Induction vs. conventional heating: Impact on the morphology and crystallinity of copper electrodeposits on nickel

Due to its low cost and versatility, copper (and its oxides) is used in many applications such as microelectronics, catalysis, sensing, etc. In this work, we report on the study of copper electrodeposition on nickel substrates and the compared effect of a conventional heating of the electrolyte and an induction heating of the nickel substrate on copper deposits morphology at two different steps: at very early stages (copper particles) and after longer electrodeposition times (copper coatings). Regarding the copper particles electrodeposition, we show that in temperature-equivalent conditions conventional heating leads to a low coverage of the nickel electrode with weakly adherent copper microparticles (with a very large size distribution) whose growth could be subjected to a mass-diffusion limitation while induction heating leads to a high coverage of the surface with well adherent copper nanoparticles (with a sharp unimodal size repartition) avoiding any diffusion limitation. GIXRD analysis of these coatings revealed the systematic presence of both crystalline copper and crystalline copper oxide when induction heating is applied during the electrodeposition. This behavior is also observed in the frame of the formation of complete copper coatings i.e. induction heating allows to avoid mass-diffusion limitations in temperature-equivalent conditions leading to highly structurated coatings.