Origin of the stress-induced leakage currents in Al–Ta2O5∕SiO2–Si structures

The leakage currents in the Al–Ta2O5∕SiO2–Si structures increase as a result of the current stress. The case of the constant current stress was studied and it was found that the I–V characteristics of both unstressed and stressed samples can be described by the previously developed model involving Poole–Frenkel effect in the Ta2O5 and both hopping conductivity and tunneling in the SiO2. After extracting the parameters for both layers from the fitting of the theoretical curves to the experimental results, it was found that the main reason for the increased leakage is the partial destruction of the SiO2 layer.