as measured by total reflection X‐ray fluorescence, increased as the concentration in solution increased. In dilute hydrofluoric acid, addition had a significant and systematic effect on the corrosion potential and corrosion current density of silicon. However, in both types of solution, the cathodic current calculated from the measured copper deposition was found to be only a small fraction of the corrosion current (less than 1%). This indicates that the primary cathodic reaction is not copper ion reduction but hydrogen ion reduction. Illumination affected the electrochemical behavior of both p‐ and n‐type silicon in spiked dilute hydrofluoric acid, but only that of p‐type silicon in buffered hydrofluoric acid.

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10.1149/1.1838241