In Situ Stress Measurement of Ni Electrodeposition Using Lateral Shearing Interferometry

In-situ stress measurement has a significant benefit in revealing the deformation and failure mechanism during the deposition process. However, it is difficult to detect an ultrathin deposit and measure deposits of different scales simultaneously. Here, lateral shearing interferometry was used for in situ stress measurement of Ni deposits. we demonstrated that this method showed great stability and sensitivity during in situ process. Additionally, the accuracy of measurement was also been improved in terms of the measurement error (2.96%) and fluctuation (0.00035) of curvature radius. The system was capable of the measuring radius of curvature as large as 250 m. Theoretical calculation and experimental results coherently suggested that the thickness of measurable deposits can be diminished by decreasing the elastic modulus and thickness of the substrate. PMMA substrates can be used to measure the stress evolution of deposits with a thickness of more than 10 nm. Moreover, suitable substrate material and thickness for stress measurement of deposits with different scales can be selected by theoretical calculation before the experiment. This novel method provides valuable insights into the in situ stress towards the ultrathin deposit and paves the way to further understanding on the mechanism of deformation and failure of the deposition process in different states.