Nanoparticles to Improve Mass Transport Inside Deep Recesses

Abstract

A high pH citrate electrolyte was used to electrodeposit Ni-Cu alloys and Ni-Cu-γ-Al2O3 nanocomposites into recessed microelectrodes and onto rotating cylinder electrodes. The patterned, recessed substrates were 500 μm deep with a 187 × 187 μm cross section, produced by X-ray radiation at the LSU synchrotron facility, Center for Advanced Microstructures and Devices. Copper deposition was diffusion controlled and used as a probe to assess changes in mass transport. Nickel deposition was kinetically controlled by keeping the nickel ions in comparable excess to the concentration of copper ions. In the micropost, the copper deposit concentration increased along the height indicative of a changing boundary layer thickness regardless if the particles were present or absent. The addition of alumina nanoparticles in the electrolyte led to an enhancement of copper concentration in the deposit, and hence an enhancement of its mass-transport rate. © 2003 The Electrochemical Society. All rights reserved.