Trap parameters and conduction mechanism in HfO2-Ta2O5 mixed stacks in response to microwave irradiation

The effect of microwave treatment at room temperature on the leakage current and mechanisms of conductivity in mixed HfO"2-Ta"2O"5 (10nm) stacks has been studied by temperature dependent (20-100^oC) current-voltage characteristics. It was established that the short term irradiation (~6s) affects the electrically active centers in the mixed oxide, provokes modification of the dominant conduction mechanism at about and above 1MV/cm and improves the temperature stability of capacitors manifesting as low level of current at high temperatures (current decrease up to two orders of magnitude at 100^oC after the treatment is detected). The traps involved in the conduction processes in pre- and post-irradiation capacitors are identified. The longer exposure (10-15s) is effective in a significant reduction of leakage current (up to 3-4 orders of magnitude in wide range of applied voltages). The potential of microwave treatment at room temperature as technological step for improving the temperature stability of leakage current in high-k stacked capacitors is discussed.