Recovery of electrical resistance in copper films on polyethylene terephthalate subjected to a tensile strain

• Tensile tests on 200 nm Cu films on PET substrate are performed.
• Electrical resistance is recorded in-situ during loading and unloading.
• Significant recovery (decrease) of resistance is observed during and after unloading.
• Films strained to 5% demonstrate full resistance recovery.
• Viscoelastic relaxation of PET is responsible for recovery of Cu film resistance.

Substantial recovery (decrease) of electrical resistance during and after unloading is demonstrated for copper films on polyethylene terephthalate substrates subjected to a tensile strain with different peak values. Particularly, the films strained to 5% exhibit full resistance recovery after unloading despite clearly visible plastic deformation of the film. The recovery of electrical resistance in connection with the mechanical behavior of film/substrate couple is discussed with the help of in situ scanning electron microscopy and X-ray diffraction analysis.