Morphology and Electrical Properties of Copper Thin Films Electroplated on Ni/n+-Si(100) for Silicon Solar Contact

Cu thin films were electrodeposited on Ni/n+-Si(100) substrate from sulfuric solution with fixed pH at room temperature. The effect of deposition time of Cu coatings was studied by using the chronoamperometry method (CA), the atomic force microscopy (AFM), X-ray diffraction (XRD) and four point probe to investigate surface topography , structure and electrical properties of Cu films. From electrochemical measurements, the Cu film thickness ranging from 63 nm to 8.9 µm was calculated using Faraday's law. The AFM study showed a rugose surface of the Cu films and the variation of film morphology with deposition time were established. The XRD spectra revealed the formation of thin Cu films with a preferential orientation. Sheet resistance and resistivity showed strong dependence on the deposition time of Cu films. Cu films will be in the future metal contact for silicon solar cells.