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.