Mechanical stress field assisted charge de-trapping in carbon doped oxides

•Mechanical stress effects on leakage current are demonstrated.•Mechanical loading de-traps charges to increase leakage current.•Mechanical loading–unloading has hysteresis effect on leakage current.•At low electrical fields, mechanical stress may dictate dielectric reliability.

Leakage current and dielectric breakdown effects are conventionally studied under electrical fields alone, with little regard for mechanical stresses. In this letter, we demonstrate that mechanical stress can influence the reliability of dielectrics even at lower field strengths. We applied tensile stress (up to 8 MPa) to a 33% porous, 504 nm thick carbon doped oxide thin film and measured the leakage current at constant electrical fields (up to 2.5 MV/cm). The observed increase in leakage current at relatively low electric fields suggests that mechanical stress assists in trap/defect mediated conduction by reducing the energy barrier potential to de-trap charges in the dielectric.