Reliability of HfO2 metal-insulator-metal capacitors under AC stress

The electrical reliability of HfO2 based metal-insulator-metal capacitors is investigated under AC stress voltage. The capacitance-time (C-t) and conductance-time (G-t) responses are studied for different stress amplitudes and frequencies. Time-to-breakdown is observed to strongly depend on the electrode nature. Electrical degradation is discussed via a model based on oxygen vacancy/oxygen ions generation. Defect generation is controlled by the injecting nature of electrodes. Partial recovery, and so time-to-breakdown, are controlled by the ability of electrodes to store oxygen.