<i>In-Situ</i> Measurements of Stress during Electrodeposition of Copper Nanofilms: Effects of Deposition Rate and Grain Size

Stress was measured in situ during electrodeposition of copper nanofilms from 0.25 mol dm^-3 CuSO₄ in 1 mol dm^-3 H₂SO₄ at various growth rates. Grain size was measured using both in-situ AFM and ex-situ SEM imaging and showed that grain size increased with time for about the first 10 depositions and thereafter became approximately constant. Films deposited at low growth rates had compressive stress while films deposited at higher growth rates had tensile stress. The transition from compressive to tensile stress occurred at a growth rate of ~1 nm s^-1, in reasonable agreement with the literature. Our data supports Chason’s model for stress development during thin film deposition.